Association of Obsessive-Compulsive Disorder With Objective Indicators of Educational Attainment: A Nationwide Register-Based Sibling Control Study.

Importance: To our knowledge, the association of obsessive-compulsive disorder (OCD) and academic performance has not been objectively quantified. Objective: To investigate the association of OCD with objectively measured educational outcomes in a nationwide cohort, adjusting for covariates and unmeasured factors shared between siblings. Design, Setting, And Participants: This population-based birth cohort study included 2 115 554 individuals who were born in Sweden between January 1, 1976, and December 31, 1998, and followed up through December 31, 2013. Using the Swedish National Patient Register and previously validated International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) codes, we identified persons with OCD; within the cohort, we identified 726 198 families with 2 or more full siblings, and identified 11 482 families with full siblings discordant for OCD. Data analyses were conducted from October 1, 2016, to September 25, 2017. Main Outcomes and Measures: The study evaluates the following educational milestones: eligibility to access upper secondary school after compulsory education, finishing upper secondary school, starting a university degree, finishing a university degree, and finishing postgraduate education. Results: Of the 2 115 554 individuals in the cohort, 15 120 were diagnosed with OCD (59% females). Compared with unexposed individuals, those with OCD were significantly less likely to pass all core and additional courses at the end of compulsory school (adjusted odds ratio [aOR] range, 0.35-0.60) and to access a vocational or academic program in upper secondary education (aOR, 0.47; 95% CI, 0.45-0.50 and aOR, 0.61; 95% CI, 0.58-0.63, for vocational and academic programs, respectively). People with OCD were also less likely to finish upper secondary education (aOR, 0.43; 95% CI, 0.41-0.44), start a university degree (aOR, 0.72; 95% CI, 0.69-0.75), finish a university degree (aOR, 0.59; 95% CI, 0.56-0.62), and finish postgraduate education (aOR, 0.52; 95% CI, 0.36-0.77). The results were similar in the sibling comparison models. Individuals diagnosed with OCD before age 18 years showed worse educational attainment across all educational levels compared with those diagnosed at or after age 18 years. Exclusion of patients with comorbid neuropsychiatric disorders, psychotic, anxiety, mood, substance use, and other psychiatric disorders resulted in attenuated estimates, but patients with OCD were still impaired across all educational outcomes. Conclusions and Relevance: Obsessive-compulsive disorder, particularly when it has an early onset, is associated with a pervasive and profound decrease in educational attainment, spanning from compulsory school to postgraduate education.