Definition of Mental Disorder and Exclusions

In the 1983 Act, mental disorder is sub-divided into four categories:

  1. mental illness;
  2. mental impairment;
  3. severe mental impairment; and
  4. psychopathic disorder.

The definitions in the current Act for mental impairment and severe mental impairment include the requirement for the person to have "abnormally aggressive or seriously irresponsible conduct" in addition to having a learning disability, to protect this group of people from inappropriate use of the legislation.

The 1983 Act excludes certain behaviours from being seen in themselves as mental disorders. These are: promiscuity or other immoral conduct, sexual deviancy or dependence on alcohol or drugs.

The Draft Mental Health Bill defines mental disorder as "an impairment of, or a disturbance in, the functioning of the mind or brain resulting from any disability or disorder of the mind or brain". There are no exclusions to this wide definition of mental disorder.