ADHD and depression: investigating a causal explanation. Issue 11 (6th August 2021)

• Record Type: Journal Article
• Authors: Riglin, Lucy; Leppert, Beate; Dardani, Christina; Thapar, Ajay K.; Rice, Frances; O'Donovan, Michael C.; Davey Smith, George; Stergiakouli, Evie; Tilling, Kate; Thapar, Anita
• Is Part Of: Psychological medicine. Volume 51:Issue 11(2021)
• Page Start: 1890
• Page End: 1897
• Publication Date: 2021-08-06
• Subjects: ADHD -- ALSPAC -- causal -- depression -- longitudinal -- Mendelian randomization; Psychiatry -- Periodicals; Medicine and psychology -- Periodicals; Clinical psychology -- Periodicals; 616.89
• DOI: 10.1017/S0033291720000665
• Languages: English
• ISSNs: 0033-2917

Abstract

Abstract: Background: Attention-deficit hyperactivity disorder (ADHD) is associated with later depression and there is considerable genetic overlap between them. This study investigated if ADHD and ADHD genetic liability are causally related to depression using two different methods. Methods: First, a longitudinal population cohort design was used to assess the association between childhood ADHD (age 7 years) and recurrent depression in young-adulthood (age 18–25 years) in N = 8310 individuals in the Avon Longitudinal Study of Parents and Children (ALSPAC). Second, two-sample Mendelian randomization (MR) analyses examined relationships between genetic liability for ADHD and depression utilising published Genome-Wide Association Study (GWAS) data. Results: Childhood ADHD was associated with an increased risk of recurrent depression in young-adulthood (OR 1.35, 95% CI 1.05–1.73). MR analyses suggested a causal effect of ADHD genetic liability on major depression (OR 1.21, 95% CI 1.12–1.31). MR findings using a broader definition of depression differed, showing a weak influence on depression (OR 1.07, 95% CI 1.02–1.13). Conclusions: Our findings suggest that ADHD increases the risk of depression later in life and are consistent with a causal effect of ADHD genetic liability on subsequent major depression. However, findings were different for more broadly defined depression.