If a person raises mental illness successfully as a defence excluding criminal capacity
(defence of pathological incapacity), such person’s lack of criminal capacity is
exculpatory and results in his or her acquittal. The court in Ntshongwana v S
confirmed that section 78(1) of the Criminal Procedure Act 51 of 1977 provides the
requirements for the defence of pathological incapacity.1 Discuss these requirements
that must be present for this defence to succeed.
In order for the defence of pathological incapacity to succeed, the following requirements must be present:
1. Mental illness: The accused must have a mental illness or disorder that impairs their ability to appreciate the wrongfulness of their actions or to conform their conduct to the requirements of the law. This mental illness must be of such a nature that it renders the accused incapable of understanding or controlling their actions at the time of the alleged offense.
2. Lack of criminal capacity: The mental illness must be shown to have deprived the accused of the capacity to appreciate the nature and consequences of their actions, as well as the ability to distinguish between right and wrong. This lack of criminal capacity must be established through expert testimony and evidence presented in court.
3. Causation: The mental illness must be demonstrated to have been the direct cause of the accused's actions. It must be shown that the mental illness was the reason why the accused committed the alleged offense and that they would not have committed the offense if not for their mental illness.
4. Temporal connection: The mental illness must have been present at the time of the alleged offense. It is not enough to show that the accused has a mental illness at the time of the trial; there must be evidence to prove that the mental illness existed at the time of the offense and impaired the accused's mental capacity.
If all of these requirements are met, then the defence of pathological incapacity can be successfully raised, resulting in the accused being acquitted due to their lack of criminal capacity at the time of the offense.