New South Wales Supreme Court CITATION : R v Worrall [2010] NSWSC 593 HEARING DATE(S) : 26 March 2010 JUDGMENT DATE : 4 June 2010 JUDGMENT OF : Fullerton J DECISION : I sentence you to imprisonment for a non-parole period of 4 years and 3 months commencing on 10 October 2008 and expiring on 9 January 2013 and a balance of term of 1 year and 9 months expiring on 9 October 2014. CATCHWORDS : CRIMINAL LAW - sentence - manslaughter - abnormality of mind - congenital adrenal hyperplasia - non-compliance with medication LEGISLATION CITED : Crimes Act 1900 Crimes (Sentencing Procedure) Act 1999 CATEGORY : Sentence CASES CITED : YS v R [2010] NSWCCA 98 PARTIES : The Crown Kathleen Worrall (Offender) FILE NUMBER(S) : SC 2009/8784 COUNSEL : P Barrett (Crown) J Stratton SC (Offender) SOLICITORS : Director of Public Prosecutions (Crown) Legal Aid Commission (Offender) IN THE SUPREME COURT OF NEW SOUTH WALES COMMON LAW DIVISION FULLERTON J 4 JUNE 2010 2009/8784 R v KATHLEEN WORRALL JUDGMENT 1 HER HONOUR: On 4 December 2009 the Crown presented an indictment charging the offender, Kathleen Worrall, with the murder of her sister Susan Worrall. Her sister died on the morning of 10 October 2008 within a short time of suffering multiple stab wounds to her neck and back in their family home at Strathfield. 2 On arraignment the offender pleaded guilty to manslaughter on the basis that her liability for the murder of her sister was reduced by reason of an abnormality of mind, namely a mood disorder associated with her non-compliance with medication prescribed for the treatment of her underlying medical condition, namely congenital adrenal hyperplasia, as provided for in s 23A of the Crimes (Sentencing Procedure) Act 1999 ("the Sentencing Act"). The Crown accepted the offender's plea of guilty in full satisfaction of the indictment. The offender has been in custody since the date of the offence. Evidence tendered on sentence 3 The evidence tendered by the Crown included an agreed statement of facts, a transcript of an interview between police and the offender conducted on 31 October 2008, and statements of the police who initially attended the scene and spoke with the offender. The Crown also tendered psychiatric reports from Dr Stephen Allnutt dated 18 May 2009 and Dr Yvonne Skinner dated 27 August 2009. 4 The offender tendered psychiatric reports from Dr Olav Nielssen dated 21 January 2009 and 26 February 2010, and Dr Bruce Westmore dated 6 July 2009, together with reports from her treating endocrinologists, Professor Martin Silink and Dr Deborah Jane Holmes-Walker. She also tendered a large number of personal references. I received into evidence a letter from the offender dated 20 March 2010 and a letter on behalf of the Worrall family tendered as a victim impact statement. 5 The offender did not give evidence. Dr Nielssen and Mrs Worrall gave evidence, in Mrs Worrall's case in her capacity as the mother of the deceased and the offender. The offender's relationship with her sister preceding her death 6 The offender was aged 20 at the time of the offence. The deceased was aged 18. The offender and the deceased were the only children of John and Maureen Worrall. Both the offender and the deceased lived with their parents in the family home at Strathfield. At the time of the offence the offender was undertaking a Bachelor of Arts degree at the Australian Catholic University. The deceased was in her final year of high school at the Methodist Ladies College at Burwood. 7 On 5 October 2008, five days before she fatally stabbed her sister, the offender sent a text message to a close friend and confidante stating that she was going to kill her sister that night unless she was persuaded otherwise. She apparently said that "desperate times call for desperate measures" and that she hoped her friend would understand. Her friend dissuaded the offender from harming her sister and urged her to tell her parents. The offender then sent a further text message to her friend that night in which she stated that she was feeling homicidal. 8 Her friend did not bring the offender's apparently unsettled emotional state to the attention of her parents, or take any steps herself to monitor the offender's mood or behaviour over subsequent days. This is likely explained by the complexities inherent in their relationship consequent upon the offender developing an unrequited infatuation with her friend over the course of the previous year. This is supported by the offender's diary entries that were considered by Dr Allnutt in the course of preparing his report. While the infatuation may not have diminished their friendship at a platonic level, I suspect it resulted in her friend maintaining an emotional distance and disengagement from the offender such that she may not have taken the offender's threats seriously. 9 In the course of the same week the deceased and the offender had an argument about a hair straightening appliance that ended in a physical fight in which they pulled each other's hair and exchanged punches. Following the fight the offender claimed the deceased threatened her verbally, boasting that their parents would support her if the offender were killed. She also told Dr Skinner that she countered with threats of her own. Although Mr Worrall intervened and confiscated the hair straightener, there is nothing to support either of the offender's parents being aware of the threats that issued thereafter. 