The reason why some specialist mental health professionals are eligible to undertake this role is broadly to avoid excessive medicalisation of the assessment and treatment for individuals living with a mental disorder, as defined by section 1 of the Mental Health Act 1983. It is the role of the AMHP to decide, on the medical recommendations of doctors (or a doctor for the purpose of section 4 of the Act), whether a person should be detained under the Mental Health Act.