Diemar v Simon Park Pty Ltd

DETERMINATION OF APPEAL PANEL
CITATION:	Diemar v Simon Park Pty Ltd [2023] NSWPICMP 423
APPELLANT:	Melinda Sadie Diemar
RESPONDENT:	Simon Park Pty Limited
APPEAL PANEL
MEMBER:	Marshal Douglas
MEDICAL ASSESSOR:	Douglas Andrews
MEDICAL ASSESSOR:	Michael Hong
DATE OF DECISION:	30 August 2023
CATCHWORDS:	WORKERS COMPENSATION - Workplace Injury Management and Workers Compensation Act 1998; assessment of permanent impairment from psychological injury; whether Medical Assessor (MA) erred and made assessment based on incorrect criteria by making a deduction under section 323(1) of 50% for pre-existing condition; whether MA erred by misdiagnosing appellant’s injury; whether MA erred and made assessment based on incorrect criteria by not applying clause 11.10 of Guidelines when assessing the deduction to be made under section 323(1) for appellant’s pre-existing condition; Held – Appeal Panel found that it was open to MA to make the diagnosis he did of appellant’s injury; the Appeal Panel found clause 11.10 of the Guidelines could not be engaged in this matter; the Appeal Panel found that the MA did not err or did not apply incorrect criteria when assessing the deduction to be made under section 323(1) for appellant’s pre-existing condition was 50%.

BACKGROUND TO THE APPLICATION TO APPEAL

On 8 June 2023 Melinda Sadie Diemar, the appellant, lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by
Dr Clayton Smith, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on 23 May 2023.
The appellant relies on the following grounds of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (1998 Act):
·        availability of additional relevant information (being additional information that was not available to, and that could not reasonably have been obtained by, the appellant before the medical assessment appealed against);
·        the assessment was made on the basis of incorrect criteria, and
·        the MAC contains a demonstrable error.
The delegate is satisfied that, on the face of the application, at least one ground of appeal has been made out. The Appeal Panel has conducted a review of the original medical assessment but limited to the ground(s) of appeal on which the appeal is made.
Rule 128 of the Personal Injury Commission Rules 2021 (PIC Rules) and Procedural Direction PIC7 - Appeals, reviews, reconsiderations and correction of obvious errors in medical disputes set out the practice and procedure in relation to the medical appeal process under s 328 of the 1998 Act. An Appeal Panel determines its own procedures in accordance with r 128(1) of the PIC Rules.
The assessment of permanent impairment is conducted in accordance with the SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4^th ed
1 March 2021 (the Guidelines) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5^th ed (AMA 5).

