Young adults with autism – particularly those with no intellectual disability – are at a higher risk of depression than their counterparts without autism, according to results of a Swedish population-based study.
Furthermore, the study found that young adults with autism spectrum disorders (ASD) also are at an increased risk of depression than their nonautistic siblings, reported Dheeraj Rai, MRCPsych, PhD, and his coauthors on JAMA Network Open Psychiatry.
“Because of the likelihood of a substantial overrepresentation of depression among individuals with ASD, a greater focus on timely identification and management of depression is important considering that it is a potentially treatable cause of distress, disability, and suicidal behaviors,” wrote Dr. Rai of the Centre for Academic Mental Health at the University of Bristol (United Kingdom) and his coauthors.
Previously, the burden of depression was thought to be high among individuals with ASD, but this is only the second longitudinal study to demonstrate an increased depression risk in adults with ASD, compared with the general population, the investigators wrote.
The study, called the Stockholm Youth Cohort, included data on children and young people who lived in Stockholm County, Sweden, between 2001 and 2011. The cohort included a total of 223,842 individuals who were followed until they were aged at least 18 years, of whom 4,073 had a diagnosis of ASD (mean age, 21.5 years; 65.9% male).
A total of 19.8% of individuals with ASD received a depression diagnosis between the ages of 18 and 27, compared with 6% of individuals with no ASD diagnosis, investigators found.
Depression diagnosis was more likely in those who had ASD with no intellectual disability, with an adjusted risk ratio of 4.28 (95% confidence interval, 4.00-4.58), compared with 1.81 (95% CI, 1.51-2.17) for ASD with intellectual disability, they reported.
The investigators also identified siblings of individuals with ASD using data from a Swedish registry. Individuals with ASD had more than a twofold greater depression diagnosis risk, compared with nonautistic full siblings (adjusted odds ratio, 2.50; 95% CI, 1.91-3.27).
“This association also seemed largely driven by an overrepresentation of depression in ASD without intellectual disability,” Dr. Rai and his coauthors wrote.
Those nonautistic siblings also had a somewhat higher risk of a depression diagnosis versus population controls, with adjusted risk ratios of 1.37 for full siblings and 1.42 for half siblings, they added.
“Studies identifying such pathways could assist in the development of preventive strategies or interventions,” they wrote.
Limitations of the study include the possibility of misclassification of depression diagnoses. Nevertheless, they said, the findings have implications for clinical practice and future research.
Dr. Rai reported receiving grants from The Baily Thomas Charitable Foundation, the National Institute for Health Research, and the Swedish Research Council for Health, Working Life and Welfare during the conduct of the study. His coauthors reported no other disclosures.
SOURCE: Rai D et al. JAMA Network Open. 2018 Aug 31. doi: 10.1001/jamanetworkopen.2018.1465.