10 In a telephone conversation with Mr Worrall on 29 April 2009 Dr Allnutt, a forensic psychiatrist retained by the Crown, reported that he could not understand or explain how one of his daughters came to fatally stab the other. After making due allowance for his understandable, even if unconscious, desire to reconstruct the days or weeks leading up to the killing so as to enable him to accept the death of one daughter and the criminal liability of the other daughter for that death, his insights into the relationship between his daughters are helpful. He told Dr Allnutt that despite the predictable range of disagreements that erupted in the household from time to time, his daughters being young women in their formative adolescent years living in a close family setting, the offender was loving and supportive of her sister. He also said that the offender's age and her relative emotional maturity (perhaps a reflection of her complex medical history) operated as a stabilising influence. He said the deceased, by comparison, was sometimes cruel and vindictive in the heat of family or sibling conflict (on occasions prompting the offender to tell her to leave the house) after which she would quickly relent and apologise. On reflection Mr Worrall simply regarded these outbursts as an ordinary incident of family life in a domestic environment dominated by two daughters, close in age, who were growing in self-awareness and independence. He did emphasise, however, that the offender's underlying condition, and in particular her weight, affected her self-esteem, making her an obvious target for attack by her sister and vulnerable to hurt. 11 In the letter tendered in the proceedings the offender described her relationship with the deceased as "two halves of a whole … with a shared understanding of one another that can only come from being close sisters". No longer labouring under the impairment which reduces her culpability for the death of her sister from murder to manslaughter, I accept that this is an accurate reflection of the way the offender now sees her relationship with the deceased despite the fact that whilst still in a manic phase of her illness she told Dr Nielssen that she killed her sister at the climax of a bad relationship and that she had felt sustained animosity towards her sister for some years. I also accept her letter as reflecting her essential love for her sister and her deep and lasting remorse at having killed her. The day of the offence 12 At 8am on 10 October 2008 the offender was woken by her mother before she left for work. The deceased remained asleep in her own bedroom. Mr Worrall was at the family holiday house in Moss Vale undertaking regular weekly maintenance. 13 Upon rising the offender armed herself with three knives. She told Dr Nielssen she purchased a knife some days earlier from K-Mart specifically for the purpose of using it to stab the deceased. She told Dr Allnutt that she purchased the knife to harm herself. Having regard to the degree of planning the offender actively engaged in preparation for killing her sister, I am satisfied she purchased the knife as part of those preparations. She took the other two knives from the kitchen. With one knife in her hand and two tucked in her bathrobe belt, she approached the deceased while she was still asleep in her bedroom with the intention of stabbing her. She claims to have changed her mind, leaving the deceased's room without waking her. She said she put the knives away. 14 A short time later however an argument erupted between the offender and her sister in the kitchen about the evening meal. The deceased left the kitchen and went into the bathroom to have a bath. The offender again armed herself with three knives and approached the bathroom door with the intention of stabbing the deceased. She again decided against it. She then decided to use the computer but was unable to log on to the internet because the deceased had changed the password. 15 The offender stood outside the closed bathroom door and said to the deceased "If I can't have the internet, neither can you". She was armed with the three knives at this time. When the deceased came out of the bathroom the offender grabbed her around the neck and stabbed her repeatedly in the neck and back. 16 The offender then called her father at Moss Vale and told him that she had stabbed her sister and that she had blood all over her. Mr Worrall told the offender to call 000 and to tell them that she had stabbed her sister and to request the attendance of ambulance and police. The offender telephoned 000 and said to the operator "I killed my sister, I think I stabbed her". The offender told the operator that the deceased was lying in the hallway and that she was not conscious or breathing. She said that there was a lot of blood and that she had put a towel on the deceased. The operator asked the offender to check the deceased's breathing. The offender said "God no, I don't want to touch her … her neck is cut … open". The offender then told the operator that she had put the knives she used to stab the deceased in the sink. 17 At 11.35am police attended the family home. The offender answered the front door. She appeared dishevelled and distressed. Her bathrobe was covered with a significant amount of blood. There was also blood on her legs up to her knees, her feet, her arms and her face. Police escorted the offender from the house and entered the premises. 