O'Hara and Comcare (Compensation) - [2025] ARTA 638

O'Hara and Comcare (Compensation) [2025] ARTA 638 (23 May 2025)
Applicant/s:  Damon O'Hara
Respondent:  Comcare
Tribunal Number:                2023/9810

Tribunal:R Cameron General Member
Place:Melbourne
Date:23 May 2025

Decision:The Tribunal affirms the decision under review.

.....................[SGND].......................................
R Cameron General Member
Catchwords
COMPENSATION – deny liability to the Applicant under Safety Rehabilitation Act 1988 – claimed condition of irritable bowel syndrome (‘IBS’) – determination of ailment or aggravation of ailment – if this constitutes a disease – determination of whether it was contributed to by applicant’s employment in the Commonwealth – waterborne disease theory – post-traumatic stress disorder aggravating applicant’s IBS theory – decision affirmed.
Legislation
Safety, Rehabilitation and Compensation Act 1988 ss 14, 62
Cases
Arnotts Ltd & Ors v Trade Practices Commission (1990) 97 ALR 555
Makita (Australia) Pty Ltd v Sprowles (2001) 52 NSWLR
Robinson and Military Rehabilitation and Compensation Commission [2006] AATA 506
Secondary Materials
American Journal of Gastroenterology, Vol 1, Issue 1, July 2012, Collins, Chang and Mearin, “Postinfectious Chronic Gut Dysfunction: From Bench to Bedside".
Deiteren, de Wit, van der Linder, De Man, Pelckmans, De Winter, “Irritable Bowel Syndrome and Visceral Hypersensitivity: Risk Factors and Patho-physiological Mechanisms." Acta Gastro-Enterologica Belgica, Vol LXXIX.
Dudzinska, Grabrucker, Kwiatowski, Sitarz and Sienkiewicz, “The importance of Visceral Hypersensitivity in Irritable Bowel Syndrome-Plant Metabolites in IBS Treatment." Pharmaceuticals (Basel); 16 (10).
Statement of Reasons
INTRODUCTION

The applicant seeks review in this Tribunal of a decision made by a Director, Claims Management of the respondent 12 December 2023 which affirmed a previous decision to deny liability to the applicant under s 14 of the Safety, Rehabilitation and Compensation Act 1988 (‘the SRC Act’) for a claimed condition of irritable bowel syndrome (‘IBS’) (‘the reviewable decision’).[1]
[1] JTB 15.
THE EVIDENCE BEFORE THE TRIBUNAL
There was both oral and documentary evidence before the Tribunal. The following witnesses gave oral evidence:
(a)The applicant;
(b)Dr Sethi, a consultant gastroenterologist and hepatologist.
Documentary evidence was adduced in a Joint Tribunal Book (‘JTB’) which comprises 1030 pages of documentation concerning the application.
After the evidence had concluded the applicant sought to tender documents that were attached to the letters of instruction to Dr Sethi sent by the respondent’s lawyers.[2] They were not included in the JTB. Unfortunately, whilst the hearing continued these documents were not able to be produced to the Tribunal. They have since been lodged by the applicant and examined by the Tribunal. Such documents will be received in evidence.
[2] The letter of instruction to Dr Sethi dated 19 May 2023 and attached documentation comprised a further 346 pages.
THE ISSUES FOR DETERMINATION BY THE TRIBUNAL
The following issues it is considered arise for determination by the Tribunal in these applications:
(a)Does the applicant suffer from an ‘ailment’ or an ‘aggravation’ of an ailment? If so,
(b)Is the ailment or aggravation of such ailment a ‘disease’?
(c)If the ailment or aggravation of such ailment is a disease, was it contributed to, to a significant degree, by the applicant’s employment by the Commonwealth?
SOME RELEVANT FACTS
The applicant was employed by the Department of Foreign Affairs and Trade as and from July 2004. He was transferred to Kandahar, Afghanistan in 2008. He stated that initially the intended term of the deployment was to be for a period of 3 months. Subsequently, however, the deployment was extended several times so that he served in Afghanistan for approximately nine months from 4 March 2008 until 4 November 2008.
He described being accommodated at and working from a multinational military facility situated at the Kandahar Airfield. This was, he explained, his primary workplace known as “Camp Baker”. It was a facility that was occupied primarily by uniformed members of the Australian Defence Force, liaison officers from other supporting agencies and civilians including himself. His accommodation was in an immediately adjacent site which was known as the ‘DST compound’. He described walking every day “next door” from the DST compound to Camp Baker where he carried out his work.
The applicant described, when in the witness box, that his time in Afghanistan was marked with repeated gastrointestinal infections. He went so far as to say that there were few times during his deployment when he wasn’t affected by what he described as an acute gastro- infection. He described the condition as extremely common during that time. He went so far as to say the condition experienced by him was continuous throughout the year of 2008.
In his evidence he suggested that consumption of contaminated water may have been the cause of these gastrointestinal problems. In response to a question as to when he first formed the view that there might have been something wrong with the water he was using in Afghanistan, he replied that when he arrived there was discussion amongst all the people he encountered there about the problem. For some reason, as he described it, he did not have the luxury of drinking bottled water, which most people did who were posted to the Kandahar facilities. He had to drink local water. On two occasions his gastro-infections were so bad that he attended the United States military hospital to receive medical treatment.
In cross examination the applicant was taken to the contents of a statement he made on 3 December 2020 which was attached to his workers’ compensation claim form of the same date. Whilst it is true to say there is a brief reference to the applicant experiencing “gastrointestinal upset” and “stomach complaints” there is no reference anywhere in that document to the cause of any gastrointestinal (GI) conditions suffered by him with the causes of such condition being as a result of consumption of contaminated water. When this was put to him his response was that it wasn’t in his mind at the time he made the statement. He wanted treatment for his psychiatric issues. The statement was, he considered, designed to progress a case for liability for a diagnosed condition of PTSD and obtain treatment. It was also asked of him in cross examination whether in December 2020 he believed he had suffered some sort of IBS condition as a result of the water quality in Kandahar. His response was, “It wasn’t my primary focus at the time”.
The applicant described two traumatic events which consisted of two clearly serious assaults. It is not necessary for the purposes of these reasons to condescend to any particular detail about the assaults.
However, the first incident (described as the ‘first traumatic event’) involved other employees in the DST compound taking exception to the applicant reporting a matter concerning a stray dog to his superiors in Canberra. The other employees in the compound took exception to this and restrained the applicant one evening after work against his will and brought him into a location where other workers were drinking. Whilst the applicant was restrained the dog was encouraged by way of attack commands to attempt to attack the applicant. The dog attempted to obey these commands but was unable to give effect to them because it was restrained by a chain. However, it should be emphasised that the dog was almost within reach of the applicant. There is no doubt that the experience was totally unjustified and clearly traumatic for the applicant.
