Mental health is a complex area of the law. Over half of the population of Australia has experienced some mental health condition during their life, and at least 15% of criminals have a diagnosed mental illness.

So how do the law and mental health interact?

The Mental (Forensic Provisions) Act 1990 (NSW) provides for a range of mental health defences available to criminal defendants.

Section 32 applications are used for a wide range of criminal offences, for example assault or dangerous driving. If successful, resulting in dismissal. Instead, the defendant will be discharged with conditions to continue treatment with a psychologist.

A McNaughton Defence is used for more serious criminal offences, for example murder. It requires proof on the balance of probabilities that:

• At the time of the offence, the defendant was suffering from a mental illness; and
• The mental illness caused the defendant to not know the nature and quality of their actions or understand the wrongness of them.

If successful, a defendant may be released with or without conditions, or placed in a mental health facility. The Mental Health Review Tribunal will review the person every 6 months to determine whether it is safe to release them.

Sane automatism can be proved where a person shows that their actions were involuntary due to an external factor, for example a psychological blow which is unlikely to recur. Insane automatism can be proved where a person shows their actions were involuntary due to a mental illness which is likely to recur.

Insane automatism usually results in the defendant being detained and reviewed by the Mental Health Review Tribunal to determine whether it is safe to release them.