A significant number of people are not detained in hospital following assessment under the Mental Health Act 1983 (MHA) for possible detention. However, since amendments in 2007, some studies show an increase in total patient detentions. There is currently a lack of published research describing both outcomes and their affecting variables.

To determine rates, outcomes and affecting variables of MHA assessments in Norfolk, 2001–2011.

This observational study involved data collection from all 11,509 referrals for detention assessment under the MHA. Data was collected by Norfolk Social Services from 2001–2011 including age, gender and marital status.

Following assessment, 6903 (60.0%) were admitted; of those, 1157 (16.8%) were voluntary and 5746 (83.2%) were detained; 4606 (40%) were not admitted. Admission rates for males (50.4%) and females (49.5%) were similar. Detention rates increased with age: 37.6% of < 18s; 47.1% of 18–64s and 61.4% of 65+. A greater proportion of married (57.5%) and widowed patients (58.2%) were detained, compared with patients who were single (48%). Accommodation status showed 52% of those living with other were detained versus 43.9% of those with no fixed abode.

The finding that a higher proportion of married than single people, and of those living with others versus living alone, were detained following assessment is unexpected but significant and needs further investigation.

The authors have not supplied their declaration of competing interest.