1. organic disorders, which are due to a general medical condition, and which are pathological and endogenous, and which therefore satisfy the criteria of the legal definition of insanity;
2. substance-related disorders, which are not necessarily pathological, endogenous or permanent, so that persons suffering from them are not necessarily legally insane;
3. schizophrenia and other psychotic disorders, which are pathological, endogenous and capable of depriving the sufferer of insight or self-control, and therefore satisfy the criteria of the legal definition of insanity;
4. personality disorders, which are not a consequence of disturbance of the psychic state, but rather of patterns of behaviour learned during the formative years, and which are discussed further below;[173] and
mood and anxiety disorders:
5. Mood disorders are capable of depriving the sufferer of insight or self-control, and may therefore satisfy the criteria of the legal definition of insanity.
Anxiety disorders do not affect ones ability to distinguish reality from unreality, and therefore are not psychotic in nature.
Dissociative orders, however, may deprive the sufferer of insight or self-control, and therefore may satisfy the criteria of the legal definition of insanity.[174]
The Interim Report of the Booysen Commission of Enquiry into the Continued Inclusion of Psychopathy as Certifiable Mental Illness and the Dealing with Psychopathic and Other Violent Offenders found that the retention of psychopathy as a mental illness in the Mental Health Act is not only scientifically untenable, but it is also not effective in practice.
In accordance with the recommendations of the Commission, section 286A of the CPA now provides for the declaration of certain persons as dangerous criminals, and section 286B for the imprisonment, for an indefinite period, of such persons.
Even before the Booysen Commission, however, the courts were not prepared to accept psychopathy, in and of itself, as exempting an accused from criminal liability, or even as warranting a lesser sentence on account of diminished responsibility.
In S v Mnyanda,[175] the accused was convicted of murder. In an appeal, he argued that his psychopathy should have been regarded as a mental illness, and thus as an mitigating factor.
The court found that the mere fact that an accused may be regarded as clinically a psychopath is not a basis on which he may be found to have diminished responsibility. Only when, in respect of a particular misdeed, it can be said that the psychopathic tendency was of such a degree as to diminish the capacity for self-control to such a point that, according to a moral judgment, he is less blameworthy, will the law recognise his diminished responsibility.