18 Police found the deceased lying naked, face down in the hallway of the house with a white towel placed on top of her body. They noted open wounds to her back and neck. 19 Police cautioned the offender outside the premises and asked her if there was a knife. The offender told police that the knives she used to stab the deceased were in the kitchen sink. Police located the knives, which were left in situ, until seized by specialist forensic police a short time later. The offender was then arrested and re-cautioned before being conveyed to Burwood Police Station. 20 Ambulance officers attended the scene and briefly examined the deceased. Due to the nature of the wounds, including a large laceration to the neck which severed major arteries, they determined that there was no prospect of the deceased being successfully resuscitated. 21 After being conveyed to Burwood Police Station, the offender requested the attendance of her close friend and confidante. She was permitted to speak with the offender. She asked the offender "What have you done? You know Susan is dead don't you?", to which the offender responded "I know, I don't care. I am glad the bitch is dead". When asked by her friend what they had fought about, the offender replied: "The hair straightener. I've just had enough". 22 The offender agreed to participate in an electronically recorded interview. Despite confirming that she placed the knives in the kitchen sink and that no one else had been in the house that morning, she refused to answer direct questions regarding the offence, including questions about the fight with the deceased, how it was that she came to be fatally wounded on the floor in the hallway or in what order the knife wounds were inflicted. She was remanded in custody. 23 Following her arrest, and two days after being taken into custody, the offender told two Corrective Services Officers that she had planned to kill her sister when she knew both of her parents would be out of the house. She also told the officers that prior to committing the offence she had been angry with the deceased for preventing her internet access by changing the password. She said that she had purchased one knife four or five days earlier from K-Mart and that she had obtained the other two from the kitchen. She also told the officers what she later told Dr Neilssen, namely that she approached the deceased on two prior occasions earlier in the morning but did not carry through her intentions to stab her sister at that time but that as the deceased opened the bathroom door to leave the bathroom she grabbed her sister around the neck and stabbed her in the throat numerous times before she fell face down on the floor. The offender then said that she stood over the deceased and could hear her gasping for air and that the gasping would subside then resume. She said that she thought her sister was faking it and not really dead, and that she yelled at her saying "You're faking it. Stop faking it". Then she said she stabbed her again. She said that was when she realised her sister was dead "because her eyes were just (staring) in front". What the offender told Dr Nielssen in November 2008 24 When asked about the events leading up to the offence by Dr Nielssen in November 2008, the offender told Dr Nielssen about the fight with her sister over the hair straightener. She said that although she and her sister played when they were younger, there was a personality clash as teenagers. She said that in the week after the fight the deceased had started saying things to her like "You won't be so strong with a knife in your back" and "Sleep with one eye open" and "I could murder you … mum and dad would stick up for me". She said she believed her sister would carry out her threats and that she was scared of her. 25 The offender confirmed that she had researched the internet for information about knife wounds from which she concluded that she should sever the carotid artery as she wanted her sister's death to be quick. She said that she did not want to hurt her, she just wanted her to disappear. She confirmed what she had told the Corrective Services officers, namely that she had bought a knife from K-Mart four or five days prior to the offence. She also said that in preparation for the killing she had taken two other knives from the kitchen because her internet research indicated that more than one knife may be necessary. 26 When asked about the day of the offence, the offender revealed that after her mother had left for work she had disconnected the phone because she knew her mother would call to wake her sister. She told Dr Nielssen that although she had armed herself with the three knives with the intention of killing the deceased she was twice overcome with anxiety. Of the first attempt, she explained that she saw her sister asleep with her neck exposed and that her body started shaking, she felt a knot in her stomach and she could not carry through her intentions. 27 The offender went on to say: "I took three knives because I knew it would get slippery and I needed backups … it had to be all or nothing … I'm ashamed to say it … I went into her room as she was getting out of the bath … or maybe she came out of her room … here it gets blurry … it went black and then I get a shot of reality and then it goes black again … I remember this detail that I was thinking of a kind of karate in which the best defence is offence with rapid movement and I thought go, go, go". 28 The offender remembered the deceased saying "No Kathleen, I love you, I love you, please stop", but at the same time she was conscious that her sister had never said she loved her, and that she thought she was just saying these things to try to stop her. She said she grabbed her sister's neck with her left hand and stabbed her with her right hand. She said it took no more than 30 seconds. She said that her memory faded until she saw her sister hit the floor. 