The second incident (described as the ‘second traumatic event’) occurred whilst other workers in the DST compound were drinking. The applicant was asked to join a ‘party’ which he declined. He was then subjected to various insults by reason of his refusal to join in. He then retreated to his room which was very small and described as being in the nature of a metal “pod”. When he attempted to sleep several of the other workers banged loudly on the metal walls of his room or pod disrupting his attempts to get to sleep. He was then taunted with demands to come out of his room. He did not comply with these demands. The employees, who it appears were probably intoxicated, then broke into the applicant’s room and dragged him out. They subjected him to simulated acts. He was threatened not to report these events to ‘Canberra’. Nonetheless, he did report the incident at the first available opportunity, but it is apparent that such report was not taken seriously. The applicant was told words to the effect that the other employees in the DST compound were, amongst other things, ‘letting off steam’ and that he should learn to ‘get along’ with the other employees. He considered that he had a gross lack of support from his superiors and described it in such terms as ‘fainthearted’. The applicant explained that he had several threats made to him to ‘keep quiet’ about some of the activities that occurred in the DST compound and that these threats exacerbated the effects of the first and second traumatic events upon him.
It is quite apparent that these events, quite understandably, had a serious impact on the applicant. For quite some years after his return to Australia the applicant although clearly disturbed by the events that he experienced in Afghanistan, described experiencing symptoms that included anxiety, insomnia and gastrointestinal upset. He stated that he endeavoured for many years to self-manage those symptoms. Also, he said that he received some assistance from his general practitioner who prescribed medication and treatments including sleeping tablets and medicine for stomach complaints.
Eventually, the applicant’s treating general practitioner Dr Brownstein referred the applicant to Dr Corbett in a letter of referral on 8 May 2020, for opinion and management for what was described as ‘persistent altered bowel habit and deranged liver function.’[3] In that letter of referral Dr Brownstein described the applicant as experiencing intermittent loose stools and bloating. No other symptoms were identified. In terms of past history, the only reference was to an influenza-like illness in 2019. She also recorded in that letter of referral that the applicant was seeing a psychologist for trauma secondary to deployment in Afghanistan and does feel that his symptoms may be partially related to stress.
[3] JTB 297.
Eventually, the applicant made a claim for compensation with the respondent on 3 December 2020. The claimed condition was for post-traumatic stress disorder (‘PTSD’) suffered as a result of his employment duties in Afghanistan. These symptoms were said to have been first noticed by him whilst he was working there in July 2008.
The applicant’s claim was accepted on 23 April 2021 for liability under s 14 of the SRC Act for a condition described as an “anxiety state”, the date of injury being deemed to be 3 September 2020. This injury was reclassified to PTSD from an anxiety state on 9 March 2022.
Subsequently, on 6 April 2022, the deemed date of injury for the condition of PTSD was changed by the respondent to 4 April 2018.
The applicant made a further claim for workers’ compensation on 6 May 2022 for IBS. He claimed that the cause of this condition was by reason of a combination of exposure to a protogen and triggered by long-term workplace psychological distress.
Eventually, the respondent made 2 determinations concerning the applicant’s workers’ compensation claims on 24 August 2022. The first of those determinations accepted liability for IBS as secondary to PTSD pursuant to s 14 of the SRC Act. The deemed date of injury was said to be 10 March 2020. In making this determination the Delegate of the respondent relied upon medical evidence provided to them by way of reports from the applicant’s treating general practitioners Dr Ryan and Dr Brownstein together with a further clinical note from Dr Corbett.
The second determination made 24 August 2022 denied liability to the applicant for the separate claimed condition of IBS. The applicant on 5 September 2022 sought reconsideration of the second determination. Upon reconsideration of the second determination by a delegate of the respondent it was affirmed on 25 October 2022.
Subsequently, a delegate of the respondent on 12 December 2023 undertook an ‘own motion’ reconsideration of the first determination made on 24 August 2022 pursuant to the discretion conferred upon it to do so in s 62 (1) of the SRC Act.
The result of the ‘own motion’ reconsideration of the respondent’s delegate was to revoke the determination dated 24 August 2022 which accepted liability for IBS under s 14 of the SRC Act and instead deny liability to the applicant under that section of the SRC Act.
In reaching the decision to deny liability the respondent’s delegate relied upon the report of Dr Sethi of 31 May 2023. The delegate relied upon the following conclusions expressed in Dr Sethi’s report as follows:
(a)The applicant’s IBS is constitutional;
(b)The length of time between deployment in Afghanistan and the onset of IBS means that events during the applicant’s deployment, including hygiene conditions and contaminated water did not play any causative role;
(c)A causative link between PTSD and IBS has never been established in the clinical trials;
(d)Dr Sethi disagrees with the opinion of Dr Corbett, that the applicant’s IBS was caused by infection, and notes Dr Corbett’s view is ‘at odds with widespread medical and scientific thinking’;
(e)Dr Sethi disagrees with the opinion of Dr Ryan, that the applicant’s IBS was most likely related to his PTSD.
It is from the respondent’s own motion decision of 12 December 2023 that the applicant seeks review in this Tribunal.
THE MEDICAL EVIDENCE
Dr Corbett
Unfortunately, Dr Corbett the applicant’s treating gastroenterologist did not give oral evidence at the hearing of the application. There were however several written reports from him that were tendered.
With respect to the evidence of Dr Corbett, the respondent’s lawyers informed the applicant by email on 17 December 2024 that it required him to be made available for cross examination if the applicant intended to rely upon his evidence.[4] That email also informed the applicant that if Dr Corbett were not made available for cross examination, the respondent would submit that little or no weight should be given to any opinions expressed by him. For reasons that will be apparent later the Tribunal largely accepts this contention on the part of the respondent.
[4] JTB 1027.
Following the applicant’s referral by Dr Brownstein to Dr Corbett on 8 May 2020, he had a consultation with Dr Corbett by means of “telehealth”. Following that telehealth consultation Dr Corbett sent a letter to Dr Brownstein on 20 May 2020.[5] That letter described the applicant’s symptoms. It also recorded that the applicant “wondered whether stress and certain foods exacerbate symptoms”. It also recorded the presence of Blastocystis and Dientamoeba. It summarises the applicant’s medical problems as, “Altered bowel habit-for investigation, presumed diarrhoea-predominant IBS and raised LFT’s -hepatocellular, presumed fatty liver.”
[5] JTB 469.
Dr Corbett conducted a colonoscopy on 2 June 2020. A colonoscopy report prepared by him on that day made a diagnosis, or identified the applicant having, a condition ‘consistent with IBS’.[6]
[6] JTB 282.
Following the colonoscopy performed by Dr Corbett on the applicant he sent a further letter on 28 July 2020 to Dr Brownstein.[7] The contents of that letter have been considered in their entirety. Dr Corbett observed that the applicant must address his weight gain at that time through diet and exercise. He further explained that he went through the pathogenesis, prognosis and management of IBS with the applicant. He summarises the applicant’s medical problems as being, “diarrhoea predominant IBS- Coeliac serology pending and presumed fatty liver-coeliac serology pending”.
[7] JTB 753.
