Most people with a mental health condition live their lives without being affected by the Mental Health Act. For the relatively small number of people who experience more severe mental health conditions, the Mental Health Act 1983 provides the framework by which they can be admitted, detained and treated in hospital against their wishes.

The Act covers the rights of people while they are detained, how they can be discharged from hospital and what aftercare they can expect to receive. Part 3 of the Mental Health Act focuses on how the Act applies to the criminal justice system.

The Act covers England and Wales. The Mental Health Act 1983 was amended by the Mental Health Act 2007.

The Mental Health Act applies to people with mental disorder. Mental disorder is defined by part 1 of Act as ‘any disorder or disability of mind'. According to chapter 3 of the Mental Health Act Code of Practice, this definition includes conditions such as schizophrenia, depression, bipolar disorder, anxiety disorder, obsessive-compulsive disorder, eating disorders, personality disorders, autistic-spectrum disorders, organic disorders such as dementia, behavioural changes due to brain injury and mental disorders due to drug use. The definition includes learning disability only where it is associated with ‘abnormally aggressive’ or ‘seriously irresponsible behaviour’.