RELEVANT FACTUAL BACKGROUND

In October 2012 the appellant commenced employment as an oral health therapist with Simon Park Pty Ltd, the respondent. The respondent conducts dental surgeries at Medowie and Taliba Bay. In a statement the appellant signed on 15 January 2020 she says that
Mr Simon Park is the sole owner and principal dentist of the respondent. Due to trauma the appellant experienced from Mr Park during the course of her employment until late 2019 the appellant suffered a psychological injury.
Psychiatrist Dr Russel Davies provided a report dated 14 August 2020 to the appellant’s solicitors regarding various matters relating to the appellant’s injury, which included a part titled “Assessment of whole person impairment”, and in which Dr Davies assessed the appellant had an overall permanent impairment of the order of 22% whole person impairment (WPI). He also wrote that there was to be a “deduction for pre-existing impairment” of 10%=2.2% provides final WPI rounded up from 19.8 to 20% WPI”. The diagnosis Dr Davies made of the appellant’s injury was post-traumatic stress disorder.
Relying on that report the appellant’s solicitors wrote to the respondent’s insurer on
27 August 2020 advising it that the appellant claimed compensation of $51,780 under s 66 of the Workers Compensation Act1987.
Thereafter, psychiatrist Dr Peter Whetton examined the appellant on 15 October 2020 at the request of the respondent’s insurer. In a report dated 19 October 2020 Dr Whetton expressed the view that the appellant’s diagnosis was uncertain apart from the fact that she presented as mentally ill. Dr Whetton said that the bulk of her symptoms are best conceptualised as a major depressive disorder and that a possible underlying psychotic illness could not be excluded. Dr Whetton advised that the appellant had not reached “maximum medical improvement” and that “WPI cannot be assessed”. On 1 December 2020 the respondent’s insurer wrote to the appellant advising her that based on Dr Whetton’s report of 19 October 2020 the degree of her permanent impairment resulting from her injury was not currently capable of assessment because maximum medical improvement had not yet been reached.
The appellant then registered with the Commission an Application to Resolve a Dispute (ARD) dated 8 December 2020 seeking determination of her claim for compensation for permanent impairment under s 66 of the 1987 Act.
The matter was referred to Medical Assessor Nicholas Glozier to assess the medical dispute between the parties regarding whether the degree of permanent impairment of the appellant is fully ascertainable and, if so, the degree of her permanent impairment resulting from her injury. Medical Assessor Glozier examined the appellant on 7 April 2021 and in a MAC dated 16 April 2021 expressed the view that the appellant had not achieved maximum medical improvement relating to the injury she suffered, which he diagnosed was recurrent major depressive disorder. Medical Assessor Glozier, consistent with s 322(4) of the 1998 Act, declined to assess the degree of the appellant’s permanent impairment. Medical Assessor Glozier said in the MAC he issued that the degree of permanent impairment of the appellant could be evaluated six months after the instigation of a different antidepressant to the one the appellant had been taking for over a decade.
On 21 April 2023 a delegate of the President of the Personal Injury Commission (Commission) issued an amended referral to Medical Assessor Smith requiring the Medical Assessor to assess various medical disputes between the parties including the degree of the appellant’s permanent impairment from her injury, whether her degree of permanent impairment is fully ascertainable and whether any proportion of her permanent impairment is due to any previous injury or pre-existing injury or abnormality and the extent of that proportion.

