It is settled that serious psychiatric illness not amounting to insanity is relevant to sentencing. In R v Tsiaras [1996] VicRp 26; [1996] 1 VR 398 at 400, Charles and Callaway JJA and Vincent AJA said that this was so in at least the following five ways:
'First, it may reduce the moral culpability of the offence, as distinct from the prisoner's legal responsibility. Where that is so, it affects the punishment that is just in all the circumstances and denunciation of the type of conduct in which the offender engaged is less likely to be a relevant sentencing objective. Second, the prisoner's illness may have a bearing on the kind of sentence that is imposed and the conditions in which it should be served. Third, a prisoner suffering from serious psychiatric illness is not an appropriate vehicle for general deterrence, whether or not the illness played a part in the commission of the offence. The illness may have supervened since that time. Fourth, specific deterrence may be more difficult to achieve and is often not worth pursuing as such. Finally psychiatric illness may mean that a given sentence will weigh more heavily on the prisoner than it would on a person in normal health.'
Of course, moral culpability would only be lessened where there is a causal connection between the psychiatric illness and the commission of the offence or offences, in the sense that the psychiatric condition must have contributed to the commission of the offence: R v Richards [1999] WASCA 105; R v Paparone [2000] WASCA 127; (2000) 112 A Crim R 190 at [50] and [51] per Murray J; and R v Payne [2002] WASCA 186; (2002) 131 A Crim R 432 at [40]. It must necessarily be the case that, the greater the contribution of the psychiatric illness, the more the moral culpability will be lessened. To the extent that there is a moral lessening of culpability, that should be reflected in the penalty imposed, as it often has been: see, for example, R v Juli (1990) 50 A Crim R 31 at 37; R v Hurd [1988] TASSC 54; (1988) 38 A Crim R 454 at 461, 465; Tsiaras, above, at 400; R v Balchin (1974) 9 SASR 64 at 68; R v Reynolds (1983) 10 A Crim R 30; and Lauritsen v The Queen [2000] WASCA 203; (2000) 22 WAR 442 at 456 - 459.
As to personal deterrence, as is implicit from what was said in Tsiaras, much depends upon the nature and effect of the illness. The notion of personal deterrence assumes some rational analysis or reasoning in the course of comparing the likely gains from the crime against the prospect, and likely severity, of punishment, and, where the illness affects the person's ability to make that analysis, there is no justification for affording that consideration the same measure of significance as it might have in the case of a well person: see Payne, above, at [43].
As to general deterrence, this is a factor which should often be given little weight in the case of an offender suffering from a mental disorder, such an offender not being an appropriate medium for making an example to others: R v Scognamiglio (1991) 56 A Crim R 81 at 86; Anderson v The Queen [1981] VicRp 17; [1981] VR 155 at 159. In an extreme case, considerations of general deterrence might be totally outweighed by other factors. However, in every case, the relevant factors must be balanced in a manner no different from that which is involved in every sentencing exercise: R v Letteri, unreported; CCA SCt of NSW; Library No 60497 of 1991; 18 March 1992 at 14, per Badgery-Parker J and R v Engert (1995) 84 A Crim R 67 at 70-71, per Gleeson CJ. [52] - [55]