29 When asked about what outcome she expected when she ultimately resolved to stab the deceased, the offender said: "I'm not sure … but part of me wanted her to disappear … the bigger part was wanting a happy family again … I love my parents … they didn't deserve the way she treated them … I never thought killing her was right or what would happen to me … I just wanted her gone". 30 When asked whether at the time of the offence she believed she was in any danger from her sister, the offender said: "I never really knew for sure but my instincts said yes … anyway she was going to make my life a living hell … she turned the family against me … turning off the internet was the last straw". 31 The offender denied committing the offence because of feelings of jealousy towards her sister. What the offender told Dr Allnutt in May 2009 32 After a follow-up interview with Dr Nielssen in February 2009, the offender was next interviewed by Dr Allnutt, at the request of the Crown, in May 2009. (I note by this time the offender had resumed hormone replacement therapy under the care of her treating endocrinologist and was maintained on reducing doses of Seroquel, a treatment for anxiety. Her weight, which had increased from 85kg to 130kg whilst in custody, had also stabilised although I note that when she saw Dr Skinner in August 2009 she had gained another 20kg. Other physical side effects of the hormone replacement therapy were noted.) 33 She told Dr Allnutt of what she described as an extreme reaction to her sister's persistent domination of her parents to the extent that she thought she hated her sister because she was bad for the family and so thought of killing her. While she debated in her mind whether that was right or wrong, she did conclude that if she killed her sister her parents would, as she described it, "get over it". While she felt extreme anger towards her sister she said, so far as she could recall, her thinking processes were otherwise normal. 34 She told Dr Allnutt that after her sister blocked access to the internet, which she interpreted as another act of domination, she finally resolved to kill her sister. Her account of the killing to Dr Allnutt is coincident in what she told Dr Nielssen. Importantly, however, in what she said to Dr Allnutt there is revealed every indication of the offender detaching herself from the reality of what she was doing. After the killing she thought "this is a crime scene (but) it doesn't look like TV". The offender's medical and psychiatric history 35 The offender has suffered from congenital adrenal hyperplasia (CAH), a genetic disorder which affects the function of the adrenal glands, in particular the ability of the glands to synthesise the steroid hormones to normal levels. Without appropriate medication CAH is potentially life threatening especially where there is an intercurrent illness since the hormones naturally produced in the adrenal glands are critical for survival. She has been maintained on a range of corticosteroid based medications since early childhood to replace the hormones that are not naturally synthesised by her adrenal system. The medication also assists in the body's conservation of salt and represses the production of excess levels of testosterone, a feature of the condition. A side effect of the medication is very significant weight gain. 36 As a young child the offender was treated by a paediatric endocrinologist, Professor Martin Silink. In a report of 12 December 2008 Professor Silink recorded that as a child the offender underwent multiple surgical procedures to enable her to develop and function as a female consistent with her chromosomal female gender. This was accompanied by regular reviews of her hormone replacement therapy. By the age of 10 the offender's height and weight ratio were such that she was referred to the Adolescent Medical Unit at Westmead, although no significant weight loss was achieved at that time. 37 Throughout early adolescence she continued to gain weight significantly out of ratio to her height. Professor Silink reported that from the age of 15 her hormonal condition was not well controlled. The offender admitted that she did not always adhere to her treatment regime, it would appear because of what she understood to be her cortisone-induced obesity and associated self-consciousness. Professor Silink's efforts to vary her medication whilst still maintaining her hormone levels were not entirely successful, in part because of her non-compliance. He last saw the offender when she was 16, at which time he considered her hormone levels remained unsatisfactory. 38 In October 2005, when the offender was 18, Professor Silink referred her to Dr Holmes-Walker, an endocrinologist at the Adult Endocrine Unit at Westmead Hospital, a specialist with particular expertise in the management of CAH in adults. Dr Holmes-Walker was the offender's treating doctor from that time to the date of the offence. She continues to monitor and review her condition in association with Justice Health. 