THE MEDICAL ASSESSMENT CERTIFICATE

Medical Assessor Smith examined the appellant on 2 May 2023. He assessed the degree of her permanent impairment was 19% WPI. Neither party has raised any issue with that. The appellant’s appeal relates to the deduction the Medical Assessor made under s 323(1) of the 1998 Act for the proportion of the appellant’s impairment that the Medical Assessor considered was due to a pre-existing condition. Medical Assessor Smith assessed that proportion was 50% and he deducted that from the 19% WPI he assessed the appellant had, such that he certified in the MAC he issued on 23 May 2023 that the degree of the appellant’s permanent impairment from her injury was 10% WPI.
Medical Assessor Smith provided the following “summary of injuries and diagnoses” in part 7 of the MAC:
“Ms Diemar is a 61-year-old woman previously employed as a dental therapist. Her mental health deteriorated after she became involved in what she characterised as an abusive and intimate relationship with her employer over several years. The interpersonal dynamics surrounding the injury were complex, and various parties provided differing accounts. Numerous clinicians and independent examiners have characterised her presentation as complex, and diagnoses have included bipolar disorder, borderline personality disorder, anxiety, depression, tic disorder, attention deficit hyperactivity disorder, post-traumatic stress disorder, and obsessive-compulsive disorder. She has a history of periods of significant psychiatric instability pre-dating the injury, including admission to a public psychiatric hospital. She was on treatment for depression and anxiety before her employment with the Respondent. She was involved in a traumatic motor vehicle accident fatality and discussed symptoms of PTSD with several clinicians attributed to the accident. She has a strong family history of psychiatric disorders, particularly suicide and OCD spectrum disorders and developmental vulnerabilities, including developmental trauma.
In my view she developed a major depressive disorder on a background of pre-existing
borderline personality disorder and recurrent major depressive disorder. There was
insufficient information to be certain about a diagnosis of bipolar disorder. She has
confirmed pre-existing OCD spectrum symptoms, including tics, a history of ordering
compulsions and possibly attention deficit disorder. I agree with Professor Glozier that there was no apparent trauma meeting criterion A for PTSD in the course of her employment. The features meeting the DSM-V criteria for a major depressive disorder include persistently depressed mood, loss of interest in previously enjoyed activities, fatigue, impaired concentration, depressive thoughts and sleep disturbance. The current episode is an aggravation of a longstanding recurrent major depressive disorder.
The features meeting DSM-V criteria for borderline personality disorder include a pervasive pattern of instability of interpersonal relationships, self-image and affects with marked impulsivity beginning by early adulthood and present in a variety of contexts as indicated by a pattern of unstable and intense interpersonal relationships, identity disturbance, markedly and persistently unstable self-image or sense of self, impulsivity in at least two areas that are potentially self-damaging such as substance use or risky sexual behaviour, affective instability due to marked reactivity of mood; for example, intense episodic dysphoria, irritability or anxiety usually lasting a few hours and only rarely more than a few days, inappropriate, intense anger or difficulty controlling anger and transient stress-related paranoid thoughts or severe dissociative symptoms. I agree with Dr Raggatt that the symptoms of borderline personality disorder have attenuated over time, consistent with the natural history of borderline personality disorder.
Both borderline personality disorder and recurrent major depressive disorder are preexisting conditions that substantially affect the work-related injury. Apportionment for the effects of pre-existing conditions is discussed below.”
The Appeal Panel observes that Dr Raggatt is a consultant psychiatrist to whom the appellant’s general practitioner (GP) referred the appellant for treatment. Dr Raggatt saw the appellant twice, firstly on 14 June 2016 and then in December 2019.
Medical Assessor Smith recorded within the history he set out in the MAC that the appellant’s past psychiatric history included a tic disorder, ordering compulsions and attention deficit hyper-activity disorder from childhood. He recorded that the appellant reported not experiencing any mental health treatment before being involved in a motor vehicle accident in June 1998 in which she struck a cyclist who was pregnant and resulted in the cyclist losing her unborn child. Medical Assessor Smith recorded that the psychiatrist whom the appellant then consulted, namely Dr Newnham, recorded in his clinical records that the appellant had recurrent flashbacks and dreams in 2011. Medical Assessor Smith also recorded that the appellant requested to be referred to a psychologist in 2018 to manage post-traumatic stress disorder attributed to the accident.
Medical Assessor Smith recorded in the history he obtained that Dr Newnham had also noted in 2011 that the appellant had symptoms of hypomania that the appellant attributed to attention deficit disorder and that the appellant did not accept a diagnosis of bipolar disorder.
Medical Assessor Smith recorded that the appellant’s brother committed suicide in 2006 and that her nephew committed suicide three years later in 2009. Medical Assessor Smith recorded that the appellant was admitted to James Fletcher Hospital in January 2010 after she had become overwhelmed and broke down with grief and was crying and screaming, following having lunch that day with her mother and a night out with friends when she had been discussing the suicides. Medical Assessor Smith noted that the admission to James Fletcher Hospital was for three weeks and the appellant was diagnosed with bipolar disorder and discharged on sodium valproate and quetiapine at doses suggesting bipolar disorder.
Medical Assessor Smith recorded that the medical records relating to the appellant showed a history of escitalopram use up to 20mg pre-dating the appellant’s injury and sertraline and hypnotic scripts from 2001.
Medical Assessor Smith detailed within part 10c of the MAC relevant parts from the clinical records and medical reports that were before him relating to the appellant’s past psychiatric history. These included notes recorded by the general practitioners (GP) the appellant consulted at the Nelson Bay Medical Group.