Subsequently, Dr Corbett prepared a report on 26 August 2022 which was submitted to a delegate of the respondent.[8] The contents of that report are referred to in their entirety. It is not necessary to reproduce vast details of that report. However, it is appropriate to briefly refer to some of the matters touched on by him.
[8] JTB 258.
In the section of the report of 26 August 2022 entitled ‘Causation’, Dr Corbett opines that the cause for the applicant’s IBS is not known. He stated there was however a clear temporal relationship to his first lower gastrointestinal symptoms starting while serving in Afghanistan. Later in the report in the section entitled ‘Causal Connection’, he stated that there appears to be a temporal connection to episodes of probable infectious gastroenteritis whilst the applicant was serving in Afghanistan and that the ensuing intermittent GI symptoms that are compatible with postinfectious diarrhoea predominant IBS.
A further brief letter dated 30 August 2023 from Dr Corbett was in evidence.[9] That letter was produced following a review he contracted of the applicant on the same day. It also followed the receipt of the first report from Dr Sethi. That letter reported that the applicant clearly noted an acute gastroenteritis-like illness when serving in Afghanistan followed by ongoing GI symptoms. He stated that the diagnosis of IBS is clear. Further, he opined that the temporal association with this acute infectious illness makes postinfectious aetiology the most likely. He considered that there is absolutely no doubt that mental health including PTSD would play a significant role in the applicant’s ongoing IBS symptoms. Therefore, he stated that his original opinion remains unchanged.
[9] JTB 260.
Reference should also be made to two further documents from Dr Corbett. There is a file note dated 31 August 2022.[10] That file note records that he reviewed the applicant in his rooms on that day for the purposes of responding to specific questions raised from a recent medical report that had been requested by the respondent Comcare. Dr Corbett has noted that the applicant informed him that his symptoms which he had described as being present for at least eight years, had in fact begun when he was serving in Afghanistan. It was further noted by Dr Corbett that he understood, “then there were issues with the water supply quality. He described himself and colleagues developing episodic acute gastroenteritis illnesses with diarrhoea.” It was then recorded that since then the applicant had experienced ongoing intermittent symptoms that he usually self-managed with oral rehydration solution and Imodium, which he found of little benefit. Dr Corbett in that file note further recorded that symptom frequency is maximum at four times per week to once every 3-4 weeks. A handwritten clinical note of that consultation with Dr Corbett, presumably made by him, was also in evidence.[11]
[10] JTB 754.
[11] JTB 755.
Dr Sethi
There was also oral evidence from Dr Sethi and by way of two reports prepared by him on 31 May 2023[12] and 9 September 2024.[13] The contents of both of those reports prepared by Dr Sethi are referred to in their entirety and have been considered by the Tribunal. It is not necessary for the purposes of these reasons to reproduce significant portions of them. However, it is appropriate to record several matters contained in them.
[12] JTB 269.
[13] JTB 954.
In his first report of 31 May 2023 Dr Sethi provides a patient history. Amongst other things, in that section of his first report he records that the applicant claimed he drank contaminated water and subsequently developed IBS. It was recorded the applicant explained that he experienced diarrhoea, constipation later on and stomach upset. Importantly, for the purposes of this application, Dr Sethi also noted that the applicant claimed that his gastrointestinal symptoms commenced immediately after his 2008 deployment and that he suspected a psychological basis for his physical symptoms. Reference was also made to the applicant attributing these physical conditions to the worksite at Kandahar, in Afghanistan to which he was assigned in 2008.

Dr Sethi’s report of 31 May 2023 then had a section entitled ‘Opinion’. He expressed the opinion that the applicant developed IBS entirely independently of his employment and the deployment to Afghanistan and PTSD. These factors, he considered did not play any causative role. The opinion was expressed by him that the applicant’s IBS has occurred regardless. He then explained his reasons for reaching this conclusion.
It was noted by Dr Sethi that IBS is a very common condition affecting around 15-20% of the general population and is caused by visceral hypersensitivity of the gastrointestinal tract. This is, he stated accepted widespread medical and scientific opinion.
Dr Sethi then observed that the applicant’s general practitioner has reviewed him directly and taken a substantial medical history. He concluded that given the very long-time gap of several years between the applicant’s alleged exposure in Afghanistan and first reporting symptoms in 2020, the claimed diagnosis of postinfectious IBS is factually incorrect and should be disregarded. He concluded therefore, that the applicant has developed IBS of his own accord.
He further stated that in his opinion, the most probable cause was not an infection and it played no causative role whatsoever. It was also observed by Dr Sethi that Dr Corbett stated that postinfectious IBS cases will often spontaneously resolve.
Dr Sethi disagreed with Dr Corbett’s diagnosis of postinfectious IBS. He stated that Dr Corbett’s opinion is at odds with established widespread medical and scientific thinking, which is that IBS is predominantly caused by visceral hypersensitivity of the gastrointestinal tract. In his opinion Dr Corbett has given excessive and undue importance to the theory that the applicant’s IBS is infectious in etiology.
Also, Dr Sethi disagreed with Dr Corbett’s claims of a temporal connection to episodes of probable infectious gastroenteritis while serving in Afghanistan and the ensuing intermittent gastrointestinal symptoms. In Dr Sethi’s opinion they are entirely unrelated. Given that the applicant last served in Afghanistan over 15 years ago, it is unreasonable and improbable that this is to blame for the applicant’s current symptoms. In support of this conclusion, he noted that there was a very prolonged time gap of 12 years between 2008 when the applicant left Afghanistan and 2020 when he first sought medical attention. Therefore, he concluded this essentially rules out any causative role.
Dr Sethi then in his report of 31 May 2023 provided answers to a series of specific questions. Those answers incorporated the matters referred to above including the questions of causation and reiterated that in his opinion the applicant currently suffers from IBS related to his gastrointestinal health that has developed of its own accord, predominantly due to visceral hypersensitivity of his gastrointestinal tract. He reiterated also that it is accepted widespread medical and scientific opinion that this is the predominant cause of IBS.
It was also stated by Dr Sethi that the condition of IBS is not symptomatic of the applicant’s diagnosis of PTSD, with a date of injury of 4 April 2018. He also stated to no extent at all, did he consider the applicant’s consumption of contaminated water in Afghanistan in 2008 caused or contributed to any gastrointestinal condition.
In his second report of 9 September 2024 Dr Sethi was asked to respond to a series of specific questions contained in a letter of instruction from the respondent’s lawyers. That letter of instruction also contained additional documentation for his consideration including, amongst other things, two reports from Dr Corbett of 26 August 2022 and 30 August 2023 together with clinical records that had been summoned from the applicant’s treating general practitioners and gastroenterologists. The contents of the second report of Dr Sethi are referred to in their entirety. They need not be referred to in any significant detail.
Dr Sethi was asked whether he disagreed with the opinions expressed by Dr Corbett. He stated that he did disagree with such opinions and outlined his reasoning for doing so.
It was observed by Dr Sethi that on 20 May 2020 Dr Corbett reviewed the applicant and recorded, ‘wondered whether stress and certain foods exacerbate symptoms’. An 8-year history of altered bowel habit with abdominal discomfort and lose watery diarrhoea was noted. Dr Corbett opined that he, ‘presumably has diarrhoea-predominant irritable bowel syndrome.’
