Prevalence and predictors of suicidal behaviour in a sample of adults with estimated borderline intellectual functioning: Results from a population survey

Background: We aimed to investigate, for the first time, rates of suicidal behaviour (ideation and acts) in people with borderline intellectual functioning in a general population sample, and to compare these to rates in people with normal functioning. Methods: We used data from the third Adult Psychiatric Morbidity Survey, carried out in England in 2007. It was designed to be representative of people living in private households. The analyses are based on 6872 individuals. Results: 1053 (16.1%) participants met criteria for borderline intellectual functioning. People with borderline intellectual functioning were more likely to report ever having made a suicidal attempt or to have harmed themselves without the intention of taking their own life (Odds Ratio for both 1.7, 95% Confidence Interval 1.3-2.2). These associations were no longer significant after controlling for income and age. Limitations: Our sample did not include people living in segregate environments, who were likely to display challenging behaviours, and have higher rates of self harm. Conclusion: The increased rates of suicidal behaviour found in people with borderline intellectual functioning were explained by younger age and socioeconomic disadvantages, although the association is likely to be complex. Our findings would strongly support targeting those at the lower range of intelligence with interventions for suicide prevention. (C) 2010 Elsevier B.V. All rights reserved.