Medical Assessor Smith noted that the appellant’s GP recorded on 26 February 2001 that the appellant was prescribed sertraline 50mg and a script for zolpidem 10mg and a script for temazepam on 18 June 2001.
The Medical Assessor noted that on 2 November 2006 the GP whom the appellant consulted recorded the appellant had serious anxiety-depression from her brother’s death. The Medical Assessor observed a note dated 23 November 2006 recording that the appellant was “embarrassed, emotional, crying, lots of trouble with the kids, and not sleeping”. The Medical Assessor noted that the appellant’s GP increased the appellant’s dose of sertraline to 100mg with an additional script for zolpidem and diazepam. The Medical Assessor noted that on 9 January 2007 sertraline was recorded as being effective and that it was tapered to 50mg on 7 March 2007. Medical Assessor Smith noted that the GP recorded on 22 April 2008 that the appellant presented for assessment of anxiety and that on 30 September 2008 the GP discussed panic disorder with the appellant. Medical Assessor Smith noted that the GP on 13 October 2009 recorded the appellant presented with depression and noted the recent suicide of the appellant’s nephew and a strong family history of depression. Medical Assessor Smith noted that the GP referred the appellant to a psychologist. Medical Assessor Smith noted that the GP recorded on 5 February 2010 the appellant presented with reactive depression, following her discharge from James Fletcher Hospital. Medical Assessor Smith noted that the GP recorded on 1 October 2010 that the appellant presented pressured speech and needed to start medication suggestive of a manic or hypomanic state. The Medical Assessor noted the appellant’s GP recorded on 18 February 2011 the appellant was feeling foggy with tegretol and queried the possibility of bipolarity. The Medical Assessor noted the appellant’s GP recorded on 16 May 2011 that the appellant had bipolar with personality traits. The Medical Assessor noted that a referral was made to
Dr Newnham. Medical Assessor Smith noted that the appellant’s GP on 27 July 2011 noted the appellant had suicidal thought.
Medical Assessor Smith noted that Dr Newnham initially assessed the appellant on
1 June 2011 and described the appellant had a hypomanic with a complex family history and diagnostic uncertainty. Medical Assessor Smith noted that the appellant had detailed to
Dr Newnham a family history of developmental trauma and that she had been married to an emotionally abusive man from whom she divorced in 2001. Medical Assessor Smith noted that Dr Newnham recorded that the appellant’s divorce came shortly after the appellant was involved in a motor vehicle collision involving a cyclist who lost an unborn child. Medical Assessor Smith noted that Dr Newnham recorded that the appellant had recurrent flashbacks and dreams about that incident 10 years after it. Medical Assessor Smith noted that
Dr Newnham recorded the appellant had periods of serious depression and fluctuating suicidal ideations throughout her life and that she was admitted to James Fletcher Hospital in 2009 with unclear circumstances and was discharged on sodium valproate and m.
Medical Assessor Smith also noted within part 10c of the MAC that Dr Davies had made a diagnosis of post-traumatic stress disorder. Medical Assessor Smith considered that the appellant’s work related injury did not meet the diagnostic criteria for post-traumatic stress disorder. Medical Assessor Smith also recorded that Medical Assessor Glozier had said in the MAC he issued on 16 April 2021 that the events that the appellant suffered in her workplace did not constitute criterion A for a diagnosis of post-traumatic stress disorder to be made and that the appellant did not have re-experiencing phenomena but rather a depressed and somewhat obsessive rumination about the events that were concordant with a recurrent depressive disorder.
At part 11a of the MAC Medical Assessor Smith expressed his opinion that the appellant’s pre-existing conditions were recurrent major depressive disorder and borderline personality disorder. He explained in the following terms why he had assessed the proportion of the appellant’s permanent impairment due to those pre-existing conditions was 50%:
“b. The previous injury, pre-existing condition or abnormality directly contributes to the following matters that were taken into account when assessing the whole person impairment that results from the injury, being the matters taken into account in 10a, and in the following ways:
(i) The history and documentation confirm a history of recurrent major depressive disorder and borderline personality disorder pre-dating the injury impacting her function at work and the nature of her relationship with her employer. In determining the burden of impairment apportioned to pre-existing conditions, I considered Ms Diemar’s self-reported history, the documentation provided, the documented collateral history from her treating clinicians, the natural history of these disorders and reports
from multiple independent medical examiners.
(ii) Both borderline personality disorder and recurrent major depressive disorder are pre-existing conditions that substantially impact the work-related injury. They are independent risk factors for recurrent depressive episodes, particularly in the context of interpersonal stressors and perpetuate the depressive episode.
c. Whilst the extent of the deduction is difficult or costly to determine the available evidence is that the deductible proportion is large and a deduction of one tenth is at odds with the available evidence. In my opinion the deductible proportion is 50%for the following reasons:
(i) The current impairment is a product of her existing psychological disorders and the effects of the subject injury. Ms Diemar’s pre-event psychological status was fragile and impacted her work function and relationships. The index event worsened a preexisting clinical-level psychological disorder.
(ii) There is ongoing rumination, preoccupation and aversion to reminders of her employer, confirming an ongoing work-related component to her mood disorder and aggravation of borderline personality disorder. However, I cannot conclude that the larger portion of her psychological impairment arises from a work-related psychological injury. The pre-existing condition and the work-related injury have substantial impacts; one is not greater than the other.”

