Suicidality and Familial Liability for Suicide in Autism: A Population Based Study
Objectives: This study aimed to explore the gender specific risk of suicide attempt and suicide in ASD individuals with (ASD+ID) and without intellectual disability (ASD-ID), as well as the potential role of familial liability.
Methods: Swedish national registers were used to conduct a matched case-cohort study applying conditional logistic regression models. We identified 54168 individuals with ASD (ASD-ID n = 43570; ASD+ID n = 10598) recorded from January 1, 1987, to December 31, 2013, and 270840 controls matched for gender, age and residential information. We also compared risk of suicidal behaviour at three levels of family relatedness in 348192 relatives of individuals with ASD and 1740960 matched control relatives.
Results: Individuals with ASD-ID had an increased risk of both suicide attempt and suicide, even after adjustment for depression and attention-deficit hyperactivity disorder (ADHD). Females with ASD-ID had higher risk of suicide attempt and suicide as compared to males with ASD-ID. The risk was also increased in ASD+ID group regarding both attempted suicide and suicide, although to a lesser degree as compared to ASD-ID group. In comparison to controls, relatives of individuals with ASD had an increased risk of suicidal behaviour. First-degree relatives of individuals with ASD had significantly higher risk estimates of suicidal behaviour than second- and third-degree relatives.
Conclusions: Individuals with ASD are at increased risk of suicidal behaviour, in particular females without intellectual disability. Psychiatric comorbidities and shared familial risk factors are important explanations to the increased risk of suicidal behaviour in ASD. Clinicians treating patients with ASD should be vigilant for suicidal behaviour and consider treatment of psychiatric comorbidity.