39 In her report of 17 December 2008 Dr Holmes-Walker noted that the offender's history of poor adherence to the treatment regime essential for the management of her condition emerged during early and mid adolescence. She also noted that in the initial 12 months after her referral the offender required increasing doses, initially of the corticosteroid dexamethasone and thereafter to the more potent corticosteroids, prednisone and fludrocortisone, to achieve adequate suppression of testosterone which had by that time become extremely high. There was no suggestion, however, that her fluctuating hormone levels were productive of any shift in her psychiatric state or that her ability to function was otherwise compromised at that time. I note that from the many high school friends and staff members whose testimonials were tendered on sentence that the offender gave every indication of coping admirably with the social and emotional pressures associated with adolescence despite her obesity and the limits this imposed on her physical fitness. 40 During her first 18 months at university the offender's hormones were returned to, and maintained at, normal levels under Dr Holmes-Walker's supervision and management. 41 Despite the offender's failure to attend regular follow-up appointments for 12 months from August 2007 until the date of the offence, Dr Holmes-Walker received blood tests in February 2008 which indicated that she was adhering to her pharmacological regime consisting at that time of 15 mg of prednisone twice a day and 600 mcg of fludrocortisone twice a day. 42 Dr Holmes-Walker first noted symptoms of the offender's mood disorder when she presented for a review on 5 August 2008. She recorded that the offender admitted that she had not been taking her medication for over a month. Her blood tests confirmed that she had ceased all medication. She demonstrated marked emotional lability and mood swings and reported feeling depressed although she did not report any suicidal ideation. She had failed her university exams in the previous semester. On examination Dr Holmes-Walker noted that her speech was pressured and her emotional lability suggested hypomania. She was encouraged to reinstate daily doses of prednisone and fludrocortisone and to resume taking the contraceptive pill as she had ceased menstruating, also as a result of non-adherence to the hormone replacement therapy. Dr Holmes-Walker was sufficiently concerned with the offender's mood disturbance to write to her general practitioner with a view to the offender being referred for psychiatric intervention since the offender refused the referral offered by Dr Holmes-Walker. 43 Neither of her parents noticed behaviour that caused them concern, or caused them to suspect she had ceased her medication or was even non-compliant with it. To the contrary. While her father noted that she was losing weight he believed she was succeeding at university and that she generally seemed more capable and positive. He did notice an increase in her energy levels and that overall she seemed more effervescent but he considered these changes were secondary to weight loss and improved fitness. He was unaware that she was experiencing any emotional difficulties or perceptual disturbances of the kind that she has since reported upon at length to the consulting psychiatrists. 44 The offender attended on Dr Holmes-Walker for review on 2 September 2008. This was the last review before the date of the offence. Blood tests on that occasion indicated that while her hormone levels had not returned to normal, they were at more balanced levels than the previous month, indicative of the fact that she had at least been taking some medication, if not in the prescribed doses. The offender reported that she continued to feel depressed and that as a result she would sometimes forget her medication in the evening. Although Dr Holmes-Walker noted that the offender described reduced hypomania, she expressed the caveat that from her experience of treating the offender she was someone who endeavours to please her treating doctors and, accordingly, may not be a reliable historian. 45 Despite being unable to cite any scientific literature on the impact of non-compliance with hormone replacement therapy and the related increase in testosterone levels on behaviour in women with CAH, Dr Holmes-Walker concluded that it was possible that the hormone disturbances which occurred as a consequence of the offender ceasing her medication for at least a month in July 2008 may have exacerbated an underlying or pre-existing psychiatric disturbance. She also noted that high levels of testosterone could contribute to increased aggression, particularly given that the offender's levels had been well controlled up until February 2008 but by August the fourfold increase in testosterone reached levels equivalent to those of a normal adult male. 46 Dr Nielssen prepared a report dated 21 January 2009 in which he assessed the offender's medical and psychiatric history. He took into account Dr Holmes-Walker's views. 47 In that report Dr Nielssen noted that in the 12 months prior to the offence the offender claimed to have reduced the medication prescribed by Dr Holmes-Walker in order to lose weight and gain strength. The offender claimed to have lost 60kg in weight in that time as a result of a combination of exercise, diet and not taking her medication. She described herself as a 20 year old girl who looked like a gladiator. She told Dr Nielssen that in the weeks leading up to the offence she knew she was supposed to be taking a daily dose of replacement hormones as well as the contraceptive pill to reinstate her menstrual cycle. In response to questions about effects on her behaviour as a result of her non-adherence to treatment, the offender said: "I don't know for sure … I felt things more … I was happy and excited … more frustrated … Mum said I was aggressive … I just felt more confident". 