The association between severity of intellectual disability and psychiatric symptomatology.
BACKGROUND
Mental illness is more prevalent in people with intellectual disabilities (ID) than in the normal population. The association between mental illness and severity of ID is also of importance in the understanding and treatment of maladaptive and challenging behaviours. The aim of this study was to investigate the association between severity of ID and prevalence of mental illness.


METHODS
Using the Mini PAS-ADD, an instrument designed to identify psychiatric symptoms in people with ID, informants were interviewed about the presence of symptoms in 96 participants with moderate, severe and profound ID, and asked about the use of psychotropic medication.


RESULTS
Mental illness, particularly anxiety, depression and psychosis, was far more prevalent in participants with moderate ID than in people with severe and profound ID. The use of psychotropic medication was not significantly different between the groups.


CONCLUSIONS
The prevalence of psychiatric illness decreases with severity of ID. The usefulness of psychiatric illness models, in explaining maladaptive and challenging behaviours, also decreases with severity of ID. Drug treatment may become more complicated, and behavioural and environmental interventions may become relatively more important, as severity of ID increases.
Habiliteringstjenesten for voksne funksjonshemmede, Hedmark Naeringspark Bygg 15, 2312 Ottestad, Norway. Borge.Holden@sykehuset-innlandet.no
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Holden
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Gitlesen
D000328:Adult; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D006801:Humans; D001523:Mental Disorders / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D008875:Middle Aged; D011619:Psychotropic Drugs / Q000627:therapeutic use; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
D011619:Psychotropic Drugs