PRELIMINARY REVIEW

The Appeal Panel conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Procedural Direction PIC7.
As a result of that preliminary review, the Appeal Panel determined that it was not necessary for the appellant to undergo a further medical examination. This is for two reasons. Firstly, the Appeal Panel, for reasons explained below, found that none of the grounds for appeal on which the appellant relied was established. Consequently, the Appeal Panel confirmed the MAC and did not need to re-assess the medical dispute that had been referred for assessment. Secondly, absent the Appeal Panel finding error in the MAC, the Appeal Panel does not have power to examine the appellant.[1]
[1] NSW Police Force v Registrar of the Workers Compensation Commission of NSW [2013] NSWSC 1792 at [33]; Ziraki v The Australian Islamic Liverpool Area [2019] NSWSC 1158 at [74]; Coenradi v the GEO Group Australia Pty Ltd [2002] NSWSC 864 at [134]; and Finnegan v Komatsu Forklift Australia Pty Ltd [2023] NSWSC 38 at [125]-[130].
The Appeal Panel also considered during its preliminary review an application of the appellant that the Appeal Panel receive into evidence a statement the appellant made on
7 June 2023. In that statement the appellant recounted what she said the Medical Assessor had said to her at the conclusion of the assessment which was “and you must feel an immense amount of guilt and shame with having the affair”. The appellant said in her statement that she believed she nodded her agreement.
Section 328(3) of the 1998 Act provides that evidence that is fresh evidence or evidence in additional to or in substitution for the evidence received in relation to a medical assessment appealed against may not be given on an appeal by a party unless the evidence was not available to the party before the medical assessment and could not reasonably have been obtained by the party before that medical assessment.
The Appeal Panel considers that the further statement of the appellant lacks probative value and will not affect the result of the Appeal Panel’s determination of the appeal. The Appeal Panel’s determination of whether the MAC contains a demonstrable error or whether the Medical Assessor based his assessment on incorrect criteria will be determined from what appears on the face of the MAC, that is from the Medical Assessor’s explanation for his assessment contained within the MAC and the documents that were provided to him for the assessment. That is done by an objective consideration of the MAC, read as a whole, and the material that was provided to the Medical Assessor for his assessment. The Medical Assessor’s reasons as articulated in the MAC are what is relevant. His subjective thoughts regarding how the appellant felt cannot be known and are not germane.
Whilst the evidence the appellant seek the Appeal Panel receive is fresh evidence in the sense that it was created after the Medical Assessor’s assessment, the Appeal Panel still has a discretion regarding whether to accept it into evidence. The evidence will not establish any of the grounds for appeal upon which the appellant relied. Given that, the Appeal Panel has exercised its discretion to refuse to accept it into evidence.[2]
[2] Lukacevic v Coates Hire Operations Pty Ltd [2011] NSWCA 112 at [40] and [78].
The Appeal Panel also considers that the appellant’s further statement does not contain any additional relevant information such as to establish the ground for appeal listed in sub-section 327(3) of the 1998 Act as it does not contain information relating to her psychiatric illness or her function upon her psychiatric illness. It is not information of a medical kind or which relates to the assessment the Medical Assessor made.[3]
[3] Petrovic v BC Serve no: 14 Pty Ltd [2007] NSWSC 1156 at [31].