He then observed that Dr Corbett has essentially contradicted his own earlier claim. He noted, as had been observed previously, that the applicant did not report his symptoms until 2020, which is 12 years after his deployment to Afghanistan. This he observed, was a very prolonged time gap and essentially excludes any causative role. Had his deployment been causative or responsible, one would have reasonably expected his symptoms to have started soon afterwards.
In Dr Sethi’s opinion, the applicant’s symptoms resolved after 2008 and did not recur until 2020. This essentially disproves the applicant’s allegation of having developed postinfectious IBS.
Dr Sethi then referred to a clinical note made when the applicant presented to his general practitioner 10 March 2020. That note recorded ‘Presents with multiple physical symptoms. All increased when started doing CPT with psychologist-discussing issues around deployment to Afghanistan and trauma for this. Frequent insomnia. Intermittent upset stomach with loose stool/bloating. Not linked with particular foods. Mainly diarrhoea. No family history of bowel cancer. No vomiting/weight loss/blood in stool. Frequent headaches-slight a then a sharp pain-might last for a few hours. Muscle and joint pains. Feeling fuzzy.’
That clinical note in the opinion of Dr Sethi strongly indicates that the applicant’s gastrointestinal symptoms started in 2020 and not in 2008 as he claims.
In Dr Sethi’s opinion, the applicant did not report his symptoms for several years and now alleges they were present all along; however, he observed there is absolutely no objective evidence to back up such an assertion.
Dr Sethi agreed with Dr Corbett’s conclusion that the diagnosis of IBS is clear. He disagreed with Dr Corbett’s conclusion that the temporal association with such an acute infectious illness makes postinfectious aetiology the most likely. He reiterated that there is no temporal association between the acute infectious illness given the prolonged time gap, that he previously explained, of 12 years.
Dr Corbett’s opinion that there is absolutely no doubt that mental health including PTSD would play a significant role in the applicant’s ongoing IBS symptoms was disputed by Dr Sethi. He disagreed with this conclusion because in his opinion the vast majority of medical and scientific experts do not believe that any causative link exists between mental health disorders and IBS. Such a conclusion has never, he observed, been proven or established in the medical and scientific literature. Any suggestion of a causative link is highly speculative and highly unproven.
Dr Sethi was asked to comment to what extent (if any) is Dr Corbett’s opinion supported or contradicted by scholarly literature. Dr Sethi stated that Dr Corbett’s opinions are strongly contradicted by the literature. He noted that the vast majority of medical and scientific experts would not accept Dr Corbett’s opinion that mental health disorders cause or worsen IBS. In support of this contention, he attached to his second report three articles. Those articles have been read and considered by the Tribunal. For instance, in the first of those articles the learned authors express several opinions.[14] They stated that the hypersensitivity of the large intestines is a characteristic feature of all IBS subtypes because the amended rectal perception in 61% of IBS patients has been documented. They further stated that visceral hypersensitivity (‘VHS’) plays a key role in the pathogenesis of IBS. Similarly, the learned authors of the third article observe that VHS, or an increased perception of stimuli originating from the viscera, is a hallmark feature of IBS and is currently regarded as the main factor underlying abdominal pain in IBS patients. VHS entails both hyperalgesia and allodynia.[15]
[14] Dudzinska, Grabrucker, Kwiatowski, Sitarz and Sienkiewicz, “The importance of Visceral Hypersensitivity in Irritable Bowel Syndrome-Plant Metabolites in IBS Treatment." Pharmaceuticals (Basel); 16 (10).
[15] Deiteren, de Wit, van der Linder, De Man, Pelckmans, De Winter, “Irritable Bowel Syndrome and Visceral Hypersensitivity: Risk Factors and Patho-physiological Mechanisms." Acta Gastro-Enterologica Belgica, Vol LXXIX.
In response to another question put to him Dr Sethi noted that the applicant was recorded by Dr Corbett as weighing 105 kg on 30 August 2023. He considered that such a weight would lead to the applicant very likely being classified as obese. He also stated that obesity is well documented in the medical and scientific literature to lead to a worsening of IBS symptoms.
When giving his evidence from the witness box Dr Sethi adopted both the reports that he prepared as being true and correct.
He was then asked several questions concerning various articles concerning the causes of IBS that were relied upon by the applicant.[16] Dr Sethi stated that he had read each of those articles and considered them. After reading them he stated they had not caused him to change his opinions. These articles, the contents which need not be referred to for the purposes of these reasons, addressed the question of whether IBS is caused by stress.
[16] The articles are in Tabs A1 to A9 JTB.
Dr Sethi made several observations. He observed that the overwhelming majority of his peers would agree that stress does not cause IBS. Any link is speculative and entirely unproven.
Another reason relied on by Dr Sethi in the witness box for not changing his opinion after reading these articles is that one of them involved a study of PTSD on Vietnam war veterans. He was critical of this study because it was derived from a very small sample size. That sample size was only 300 persons. Additionally, he stated that the authors of that article acknowledged the sample size limits. Therefore, the conclusion according to Dr Sethi was highly speculative. He reiterated that at best this might be described as preliminary data which was not accepted by the vast majority of his peers. He also stated that in order to change his opinion it would require the production of multiple studies of an appropriate sample size to establish a causal association. He stated that what was relied upon by the applicant was essentially one study that was “cherry picking” and therefore not good clinical practice.
Several matters were touched on when Dr Sethi was cross examined.
In response to one series of questions Dr Sethi relating to inflammation from infections causing IBS (postinfectious IBS), he responded that if this were the case, treatment should have resolved it. Therefore, it could not be said it was a causative factor.
Dr Sethi was also asked how a doctor diagnosed IBS. He stated the following tasks were undertaken:
(a)History taking;
(b)Physical examination;
(c)Clinical synthesis; and
(d)Review of documentation.
It was suggested to Dr Sethi that it would not be possible to undertake a proper diagnosis by undertaking a file review alone. He disputed this suggestion. He emphasised that an overwhelming number of patients would not show or disclose IBS on a physical examination. With respect to patient history, he explained the main benefit is to ensure to the treating practitioner that the symptoms are consistent with IBS and not anything else. In terms of when one normally takes a patient history in the context of diagnosing IBS, Dr Sethi stated it depends on the context. If it were in his rooms or a hospital he would. If it was a file review or for medicolegal reporting purposes he would not.
Further, when challenged about how he prepared his reports, he stated it was perfectly appropriate to make a diagnosis, as he did in this case, on a file review. The reason he explained for reaching this conclusion was because the applicant had undergone a colonoscopy and IBS was diagnosed by Dr Corbett which he accepted. This is perfectly understandable.
Dr Sethi was then asked what causes IBS. In summary he stated the following:
(a)It is usually caused by visceral hypersensitivity of the gastrointestinal tract. This means the gut starts to send signals to the brain when it should be ignoring them. Those signals are painful.
