ABSTRACT
Definitions of mental illness are notoriously difficult to draft. If they are framed too narrowly they deny services to people. If they are too broad they may result in unnecessary intervention. The ICD-10 definition – ‘a general term which implies the existence of a clinically stigmatising set of symptoms associated with distress … and with … interference with personal functions’ – and classification of diseases that fall under the rubric of mental illness exemplify a broad definitional approach, while the New South Wales 1990 Mental Health Act definition (Schedule 1) is narrow, as it excludes less severe, but common, forms of mental illness such as anxiety disorders:
mental illness is defined as a condition characterised by the presence of symptoms such as delusions, hallucinations, serious disorder of thought form, a severe disturbance of mood, or sustained or repeated irrational actions, which seriously impairs, either temporarily or permanently, the mental functioning of a person
