Risk of mental disorders in subjects with intellectual disability in the Lundby cohort 1947–97

Abstract

The Lundby Study is a prospective cohort study, which has followed a Swedish unselected community sample between 1 July 1947 and 1 July 1997. The aim was to study the risks of mental morbidity and different DSM-IV disorders in subjects with intellectual disability (ID) in the Lundby cohort between 1 July 1947 to 30 June 1997. The diagnosis of ID was re-evaluated according to DSM-IV in subjects who had been considered to have ID between 1947 and 1997. Multiple sources of information were used to obtain best estimate consensus diagnoses of mental disorders. The relative risk of mental disorder was 1.34 in subjects with ID as compared with the reference group. Dual diagnosis was more prevalent in mild ID than in moderate ID. No subject with severe ID was diagnosed with mental disorder. The cumulative incidence of any mental disorder in subjects with ID was 44%. The most common DSM-IV diagnoses were: Mood Disorders (11.5%), Anxiety Disorders (11.5%), Schizophrenia and Other Psychotic Disorders (8%), Mental Disorder NOS Due to a General Medical Condition (8%), Dementia (3.8%) and Alcohol Abuse (1.9%). Mental disorders were more common in subjects with ID than in the reference group.

Psychiatric care utilization among older people with intellectual disability in comparison with the general population: a register study

“…People with intellectual disability (ID) have a higher risk for psychiatric disorders than the general population [1, 2]. Thus, in a setting where people with ID have access to health care on the same terms as the general population, a higher psychiatric care utilization would be expected.…”

Medium range cognitive impairment (MeRCI) hypothesis for psychosis formation: evidence from epidemiological studies and recent molecular genetic developments

“…In the Lundby cohort, the cumulative incidence of psychotic disorders was 8%, which is significantly higher than in the general population. 12 In this study, psychiatric disorders, including schizophrenia, were more prevalent in individuals with mild than in those with moderate intellectual disability. In another study specifically designed to compare the rate of psychopathology in 2 community groups with varying degrees of intellectual disability, it was reported that psychotic disorders were significantly overrepresented in patients with mild/moderate than in those with severe/profound intellectual deficits.…”

Early intervention in psychosis: clinical aspects of treatment

“…Individuals with intellectual disability (IQ < 70) are at higher risk of schizophrenia and other psychotic disorders than the general population (Bouras 2004;Nettelbladt 2009), with pregnancy and birth complications likely to be relevant aetiological factors in psychosis (O'Dwyer 1997). Diagnosis benefits from specialist input from intellectual disability services, and shared care is essential in achieving good outcomes.…”