(b)Dysmotility of the bowel.
(c)Increased body weight or obesity.
(d)Smoking can be a contributing factor.
(e)It tends to be more prevalent in women.
Dr Sethi was then asked about stress as a contributing factor. He stated that he does not believe that stress causes IBS. He stated that stress is blamed for numerous conditions in medicine. This is, he said, highly speculative and entirely unproven. He also stated that he had been in clinical practice since 2006 and had not found a link between PTSD or stress as a causative factor in the onset of IBS. It was emphasised by Dr Sethi that speaking to his colleagues they reached a similar conclusion.
He was also asked about whether infection causes IBS. He stated that he did not consider it is proven that it is a cause of IBS. In this context he stated that in the applicant’s case it was approximately 12 years since him being in Afghanistan and the onset of his conditions. For this reason, he considered that the applicant’s service in Afghanistan was irrelevant to his case. On several occasions in cross examination when pressed on this topic he reiterated that he did not believe that the applicant’s service in Afghanistan caused the onset of his IBS. He repeated that there was a long-time gap between his service and onset of the symptoms.
The role of visceral hypersensitivity was then again canvassed in cross examination of Dr Sethi. He reiterated that he considered this was the cause of IBS. He readily conceded that the exact mechanism of visceral hypersensitivity has not been fully worked out. He repeated that it is strongly considered that the brain starts to send signals that the gut is painful, that it should be ignoring. This information he emphasised was based upon accumulated scientific opinion over a number of years of research. He explained that IBS is not an organic disease it is a functional abnormality. That is why it is not reasonable to blame it on stress.
This conclusion Dr Sethi opined is subject to widespread acceptance and there is no doubt in his opinion, that it is strongly established in the literature. He conceded it is a working theory that is widely accepted. He also emphasised that this opinion is accepted by the overwhelming majority of his peers. This is not the case he stated with respect to stress as a cause of IBS. He agreed with the suggestion that visceral hypersensitivity is the “strongest candidate” for a cause of IBS.
In response to another question in cross examination, Dr Sethi stated that he was not aware of any genetic role in contracting visceral hypersensitivity. He did say however, by reference to one of the articles that was in evidence before the Tribunal, that visceral hypersensitivity is multifactorial.
Extracts from several video presentations given by Dr Sethi were put to him by the applicant in cross examination. Those videos have been considered by the Tribunal. One of those videos considered the question of stress as a contributing factor to IBS. Dr Sethi stated that patients frequently will inform a treating practitioner that they have worse symptoms of IBS when under stress. He stated this may be an association but not a cause or effect.
CONSIDERATION
Introduction, some observations concerning the witnesses who gave oral evidence
The applicant
At the outset, it is appropriate to make some comments concerning the witnesses who gave oral evidence at the hearing of this application.
The applicant, who represented himself, gave comparatively extensive evidence. Some of it was very much in the nature of submissions. Given that the applicant was self-represented and is not legally qualified the Tribunal was prepared to permit his evidence to follow this course which might not otherwise have been the case. Mr Davidson who appeared for the respondent did not object to this approach. He is to be commended for the consideration.
There is no doubt that the applicant is clearly suffering from the effects of his accepted condition of PTSD. This should be, and was, taken into account when assessing his evidence. To the applicant’s complete credit, both in response to questions in cross examination and early on in his closing submissions, he readily conceded that his recollections of many events were not that great. The Tribunal observes that the applicant’s service in Afghanistan has clearly had its lasting effects upon him. This is unfortunate.
Dr Sethi
With respect to the evidence of Dr Sethi some initial observations should be made. In both cross examination and closing submissions the applicant was highly critical of Dr Sethi and the opinions he expressed, both in his written reports, evidence in chief and cross examination. It was contended by the applicant, amongst other things, that the Tribunal should disregard the opinions he expressed.
There were several reasons for this advanced by the applicant. They included that Dr Sethi is not an expert in medical research, that he had adopted a “pet theory” that was not published anywhere, that at best he was an expert who can only give evidence about treatment of IBS and not the cause, as he is not an expert in causation and that finally he had strayed into the role of advocacy rather than that of an independent expert. It was contended that Dr Sethi’s theory was unsupported, and particularly more so than the conclusions reached by other doctors.
The Tribunal did not see the evidence given by Dr Sethi, both in his reports and from the witness box, in the way submitted by the applicant. Insofar as he expressed professional opinions the Tribunal is satisfied that they were genuinely held professional opinions reached on a rational basis. He is a vastly experienced gastroenterologist who has had approximately 20 years of clinical practice. In reaching the conclusions that he did he also observed that such opinions accorded with the majority of his peers and contained in much published material. He did not, as contended for by the applicant, stray into or adopt the role as an advocate for the party who called him as a witness.
It appeared to the Tribunal that he properly understood his role as an expert witness which is to assist the Tribunal in its endeavours to reach the correct and preferable decision. Also, a feature of his evidence which the Tribunal found to his credit, was that although he expressed the professional opinion that the applicant developed IBS of his own accord predominantly due to visceral hypersensitivity of the gastrointestinal tract, he conceded quite properly in cross examination that there is no certainty of this condition being a cause. He emphasised that he reached this conclusion because that theory or hypothesis is the one that the majority of the body of expert medical opinion considers the most likely cause. It also accorded with his observations from almost 20 years of clinical practice. Such a concession is the hallmark of a candid and fair witness. This is the impression the Tribunal formed of Dr Sethi.
Also, in terms of Dr Sethi’s evidence, it should be recalled that there was no other medical witness called to give evidence at the hearing of the application who specifically presented a diametrically opposed opinion to him. Had that been the case the Tribunal would have been placed in a better position to determine whether to prefer his evidence over any other expert evidence.
The applicant’s IBS condition

It should be acknowledged, lest there be any doubt, that both Dr Corbett and Dr Sethi agree that the applicant suffers from IBS.[17] The Tribunal accepts this diagnosis.
[17] Dr Corbett JTB 258 and Dr Sethi JTB 276.
There are alternative theories or hypotheses concerning the possible causes or aggravation of the applicant’s diagnosed condition of IBS.
The Waterborne Disease Theory
The first of these theories was described by counsel for the respondent as the “Waterborne Disease Theory”. This is a helpful description. In short it was suggested that the applicant suffered his gastrointestinal illness as a result of contaminated water that he drank or was otherwise exposed to in Afghanistan.
The respondent contended, and the Tribunal agrees, that the problem with advancing this theory or hypothesis is that no doctor positively subscribed to or advanced such a theory. Dr Sethi steadfastly denied that on the facts before him this was a possible cause.[18]
[18] In addition to his evidence on this topic when in the witness box this contention was recorded in paragraph 4 of his report of 31 May 2023. (JTB 278).
Whilst Dr Corbett did not give oral evidence as noted earlier, there were several letters, reports and file notes created by him in evidence. The most detailed report of 26 August 2022 prepared for the respondent in the section entitled “Causation” states that the cause of the applicant’s IBS is not known.[19] He then refers to a clear temporal relationship between the applicant’s first lower gastrointestinal symptoms starting while he served in Afghanistan. That is consistent with other evidence.