EVIDENCE

The Appeal Panel has before it all the documents that were sent to the Medical Assessor for the original medical assessment and has taken them into account in making this determination.

SUBMISSIONS

Both parties made written submissions. They are not repeated in full, but are paraphrased by the Appeal Panel immediately below by way of providing a summary.
In summary, the appellant submitted that the Medical Assessor made his assessment of her permanent impairment based on incorrect criteria because he did not apply clause 11.10 of the Guidelines. The appellant referred to Marks v Secretary, Department of Communities and Justice (no. 2) [2021] NSWSC 616 (Marks) as authority for that.
The appellant submitted that the Medical Assessor, having found that it would be difficult and costly to determine the deductible proportion to be made under s 323(1) of the 1998 Act, erred by making a deduction exceeding 10% for the proportion of her permanent impairment due to a pre-existing condition. The appellant submitted difficulty of determining what the deductible proportion should be is reinforced by the fact that the clinicians who treated her had different opinions regarding the diagnosis of her pre-existing condition.
The appellant submitted that the Medical Assessor erred by excluding a diagnosis of post-traumatic stress disorder on the basis she did not meet criterion A for such a diagnosis to be made. The appellant submitted that the Medical Assessor’s finding that criterion A was not met was based on his failure to recognise the severity of the abuse to which she was subjected by Dr Park and by incorrectly categorising her relationship with Dr Park as “a consensual office affair”. The appellant submitted that the Medical Assessor characterised her relationship with Dr Park “as more of a consensual affair than a seriously abusive relationship” and that this allowed “him to diminish the effects of that trauma and to attribute less weight to it in his WPI assessment”.
The appellant submitted that the trauma that she suffered in her workplace that resulted in her suffering her work injury “stands alone from any pre-existing condition” and that a greater proportion of her WPI should be attributed to that than her pre-existing condition.
The appellant submitted that the Medical Assessor erred by failing to take account of her progress since her hospitalisation in 2010 with respect to her educational achievements and her career achievements.
In reply, the respondent submitted that in Marks it was held that clause 11.10 of the Guidelines is invalid to the extent to which the clause is inconsistent with s 323.
The respondent submitted that the Medical Assessor acknowledged the complexity of the appellant’s medical condition was such that to assume pursuant to s 323(2) of the 1998 Act that the deductible proportion for the purpose of s 323(1) of the 1998 Act was 10% was at odds with the evidence. The respondent submitted that it was open to the Medical Assessor to reach that conclusion and that the Medical Assessor set out his path of reasoning for that conclusion.
The respondent submitted that based on a fair reading of the MAC it could not be said that the Medical Assessor underestimated the impact of the appellant’s relationship with her employer.

