Is dementia a mental illness?
OBJECTIVE: To examine whether dementia is a mental illness. METHOD: An analysis of decisions in the Supreme Court of New South Wales that dementia per se was not a mental illness in terms of the 1958 Mental Health Act. A brief review of the extrusion of other diseases from psychiatry. RESULTS: Concepts in legislation are based on a dichotomy between mental infirmity and mental illness that has changed over time. This change is the result of shifting perceptions about the basis of illness and disease and the causation of mental symptoms. Mental health legislation is aimed as much at social control of feared behaviour as protecting the ill/incompetent. Guardianship legislation offers a more holistic response that better meets the patient's needs and could be extended to supplant mental health legislation. CONCLUSIONS: Dementia's departure from mental illness reflects psychiatry's continuing marginalization within medicine on an outdated mind/body or illness/disease split. This underlines one of the psychiatrist's roles as the vehicle to 'medically' explain abnormal behaviour. This model means that behaviour, once explained in terms of disease as opposed to illness, can be moved from the direct responsibility of psychiatry into other areas of medicine. Paradoxically, this suggests that the future of psychiatry will be in a completely different direction from its current biological focus.