48 The offender later described an "upswing" in mood in the second half of 2008 which she again attributed to reducing her medication, combined with a fitness regime. She said she did not know if her improved mood was due to the effect of hormonal changes from ceasing her medication or the improvement in self-esteem associated with losing weight and improving her level of fitness. On the other hand, she also experienced feelings of depression which she attributed to the unrequited infatuation with her close friend and confidante. She claimed that she had become depressed when she was forced to accept that her friend was heterosexual and that there was no prospect of a romantic relationship with her. She said she suffered a loss of motivation and a consequent decline in her academic performance. 49 In the weeks after the offence the offender said that she still felt increased energy, accompanied by feelings of confidence, strength and creativity. This was consistent with Dr Nielssen's assessment of the offender's mood being abnormally elevated at the initial interview in November 2008, when she laughed at jokes of her own making and made a number of grandiose assertions about her own mental ability and creative potential that were typical of mania. He observed that she spoke rapidly in a loud voice and her account included many irrelevant asides, also consistent with her manic state. 50 At the second interview, two months later, Dr Nielssen observed that the offender presented with a much calmer and less elevated mood, however he still described her as being abnormally cheerful. He noted that she appeared distressed when she spoke of her sister's death and that she was also more rational when considering the effect of her actions on others and her current circumstances as a remand prisoner. Nevertheless, he described her as being hyper alert, answering questions before they had been completed. He considered her registration and retrieval of information to be largely unimpaired, although the pace of her thoughts led to gaps in information and she reported impaired memory of the fatal assault. 51 Based on her abnormally elevated mood and her reported depression, Dr Nielssen diagnosed the offender as suffering from a manic phase of bipolar disorder, together with psychiatric sequelae of untreated CAH at the time of her offending. 52 Despite being unable to refer to any published research on adult psychiatric disorders associated with CAH, or any reports of CAH associated with mania, Dr Nielssen noted the reported association between treatment with high doses of corticosteroids and acute psychiatric disturbances, including mania and delirium. Dr Nielssen concluded that in light of what he regarded as the offender's emerging psychotic illness at the time of the offence, her capacity for logical thinking and her ability to judge right from wrong were impaired. 53 As I have noted, the offender was interviewed by Dr Stephen Allnutt on 25 March 2009 and 11 May 2009 at the request of the Crown. As with the report of Dr Nielssen, he also noted that the offender's failure to strictly comply with her pharmacological regime extended for a period of 18 months prior to the offence, graduating to a total withdrawal in the months before the offence before she resumed taking some medication in the weeks before the offence, albeit at unregulated doses. Dr Allnutt also noted the offender's depressive symptoms and reduced motivation in early 2008 and that her mood had deteriorated when she attended on Dr Holmes-Walker in August and September of 2008. He accepted Dr Holmes-Walker's observations that she was experiencing extreme emotional instability at this time. 54 Despite the consistency of his findings concerning the offender's deteriorating mood disorder and the possibility that hypomania could cause a person to believe that their decisions are correct as a result of "grandiosity", which in turn could be regarded as a compromised capacity to judge right from wrong, Dr Allnutt was of the opinion that there was insufficient evidence to conclude that the offender's capacity was significantly impaired, as her feelings towards her sister were not delusional but reflective of sibling rivalry and some enmity. In particular he noted that her plans to kill her sister followed by hesitancy suggested she maintained adequate capacity to control her actions. 55 At the request of the offender's legal representatives, she was then examined on 24 June 2009 by Dr Bruce Westmore. He concluded that the offender was suffering from a mood disorder at the time of the offence which substantially impaired her capacity to control her behaviour. 56 The Crown then sought a further opinion from Dr Yvonne Skinner. She examined the offender on 10 August 2009. Although she disagreed with Dr Nielssen's opinion that the offender was suffering from an emerging psychotic illness at the time of the offence, she agreed with Dr Nielssen and Dr Westmore that the offender was suffering from a mood disorder at that time. Dr Skinner described the disorder as a corticosteroid-induced mania, caused by either or both intermittent dosage or withdrawal from the hormone treatment regime. She further noted that high levels of testosterone might have aggravated her mood disorder contributing to the overt displays of aggressive behaviour which ultimately translated into the decision to kill her sister by stabbing her. Despite agreeing with Dr Allnutt that there was evidence of pre-planning, and some evidence that the offender had a capacity to control her actions and to know right from wrong, Dr Skinner nonetheless concluded that her ability to control herself was substantially impaired by an abnormality of mind from her underlying medical condition. 