FINDINGS AND REASONS

The procedures on appeal are contained in s 328 of the 1998 Act. The appeal is to be by way of review of the original medical assessment but the review is limited to the grounds of appeal on which the appeal is made.
In Campbelltown City Council v Vegan [2006] NSWCA 284 the Court of Appeal held that the Appeal Panel is obliged to give reasons.
The Appeal Panel does not accept the appellant’s submission that the Medical Assessor mischaracterised the relationship between her and Mr Park as being a “consensual office affair” or being “more of a consensual affair than a seriously abusive relationship”. The Medical Assessor recorded in the MAC that the appellant considered the relationship was akin to a controlling domestic violence relationship and that she considered her relationship with Mr Park as abusive. The Medical Assessor said in the MAC that in making his assessment he took into account, amongst other things, the history that the appellant provided him, which included how she characterised her relationship with Mr Park. The Appeal Panel considers that when the MAC is read as a whole it is apparent that the Medical Assessor accepted that the trauma that the appellant experienced in her workplace, that resulted in her injury, included the relationship between her and Mr Park and the effect that relationship had on her.
The Appeal Panel also considers that it was open to the Medical Assessor to diagnose the appellant as having recurrent major depressive disorder. For the reasons the Medical Assessor provided, the appellant’s presentation met the criteria specified within DSM-5 for that illness. The Medical Assessor identified the features of that illness that the appellant had were persistently depressed mood, loss of interest in previously enjoyed activities, fatigue, impaired concentration, depressive thoughts and sleep disturbance.
It is also clear that the appellant’s work experience does not fulfil the mandatory post-traumatic stress disorder’s Criterion A, “exposure to actual or threatened death, serious injury, or sexual violence.” It was appropriate for the medical assessor to exclude this diagnosis.
Clauses 11.4 and 11.6 of the Guidelines require a Medical Assessor to make a diagnosis of a worker’s injury. Consistent with that, it was necessary for the Medical Assessor to make a diagnosis of the appellant’s work injury, and the Appeal Panel considers it was open to the Medical Assessor to diagnose the appellant’s injury as an aggravation of a long standing recurrent major depressive disorder on a background of a borderline personality disorder. That some psychiatrists arrived at different diagnoses does not demonstrate error on the part of the medical assessor. In part, this may be due to a misapplication of the diagnostic criteria by previous assessors, as with ignoring Criterion A for post-traumatic stress disorder or, at times, merely an expression of opinion on which reasonable minds may differ.
In any event, whether the Medical Assessor could have made a different diagnosis of the appellant’s illness and injury did not affect his assessment of the appellant’s permanent impairment and this is because he assessed the appellant’s impairment by reference to the effect the appellant’s psychiatric injury had on her functioning. It is the role of the medical assessor to determine the diagnosis or diagnoses and then assess the impairment that results. These are different things and the impairment level is not a direct function of the diagnosis.
As mentioned, there is no issue taken with respect to the Medical Assessor’s assessment of the appellant’s overall permanent impairment resulting from her injury. What is in issue is whether the Medical Assessor was wrong not to engage s 323(2) of the 1998 Act to assume that the proportion of her permanent impairment that was due to her pre-existing was 10%.
A proportion of permanent impairment will be due to a pre-existing condition if the condition makes a difference to the outcome for a worker in terms of the degree of permanent impairment resulting from a work injury.[4] Hence, to the extent that the pre-existing condition makes a difference to the outcome there must be a deduction. A Medical Assessor’s assessment of the extent to which a worker’s permanent impairment resulting from a work injury is due to a pre-existing condition is a matter for medical assessment based on the evidence before the Medical Assessor.[5]
[4] Ryder v Sundance Bakehouse [2015] NSWSC 526 at [45].
[5] Drosd v Workers Compensation Nominal Insurer [2016] NSWSC 1053 at [74]-[86].
In this matter the Medical Assessor set out in the MAC the appellant’s extensive history of psychiatric illness that preceded her workplace injury. That revealed the appellant had an extensive psycho-pathology preceding commencement of her employment with the respondent. The appellant functioned well subsequent to her hospitalisation and had completed tertiary education to qualify for a Bachelor of Oral Health and a Graduate Diploma of Dental Hygiene with honours. The appellant also initially functioned well in her work setting nevertheless the evidence indicates that despite functioning well in the period preceding her workplace injury she had long standing symptomatic psychiatric illness. That illness had resulted in her hospitalisation not long before she commenced her employment with the respondent, following discussions she had with friends and with her mother regarding the suicide of her brother and nephew. It had resulted in the appellant experiencing recurrent flashbacks and dreams more than a decade after a motor accident incident in June 1998 in which a cyclist lost her unborn child and a hospitalisation in January 2010.
