Diverse diagnostic and behavioural patterns amongst people with a dual diagnosis

People who have both an intellectual disability and a mental illness diagnosis are gaining more attention in the mental health and developmental disabilities service systems. This interest is partly because of the challenging behaviours and the complexities of the problems in this population. The present study analyses the diagnoses, behaviour problems and demographic characteristics of a group of people with a dual diagnosis to determine if specific patterns are evident which distinguish this set of subjects. A group of 940 people who were part of a class action lawsuit in North Carolina, USA, were investigated. A factor analysis was conducted to determine whether or not distinct patterns or factors were evident. This analysis revealed six distinct patterns primarily based on the behaviour problems of this group and secondarily based on their diagnoses. These six factors are referred to as: (1) aggressive/disturbing behaviour; (2) withdrawal/asocial behaviour; (3) inappropriate behaviours; (4) sociopathic characteristics; (5) suicidal or runaway crises; and (6) pica disorder. The findings suggest that mental illness is a prominent characteristic of some of the six factors but not of others. Furthermore, an intellectual disability diagnosis and the particular level of intellectual disability are reflected very differently amongst all of these factors.