[19] JTB 258.
Indeed, in a short letter of 30 August 2023 Dr Corbett states that the temporal association with the acute infectious illness makes postinfectious aetiology the most likely cause without reaching a conclusion.[20]
[20] JTB 260.
In a file note dated 31 August 2022 recorded by Dr Corbett following his review of the applicant on that day in his rooms, it records Dr Corbett noting that there were issues with the water supply quality when the applicant was serving in Afghanistan. It was also recorded by Dr Corbett that the applicant described him and his colleagues developing episodic acute gastroenteritis illnesses with diarrhoea. Nowhere in the material does Dr Corbett specifically state that contaminated water has caused the applicant’s IBS.
Another problem arising from the contaminated water theory is that it does not fit the usual pattern of postinfectious IBS. Such a condition was said by Dr Sethi to come on immediately and is acute. There was no evidence of such symptomology before the Tribunal.
The applicant conceded that his symptoms were more isolated. In cross examination the applicant stated the best way of describing his condition was “relapsing and remitting”. He further explained that this cycle occurred when there would be some times when his stomach didn’t trouble him and other times when he felt unwell and had to seek treatment. These symptoms included tenderness in his stomach area, which could not be touched without him experiencing extreme discomfort.
Indeed, in some of the clinical notes the conditions experienced by the applicant corroborated his evidence. A clinical note made by Dr Brownstein of a consultation on 10 March 2020 recorded the applicant experiencing, amongst other things, an “intermittent upset stomach”.[21] In one note made by Dr Ryan in June 2022 the condition was said to be “relapsing/remitting”.[22] In a letter to the respondent of 10 May 2022 the applicant explained that upon his return to Australia from Afghanistan, the gastrointestinal symptoms he experienced became less severe and would “flareup” from time to time and that could be managed with over-the-counter medicines.[23] He further stated that such symptoms developed over time particularly between 2018-2020. Such conditions considerably worsened from 2020 onwards. This is not indicative of postinfection IBS.
[21] JTB 783.
[22] JTB 511.
[23] JTB 839.
Another problem with the Waterborne Disease Theory identified by the respondent, with which the Tribunal agrees, is that there is simply no evidence of a significant pathogen, let alone any pathogen, based upon a source of poor water quality. In evidence before the Tribunal was a copy of an email sent by Major Shepley 12 April 2008.[24] The applicant stated he did not receive this email. He said he obtained a hard copy of the email from one of the other military members living at Camp Baker. It states, amongst other things, that the Camp Baker water supply had been tested and found to contain “protogens” described by him in that email as “bad stuff” well above acceptable levels. There does not appear to be a commonly used word “protogens”. It is more probable than not that when Major Shepley used the term “protegens” he meant pathogens. Whatever was meant by this email, it does not prove anything concerning the contaminated water supply and certainly does not assist in establishing that the applicant’s consumption of contaminated water in Afghanistan was the cause of the applicant’s IBS.
[24] JTB 841.
Reference should also be made to a specimen collected from the applicant on 16 April 2020.[25] That records the presence of dietamoeba fragilis and blastocystis hominis. Dr Sethi in his report of 31 May 2023 records that they were unlikely acquired in Afghanistan and on the balance of probabilities elsewhere. He noted that these pathogens are also very common in Australia.[26] Based on this evidence the Tribunal cannot conclude that such pathogens were contracted in Afghanistan when the applicant served there.
[25] JTB 728.
[26] JTB 276.
PTSD or stress-related factors as a cause
The second theory is that the applicant’s diagnosed condition of PTSD or stress-related factors are the cause of the IBS suffered by him.
There are several problems or obstacles in accepting this theory as a probable cause of the IBS condition suffered by the applicant.
Once again, neither of the gastroenterologists support such a finding. In the summary of Dr Sethi’s evidence referred to above he was adamant that PTSD was not the cause of the IBS suffered by the applicant. That summary is referred to and repeated. Amongst other things he reached this conclusion based upon his almost 20 years of clinical practice, the predominant view of his gastroenterologist peers and based upon his review of the literature.
In the witness box he emphasised that IBS is not an organic disease, it is a functional abnormality. That is why, he explained it is not reasonable or appropriate to blame the condition on or conclude that it is caused by stress.
Dr Corbett, on the other hand did not advance a hypothesis or theory that stress, or PTSD caused the applicant’s IBS. It should be repeated that in the lengthiest report prepared by him dated 26 August 2022 under the section entitled “Causation” he stated that the cause of the applicant’s IBS is not known.[27] The high point, if it can be called that, of his opinions on this topic is contained in his letter of 30 August 2023 where he goes so far to state that there is absolutely no doubt that mental health including PTSD would play a significant role in the applicant’s ongoing IBS symptoms.[28] To the extent that Dr Corbett advances a hypothesis or theory of the causes of the applicant’s IBS, it is in that brief report said to be the temporal association with the acute infectious illness making postinfectious aetiology the most likely.
[27] JTB 258.
[28] JTB 260.
Reference should also be made to a brief report prepared by the applicant’s treating general practitioner from time-to-time, Dr Ryan. He prepared a report of 13 June 2022.[29] Insofar as that report purports to state that the applicant’s symptoms developed in the year 2020, that report is incorrect. He briefly opines in that report that the most likely cause of the applicant’s IBS is due to PTSD. The evidence of the applicant was that he had experienced these conditions for quite some time prior to presenting in 2020. The Tribunal accepts the respondent’s submission that no weight should be attributed or attached to Dr Ryan’s views.
[29] JTB 264.
Brief mention should be made of another problem concerning the theory that the applicant’s IBS has been caused by his diagnosed condition of PTSD. That problem is that the medical literature that was in evidence before the Tribunal does not support such a contention. It is at best equivocal. Dr Sethi described the consideration of the question in the literature, such as it was, before the Tribunal at best as emerging, highly speculative and unproven. In his evidence he was taken to most of the articles and asked for his comments or opinion on them with respect to this question. By way of response not only did he emphasise the speculative and unproven nature of such a theory or hypothesis but also quite carefully identified inherent limitations in the literature concerned. The Tribunal has no reason to doubt this evidence from Dr Sethi and accepts it. In giving his evidence on this topic, the Tribunal considers he brought a considered mind and engaged in a rational and genuine reasoning process in reaching the conclusions that he did.
There is another, or third, problem that emerges from a practical consideration of the theory or hypothesis that PTSD contributed to the applicant’s condition of IBS. On the evidence before the Tribunal, it is just not possible to correlate the applicant’s experience of his PTSD symptoms and the experience of gastrointestinal symptoms. In short, correlation cannot be equated with causation.