The appellant does not dispute that a deduction was to be made under s 323(1) of the 1998 Act, but rather the Medical Assessor was wrong not to assume in accordance with s 323(2) of the 1998 Act that the deducted proportion was to be 10%.
Section 323(2) of the 1998 Act reads as follows:
“If the extent of a deduction under this section (or a part of it) will be difficult or costly to determine (because, for example, of the absence of medical evidence), it is to be assumed (for the purpose of avoiding disputation) that the deduction (or the relevant part of it) is 10% of the impairment, unless this assumption is at odds with the available evidence.”
Hence, in a circumstance where the evidence indicates that making such an assumption is wrong then a Medical Assessor cannot make the assumption and must assess the matter as best he or she can with the available evidence.
The Medical Assessor’s reasons for concluding that the proportion of the appellant’s permanent impairment from her injury was due to her pre-existing conditions were, in substance, that:
(a)    the appellant’s impairment is both the product of her work injury and her prior psychiatric illnesses of recurrent major depressive disorder and borderline personality disorder;
(b)    the appellant’s work injury “worsened a pre-existing clinical level psychological disorder”;
(c)    both the appellant’s pre-existing condition and her work injury had substantial impacts and that one is not greater than the other; and
(d)    he could not conclude that a larger proportion of the appellant’s impairment results from her injury than her pre-existing conditions.
Those reasons of the Medical Assessor, in the Appeal Panel’s view, amount to his finding that making an assumption that the proportion of the appellant’s permanent impairment due to her pre-existing conditions is 10% would be at odds with the evidence that was before him. In other words, s 323(2) could not be engaged to determine the deduction to be made under s 323(1).
The Medical Assessor set out in the MAC the circumstances the appellant encountered in her workplace that gave rise to her workplace injury. It is apparent from the MAC that the Medical Assessor was cognisant of the trauma that had caused the appellant injury. The Medical Assessor also set out in the MAC the evidence that he considered was at odds with assuming that the deduction to be made under s 323(1) is 10%. That evidence was the history he obtained regarding the appellant’s prior psychiatric illness and relevant parts of the clinical material recording the appellant’s past presentations to her treating clinicians. When the MAC is considered as a whole, the Appeal Panel considers that the Medical Assessor provided adequate reasons for concluding why that evidence was at odds with making an assumption that the deductible proportion should be 10%. When the MAC is considered as a whole it is apparent why the Medical Assessor formed that view, and the Appeal Panel, which is an expert panel, agrees with it.
The Medical Assessor’s conclusion was basically that but for the appellant’s pre-existing psychiatric conditions her permanent impairment from the injury she suffered due to the traumatic events to which she was subjected in her workplace would have only been half of what her permanent impairment presently is. Given the extensive psycho-pathology the appellant had preceding her workplace injury, the Appeal Panel considers that there is no error in the exercise of the Medical Assessor’s judgment, based on the evidence before him, in reaching that conclusion.
The Appeal Panel also does not accept the appellant’s submission that the Medical Assessor was required by clause 11.10 of the Guidelines to assess her permanent impairment based on the evidence of her pre-injury functioning and then deduct that from the impairment he assessed her to have post-injury. The Appeal Panel does not accept that Marks supports that contention. Simpson AJ in Marks held that clause 11.10 of the Guidelines conflicted with s323(1) of the 1998 Act insofar as it required no deduction to be made under s 323(1) in cases where an asymptomatic pre-existing condition contributed to the degree of permanent impairment assessed. Her Honour held that clause 11.10 was invalid to the extent that it did so.
In this case the appellant’s pre-existing condition was not asymptomatic and hence Marks is not strictly binding. However, irrespective of whether a pre-existing condition is symptomatic or asymptomatic, what is required when applying s 323(1) is an assessment of the extent to which a pre-existing condition contributes to a worker’s current impairment, that is at the time the assessment is done. Marks supports that. Whether her pre-existing condition could be assessed based upon the psychiatric impairment rating scale prior to the occurrence of her injury, is irrelevant to that task.[6]
[6] Secretary, Department of Communities & Justice v Lewandowski [2023] NSWSC 334.
The evidence in this case is not sufficient, in any event, to enable a reliable assessment to be done of the appellant’s impairment before the occurrence of her injury and any assessment done under the psychiatric impairment rating scale, based on what evidence there was before the Medical Assessor of the appellant’s function before injury, would likely result in no deduction being made, which is contrary to s 323(1) of the 1998 Act. That is to say, to apply clause 11.10 in this case would be contrary to what is required under s 323(1) of the 1998 Act. What is required under that provision is an assessment of what the current proportion of the appellant’s permanent impairment is due to her pre-existing condition.
For these reasons, the Appeal Panel has determined that the MAC issued on 23 May 2023 should be confirmed.

[2023] NSWPICMP 423

30 August 2023