It provides care and treatment in conditions of high security for patients from Scotland and Northern Ireland.

Although it was planned and financed as a facility for "mental defectives", it was first used as a military hospital, during the Second World War.

The War Office relinquished control of the hospital in 1948, when it became the State Institution for Mental Defectives.

Construction began in April 2008 and the new hospital facilities were officially opened on 26 June 2012.

[5] The hospital has an alarm system that is activated if any patient escapes to alert people in the vicinity, including those in the neighbouring town of Lanark, and local villages such as Ravenstruther and Forth.