There are several key periods that should be taken into account. In 2016 the applicant described his psychological or mental health conditions as becoming “unmanageable” rather than any gastrointestinal symptoms. As was contended for by the respondent, during this time span largely until he presented to Dr Brownstein in 2020, there is a divergence between the psychiatric symptoms than the gastrointestinal symptoms. In the scheme of things, the applicant described relative stability with respect to his gastrointestinal symptoms during that time, as opposed to a comparative increase or deterioration in his mental health conditions. In short, there was not a matching escalation between the two conditions concerned. This is not indicative of the applicant’s PTSD being causative of his IBS.
In the early part of 2020 when the applicant commenced cognitive behavioural therapy with Ms Maloney a psychologist to whom he was referred by the Employee Assistance Program of his employer. In discussions with her issues arising from his deployment to Afghanistan and the trauma arising from it, as recorded in the clinical note of Dr Brownstein of her consultation with the applicant on 10 March 2020 were addressed. It is apparent from both clinical notes made of consultations he had at that time with his treating general practitioners and from his own evidence, that there was a clear correlation between the psychological and gastrointestinal conditions as and from that time. It was indeed, the deterioration of his gastrointestinal symptoms, or perhaps the increasing frequency of them that led to his referral to Dr Corbett.
The applicant was referred by the respondent to Dr Chambers a consultant psychiatrist, who conducted an assessment of the applicant on 8 June 2021. Dr Chambers prepared a report following that assessment.[30] Although that report prepared by Dr Chambers was clearly for the purposes of assessing the applicant’s mental health claims, in particular PTSD, it does contain observations that are relevant to and shed light on the subject matter of this application.
[30] JTB 287.
Naturally, the contents of Dr Chambers’ report are referred to in their entirety. In the section entitled “History of Relevant Issues” Dr Chambers has recorded that the applicant stated he sought assistance in Afghanistan for gastrointestinal symptoms which he thought were related to his anxiety at that time. Further, in the same section, Dr Chambers has recorded that when the applicant returned from Afghanistan he continued working and he reported that between 2009 and 2014 he felt “relatively normal” and was working full time and there were no particular triggers of the events. One pauses to observe that this notation by Dr Chambers based upon what he says the applicant informed him at the time of the assessment is difficult to reconcile with the applicant’s evidence in cross examination to this Tribunal in the hearing of this application that he continued to experience regular gastroenterological upsets throughout that time. The upsets he described could not be in any way categorised objectively as “relatively normal”.
This part of Dr Chambers’ report also assumes significance because nowhere in the history recorded by him is any reference made to the applicant informing him that he suffered gastrointestinal problems as a result of drinking contaminated water in Afghanistan. Given the applicant’s subsequent evidence on the topic it is surprising he did not do so.
Dr Chambers then records that in 2014 there was a trigger of previous traumatic events when there was an investigation in the workplace in relation to events that had occurred in Afghanistan. He further recorded that at that time the applicant sought treatment from his general practitioner for his gastrointestinal systems. One must observe that there was no evidence before the Tribunal of any such treatment being sought by the applicant from his general practitioner for gastrointestinal symptoms at that time. Presumably, had such treatment been sought, clinical notes from that treating general practitioner would have been obtained, and if necessary that doctor or doctors called to give evidence before the Tribunal to corroborate the applicant’s account, not only as he gave it to this Tribunal but also to Dr Chambers.
In a further section of his report entitled “Current Symptoms” Dr Chambers has gone into some detail as to what symptoms the applicant has experienced. There is no reference in that section of Dr Chambers’ report to the applicant experiencing any gastrointestinal symptoms. This is surprising, given that the applicant presented as someone who was careful, conscientious and alive to protecting his own interests. One would have expected that were gastrointestinal symptoms being experienced by the applicant with the frequency and effect that he described for all those years after his return from Afghanistan, an accurate description would have been furnished to Dr Chambers and significant emphasis placed upon them and the effect that they had when his patient history was being taken. When probed on this issue in cross examination the applicant stated that Dr Chambers’ focus was to take a general picture. He reiterated; that Dr Chambers had been asked about the applicant’s psychiatric symptoms in June 2021. The applicant further stated that he did not recall specifically if he had any gastrointestinal symptoms at that time. When probed further he stated that he didn’t recall having gastrointestinal symptoms at that time. Notwithstanding this explanation by the applicant on these questions, once again, the Tribunal finds his response to this line of cross examination difficult to accept if he had indeed been experiencing gastrointestinal difficulties to the level he described in his evidence over many years. In short it would have been expected that the applicant might have been broadcasting these facts like a very bright beacon on a dark night. It is telling that he did not do so.
In the section of Dr Chambers’ report concerning “Current Medication and Treatment” there is no reference to the applicant taking anything for his gastrointestinal conditions.
There is another aspect of the evidence that the Tribunal finds to some extent corroborates or confirms its views about the applicant’s evidence over what gastrointestinal symptoms he experienced from the time that he left Afghanistan until much later, most likely 2014 as contended for by Dr Sethi.
Another possible contributing factor to the applicant’s IBS
Dr Sethi also made a further observation in his supplementary report of 9 September 2024 that the applicant was recorded by Dr Corbett as weighing 105 kg on 30 August 2023.[31] This would very likely in Dr Sethi’s opinion classify him as obese. He observed that it is well documented in the medical and scientific literature that such a condition will worsen IBS symptoms.
[31] JTB 959.
This observation made in his supplementary report was reiterated by Dr Sethi when he was in the witness box. He stated that given the weight of the applicant recorded by Dr Corbett he would be considered to be obese. He emphasised that body mass is referred to in the medical literature both in terms of causation and worsening the symptoms of IBS. He emphasised that increased bodyweight or obesity can do both. He also stated it does not matter what the cause of the weight increase is, it indicates that it can contribute to the IBS condition. The Tribunal has no reason not to accept his evidence from Dr Sethi.
Inflammation from infections causing IBS (postinfectious IBS) and possible treatment
This question was briefly touched on by Dr Corbett in two of his reports that have already been referred to earlier in these reasons. In part 5, “Causal Connection” of his report of 26 August 2022 Dr Corbett stated there appears to be a temporal connection of episodes of probable infectious gastroenteritis while serving in Afghanistan and the ensuing intermittent GI symptoms that are compatible with postinfectious diarrhoea predominant IBS.
In his brief report of 30 August 2023 Dr Corbett reiterated that the applicant noted an acute gastroenteritis-like illness when serving in Afghanistan followed by ongoing GI symptoms. He states there is a clear diagnosis of IBS. That is not in dispute in this matter. He then opines that the temporal association with this acute infectious illness makes postinfectious aetiology the most likely.
Dr Sethi was probed on this when he was in the witness box. Clearly, he disagreed with Dr Corbett’s opinions. He was also referred to a small section of a learned article on the topic.[32] It was suggested to him that the extract from that article cited supports an opinion that there is no proof that using an anti-inflammatory is effective in the treatment of postinfectious IBS. It was suggested that the view remains speculative. He strongly disagreed with this suggestion. If there was, his stated gastrointestinal inflammation from infections causing IBS, on the contrary treatment of the IBS with an anti-inflammatory would enable one to reason that information in a postinfectious IBS environment is not causing the gastrointestinal symptoms as the treatment should have resolved it.