57 In light of the advantage Dr Skinner enjoyed in being in a position to formulate her opinion after a considered review of the opinions of her eminent peers, the Crown submitted that her conclusion most accurately encapsulates the medical opinion bearing upon the issue of substantial impairment and the opinion I should adopt for sentencing purposes. Substantial impairment by abnormality of mind 58 Section 23A of the Crimes Act 1900 provides that: "(1) A person who would otherwise be guilty of murder is not to be convicted of murder if: (a) at the time of the acts or omissions causing the death concerned, the person's capacity to understand events, or to judge whether the person's actions were right or wrong, or to control himself or herself, was substantially impaired by an abnormality of mind arising from an underlying condition, and (b) the impairment was so substantial as to warrant liability for murder being reduced to manslaughter." 59 The Crown submitted that it was in relation to the offender's compromised capacity to control herself as a result of her mood disorder that ultimately led to the commission of the offence, rather than a failure to understand right from wrong or to clearly assess and comprehend the insignificance of the disputes with her sister which resulted in her planning to kill her and arming herself in preparation and anticipation of achieving that objective. 60 In the ultimate analysis I am satisfied that the submissions of the Crown and Mr Stratton SC do not materially differ as to the extent to which the offender's mental state reduces her criminal culpability for her sister's death. They both accept that at the time of the fatal stabbing her culpability was substantially mitigated by her mental state irrespective of whether it compromised her capacity to make a reasoned assessment of the events leading up to the stabbing, including her perception of her sister's behaviour and how she might best deal with it; to discriminate between right and wrong when she made the decision to stab her sister with the intention of killing her and when she equipped herself to achieve that objective; or her capacity to control her actions when, on the morning of the killing, she planned to kill her sister her internet access was blocked. In my view, it was most likely the fusion of each of these correlatives. Subjective circumstances 61 The offender tendered several references from family friends and those who have had school, church or community related interaction with her. The references were in large measure consistent with the account provided by the offender's mother, namely that she had always been a gentle, loving, considerate and caring person, devoted to her family and friends and that threats of violence or violent behaviour of any kind was completely out of character. 62 This is exemplified by the fact that when she attended Methodist Ladies College Junior School she held the role of Junior School Captain. She was elected to that position, not because she was talented at sports or academically gifted, but because she was regarded by her teachers and peers as kind, caring, outgoing and having a generally positive attitude. During her time in the Junior School the offender would often discuss her condition and the medical issues it gave rise to openly with her teachers. 63 At Methodist Ladies College Senior School the offender was well regarded for her selflessness, her concern for others and her deep social conscience. She was actively committed to charitable causes such as fundraising and volunteering to assist handicapped children and the homeless. She involved herself in extracurricular activities such as the school chess club and Editorial Committee for the school magazine. In 2005, her final year at high school, she was awarded the position of Senior Prefect. Her teachers described her as keeping a small group of friends but having a strong sense of belonging to the wider school community. 64 Her friends conceded that the offender was at times the victim of bullying but described her as responding to her aggressors in a dignified manner. She used her experiences of being bullied to assist younger students through a mentoring programme. In her final year of high school she experienced an episode of bullying that caused her considerable sadness but which she dealt with by arranging a peer mediation with two other students. One of those two students described the offender's treatment of this particular episode as indicative of her ability to empathise and communicate her emotions in a measured and reasonable way. 65 Despite not receiving a sufficiently high entrance score from her Higher School Certificate, in 2006 she was accepted to the Australian Catholic University on the basis of her commitment to extracurricular activities and other non-academic achievements. 