The provisions of this Act shall have effect with respect to the reception, care and treatment of mentally disordered patients, the management of their property and other related matters.

In this Act—

• "mental disorder" means mental illness, arrested or incomplete development of mind, psychopathic disorder and any other disorder or disability of mind and " mentally disordered" shall be construed accordingly;

• " severe mental impairment" means a state of arrested or incomplete development of mind which includes severe impairment of intelligence and social functioning and is associated with abnormally aggressive or seriously irresponsible conduct on the part of the person concerned and "severely mentally impaired" shall be construed accordingly;

• " mental impairment" means a state of arrested or incomplete development of mind (not amounting to severe mental impairment) which includes significant impairment of intelligence and social functioning and is associated with abnormally aggressive or seriously irresponsible conduct on the part of the person concerned and "mentally impaired" shall be construed accordingly;

• "psychopathic disorder" means a persistent disorder or disability of mind (whether or not including significant impairment of intelligence) which results in abnormally aggressive or seriously irresponsible conduct on the part of the person concerned;

and other expressions shall have the meanings assigned to them in section 145 below.

Nothing in subsection (2) above shall be construed as implying that a person may be dealt with under this Act as suffering from mental disorder, or from any form of mental disorder described in this section, by reason only of promiscuity or other immoral conduct, sexual deviancy or dependence on alcohol or drugs.