Serious mental illness

Current definition

December 2023

Severe mental illness - of specified severity

A definite diagnosis by a consultant psychiatrist of any of the following:

• bipolar affective disorder;
• delusional disorder;
• schizo-affective disorder; or
• schizophrenia.

The diagnosis has resulted in at least two of the following occurring within 12 months of each other:

• symptoms lasting at least a year or requiring continuous therapy or medication to control them;
• in-patient admission to a psychiatric ward, on the advice of a consultant psychiatrist, for at least 14 consecutive nights, or continuous home care by a Crisis Resolution and Home Treatment Team for 14 consecutive days, requiring at least 2 visits per day; or
• a court order being made by the Court of Protection under the Mental Capacity Act 2005 (England & Wales), Adults with Incapacity (Scotland) Act 2000 or the Mental Capacity Act (NI) 2016 (Northern Ireland).

For the above definition the following are not covered:

• delirium where there is no underlying psychiatric disorder; and
• conditions caused by, or exacerbated by, alcohol or drugs.