Behavioural symptoms among people with severe and profound intellectual disabilities: a 26-year follow-up study

Very little is known about the natural history of challenging behaviour and psychiatric disorder in people with severe and profound degrees of intellectual disability.

To clarify the natural history of challenging behaviour and psychiatric disorder in this population through a longterm prospective cohort study over a 26-year period.

One hundred individuals with severe or profound intellectual disability were randomly selected in 1975. Their behaviour was recorded through carer and psychiatrist ratings using the Modified Manifest Abnormality Scale of the Clinical Interview Schedule. The presence and severity of psychiatric disorder were also recorded. The study was repeated in 1981/82 and 1992/93. We repeated the study again in 2001, supplementing the original observational data with the Checklist of Challenging Behaviour.

Behavioural symptomatology is remarkably persistent, particularly stereotypy, emotional abnormalities, eye avoidance and overactivity, although the severity of overall psychiatric disorder does show some abatement through time.

These findings influence the prospects of success in relocating adults with severe and profound degrees of intellectual disability back into the community.