[32] JTB 116, American Journal of Gastroenterology, Vol 1, Issue 1, July 2012, Collins, Chang and Mearin, “Postinfectious Chronic Gut Dysfunction: From Bench to Bedside".
Also on that topic, Dr Sethi observed that Dr Corbett in his report of 26 August 2022 recorded that postinfectious IBS will often spontaneously resolve which he agreed with. This is in addition to any anti-inflammatory treatment that might be administered.
The views of Dr Sethi on this topic were not challenged by any other expert evidence, in particular that of Dr Corbett. In both the reports of Dr Corbett referred to, he has reached a conclusion or expressed an opinion without laying the appropriate evidentiary or other rational foundation for reaching that conclusion. There is an absence of reasoning process.
Visceral hypersensitivity of the applicant’s gastrointestinal tract
Details of the evidence provided by Dr Sethi in both of his reports and from the witness box concerning this question have been recounted earlier in these reasons. Those matters are referred to and repeated for the purposes of considering this possible cause of the applicant’s diagnosed IBS condition.

It should be briefly repeated that Dr Sethi considers that the applicant’s IBS condition developed of its own accord predominantly due to visceral hypersensitivity of the gastrointestinal tract. He has explained that this diagnosis is widely accepted in medical and scientific opinion and literature as the predominant cause for IBS. Additionally, Dr Sethi relied upon his approximately 20 years of clinical experience together with the majority view held by his peers.
The possibility that visceral hypersensitivity of the gastrointestinal tract may be the cause of the applicant’s IBS condition was not considered in any of the material produced by Dr Corbett. There is no contrary expert medical opinion that challenges those opinions and conclusions reached by Dr Sethi. As already noted, the Tribunal considers that the opinions expressed by him were genuinely held after carefully considering several matters including, the views of his peers, his considerable clinical experience and the existing state of the literature. There is no reason for the Tribunal to reject Dr Sethi’s evidence.
Also, to his credit, when challenged on his opinion that the applicant’s IBS condition was predominantly due to visceral hypersensitivity of his gastrointestinal tract, he conceded that accepting it causes IBS the exact causes of visceral hypersensitivity and its exact mechanism still has not been fully worked out. He agreed with a suggestion that it is the “strongest candidate” when it comes to a cause of the condition. This concession appropriately made by Dr Sethi is also a factor that has been taken into account by the Tribunal in concluding that his evidence was given for the purposes of genuinely assisting the Tribunal as a responsible expert witness should.
Did the applicant’s PTSD or stress aggravate his IBS condition?
The remaining question for the Tribunal to consider is whether the applicant’s PTSD or stress aggravated his IBS condition. Of course, in this consideration if the IBS condition arose separately from his work environment, it has to be determined whether such condition was aggravated to a significant degree by his employment. The Tribunal concludes that it did not.
In reaching this conclusion much of the analysis previously undertaken in these reasons equally applies. As contended for by the respondent the pattern of the symptoms of the applicant’s PTSD or psychological conditions don’t fit those of the IBS. The peaks of the PTSD and the IBS do not follow a pattern or otherwise correlate as observed above.
Further, as has also already been explained the medical evidence does not support a contention that the applicant’s employment in Afghanistan aggravated his IBS condition. Firstly, there is the evidence of Dr Sethi on this topic, referred to above, which has been accepted by the Tribunal. It should be repeated that he categorically rejected the suggestion that stress or PTSD can aggravate IBS. He was quite adamant that there is no such connection.
The closest that any medical practitioner really comes to making such a link is that of Dr Corbett in his very short supplementary report of 30 August 2023. It will be recalled he stated that there is absolutely no doubt that mental health including PTSD would play a significant role in the applicant’s ongoing IBS symptoms. Although he did not give evidence and have the opportunity to amplify or explain in more detail this opinion and the grounds for reaching it, the Tribunal concludes that Dr Corbett meant in that context an exacerbation or aggravation of the applicant’s symptoms. However, notwithstanding the opinion expressed by Dr Corbett concerning the significant role mental health including PTSD would play with respect to the applicant’s ongoing IBS symptoms, it is also apparent from reading that short report that he considers or prefers the postinfectious IBS theory. He considers it the most likely.
Unfortunately, because Dr Corbett did not give evidence the Tribunal has no explanation as to why he holds the particular views he does. There is no discussion or analysis in his reports of the cause and effect as between PTSD and ongoing IBS symptoms. There is no analysis of the learned medical literature which might support the opinions expressed, or conclusions reached by Dr Corbett, as best the Tribunal is able to interpret them. Additionally, there is no discussion, consideration or real analysis of the evidence before Dr Corbett that explains why he reaches the opinions he does with respect to the contribution of mental health conditions including PTSD to the IBS symptoms of the applicant. Unfortunately, the Tribunal has to accept the contention of the respondent that given the limited material before it, Dr Corbett’s opinions are largely unsupported, and the Tribunal is left “floating in space”. Given the paucity of analysis the Tribunal accepts a contention of the respondent that it should reject Dr Corbett’s evidence, insofar as it is admissible, on that question.
CONCLUSION
It is appropriate at this juncture to emphasise that the Tribunal must be fully informed of the reasoning process deployed in arriving at an expert’s opinions. An expert report or an opinion expressed by an expert without an adequate explanation of its foundation is accorded very little weight.[33] It also underlines the importance of the principle that an expert witness must identify the facts assumed in their opinion.[34] The absence of any adequate reasoning process or explanation relied on by Dr Corbett in reaching the opinions that he expresses in the reports, letters and file notes in the evidence, unfortunately means that very little weight can be placed upon those opinions expressed in them. It is another reason why the Tribunal prefers the evidence and opinions expressed by Dr Sethi.
[33] Makita (Australia) Pty Ltd v Sprowles (2001) 52 NSWLR 705.
[34] Arnotts Ltd & Ors v Trade Practices Commission (1990) 97 ALR 555 at 590.
Therefore, the Tribunal accepts the contention that at the end of the day all we are left with is speculation. It is true to say that the causes of IBS on the material before it are far from clear. It is fair to say the applicant’s condition traverses many years. The evidence simply does not permit the Tribunal to reach a positive state of satisfaction that his employment in Afghanistan contributed to the condition to a significant degree. The Tribunal was referred to the observations of Senior Member McCabe in Robinson and Military Rehabilitation and Compensation Commission.[35] It is really a matter of speculation.
[35] [2006] AATA 506 at [26].
Therefore, by reason of the foregoing matters the Tribunal concludes that whether or not the applicant suffers from an ailment or an aggravation of an ailment and is otherwise a disease by reason of the diagnosed condition of IBS such condition was not contributed to, to a significant degree, by his employment by the Commonwealth.
As such, the reviewable decision is affirmed.

Date(s) of hearing: 16, 17 April 2025

Advocate for the Applicant: Self-Represented

Solicitor for the Respondent: Jamie Watts

Date(s) of hearing:	16, 17 April 2025
Advocate for the Applicant:	Self-Represented
Solicitor for the Respondent:	Jamie Watts