66 When beginning her university studies she was described as being greatly enthusiastic about her chosen course and subjects and generally content with the state of her life. Sentence 67 In considering the sentence to be imposed I cannot overlook the fact that a young woman has lost her life. In this case, because of the relationship between the offender and the deceased, their parents suffer a compound loss and a compound tragedy. In their understandable desire to accept the tragic past and move forward as parents and partners it is open to them to accept the finding of this Court that were it not for the complexities inherent in the offender's underlying genetic condition, and the potential for her psychiatric state to be seriously undermined by her unilateral interference with a carefully prescribed and closely monitored regime of potent chemical hormones, this offence and the horrific death of their youngest child would never have occurred. I extend my sympathy to them both and to the members of their extended family. 68 I have carefully considered the detailed reports of the four eminent psychiatrists from which both counsel agree an informed assessment as to the criminal culpability of this offender can be safely made for sentencing purposes. Counsel also agree that there must be appropriate recognition of the established sentencing principles in s 3 of the Sentencing Act, in this case, in particular, the public denunciation of the deliberate and intentional taking of the life of another. They also agree that the established line of authority, of which YS v R [2010] NSWCCA 98 is a most recent example, dictates the principled approach to sentencing when mental illness is causally connected to the commission of an offence. In this case I am satisfied that the need for general deterrence has a negligible operation, given that the medical condition which gives context to the offending is a rare condition and the ways it impacts on the mental functioning of adult women who unilaterally elect to moderate or change their medication is not commonly encountered. 69 The fact that the offender's moral culpability is reduced because of her illness does not mean that she will not be sentenced to imprisonment. In particular, I emphasise that the impairment operating at the time of the killing does not of itself reduce the offence of manslaughter to a less serious type of manslaughter or one requiring a lesser punishment, any less than it negates her responsibility for her actions. Manslaughter, whatever form it takes, constitutes unlawful homicide. In addition, I am not persuaded in this case that her condition, now controlled, will necessarily make her time in custody more onerous such as might warrant reducing her sentence beyond what the circumstances of the case otherwise require. In that regard I note the observations of Dr Skinner that she is receiving psychiatric care but is no longer contained in the mental health unit. The offender also told Dr Skinner that she has adjusted to her custodial circumstances and that she has been occupying her time writing letters, listening to music and reading. She is also undertaking studies by correspondence. 70 Dr Nielssen interviewed the offender a third time on 26 February 2010, more than a year after he first saw her, to prepare an updated report on her condition and prognosis in light of the Crown accepting her plea of guilty to manslaughter. In response to questions asked about changes in her outlook or perception since resuming hormone replacement therapy in custody, the offender told Dr Nielssen that her thoughts were less aggressive and not as rapid and flighty. She said that she had noticed a change in the quality of her thoughts, from having what she described as a masculinised brain, being strategic in her thinking and obsessed with computer games to thinking about having a family. 71 When asked about her state of mind at the time of the offence, as expressed in her text messages to her friend and what she had said to police and corrective services officers following her arrest, the offender said she realised how bizarre her behaviour and thinking had become and well appreciated the need to be strictly compliant with her medication despite the gross side effects of the high doses of cortisone steroids she is required to take. She is no longer being administered anti-psychotic medication. In Dr Nielssen's view that illness was probably secondary to her mismanagement of her underlying medical condition. Dr Nielssen gave evidence that her above average intelligence and sustained insight into the risks that attend non-compliance with drug therapy on her eventual release allowed him to be confident she would not re-offend. I accept that evidence. I also note that her parents are supportive and visit her regularly. With their continued support I assess her prospects of rehabilitation as most promising. 72 In imposing sentence I am required to take the plea of guilty into account. In this case I propose to allow a discount of 25 per cent. The Crown does not submit otherwise. I am also satisfied that because of the offender's relative youth and prospects of rehabilitation I should exercise the discretion in s 44 of the Sentencing Act to vary the statutory ratio between the non-parole period and the balance of term. This will permit her a slightly longer period on parole so as to ensure that her continued and strict adherence to her drug therapy is closely monitored as she adjusts to her return to the community. 73 Kathleen Worrall I sentence you to imprisonment for a non-parole period of 4 years and 3 months commencing on 10 October 2008 and expiring on 9 January 2013 and a balance of term of 1 year and 9 months expiring on 9 October 2014. ********** DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment or decision. The onus remains on any person using material in the judgment or decision to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court or Tribunal in which it was generated.