ABSTRACT
This chapter provides an overview of the concept of mental illness and criminal responsibility and provides the origin of the insanity defence law. It highlights the insanity defence, including its essential elements, the special verdict, and the disposition of insanity acquittees. The insanity defence may be raised by a defendant who supposedly suffered from a mental abnormality at the time of committing the alleged offence. Defect of reason can be proven on the ground that the defendant's power of reasoning, as well as his or her ability to make rational choices and decisions, is severely compromised. The defect of reason must arise from a disease of the mind. The criminal law in Hong Kong, just like in Britain, provides a rebuttal of the presumption of sanity. One central feature of both English and Hong Kong legislation is the presumption that every man is sane and should be held accordingly for performing any act that contravenes the law.
