Not guilty by reason of insanity

Not guilty by reason of insanity

The ‘not guilty by reason of insanity’ defence differs from the issue of fitness to plead because it involves unfitness at the time of the offence, rather than at the time of trial. If the accused was suffering from a disability of the mind at the time of the offence, the accused may be able to raise a defence of “insanity” during trial. The legal basis for this defence is found in section 74 of the Criminal Procedure Ordinance, and the understanding of this defence is based on the M’Naghten Rules from the UK. The M’Naghten rules set out the circumstances in which an accused will be held not to have been legally responsible for their conduct. Specifically, it must be proved that, at the time of the offence, the accused was “labouring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing; or, if he did know it, that he did not know he was doing what was wrong” (see M’Naghten’s Case 8 Eng. Rep. 718, 719).

Not knowing the ‘nature and quality’ of the act has been understood to refer only to the physical character of the act; in other words, the person did not know what they were doing. For example, a person who strangles another believing they are squeezing a lemon, or throws a baby into a fire thinking it is a log, does not grasp the act’s true nature. Not knowing he was doing what was wrong means that the person did not know what they did was legally wrong (see R v Windle (1952)).  For example, a man kills his wife, fully aware that it is against the law to do so. Even though he was under a delusion that he was acting morally correctly by releasing her from suffering, he cannot rely on the insanity defence in this case because he knew the act was legally wrong.

If the jury finds that the accused has proven on a balance of probabilities that the criteria in the M’Naghten Rules are met, the jury shall return a special verdict of “not guilty by reason of insanity”.

Disposition / Sentence

If a person is:

1. found to be unfit to plead, and have committed the acts of the offence with which he has been charged; or 
2. found not guilty by reason of insanity,

there are several disposal options contained in section 76 of the Criminal Procedure Ordinance:

1. Order for admission to Correctional Services Department Psychiatric Centre (i.e. Siu Lam Psychiatric Centre) or mental hospital (‘hospital order’): by law, the duration of a hospital order should not exceed the maximum sentence that the court or magistrate could have imposed for the offence with which the person was charged. In practice, however, hospital orders may continue for an indefinite period, depending on the medical evidence and the views of the doctors involved.
2. Supervision and treatment order (Part IIIB Mental Health Ordinance): place the accused under the supervision of the Director of Social Welfare, for maximum 2 years.
3. Guardianship order (Part IIIA Mental Health Ordinance): place the accused under the guardianship of the Director of Social Welfare, for maximum 1 year.

The person can also be absolutely discharged.