Attention-deficit/hyperactivity disorder (ADHD) is associated with depression in young adulthood, and some evidence suggests that ADHD genetic liability may have a causal effect on major depression in later life, according to an article published in Psychological Medicine.

In the study, Lucy Riglin, PhD, of the division of psychological medicine and clinical neurosciences, MRC Centre for Neuropsychiatric Genetics and Genomics, Cardiff University, in Cardiff, Wales, United Kingdom, and colleagues obtained mental health data on 8310 patients from the Avon Longitudinal Study of Parents and Children. These data were used to examine the association between childhood ADHD at approximately 7 years of age with recurrent depression at ages 18 to 24 years. The investigators also performed 2-sample Mendelian randomization (MR) analyses to evaluate the associations between ADHD genetic liability and depression using previously published genome-wide association study (GWAS) data.

A total of 530 (6.4%) patients in the longitudinal cohort scored above the ADHD cutoff point at age 7 years, and 26.9% of patients had recurrent depression in young adulthood. The presence of ADHD in childhood was associated with a significantly increased risk of recurrent depression during young adulthood (odds ratio [OR], 1.35; 95% CI, 1.05–1.73; P =.02). This association persisted in an analysis adjusted for sex, early adversity, maternal education, and maternal depression (OR, 1.38; 95% CI, 1.07–1.79; P =.01).

According to MR analyses, the investigators observed a causal effect of ADHD genetic liability on subsequent major depression, such that with every unit increase in log-odds ADHD genetic liability, there was an approximately 21% increased risk in the odds for major depression (OR, 1.21; 95% CI, 1.12–1.31). An MR with a broader definition of depression demonstrated a weak influence of ADHD genetic liability on depression (OR, 1.07; 95% CI, 1.02–1.13).


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Based on these findings, the researchers emphasized that effective ADHD treatment may “help prevent the development of depression for some, especially when ADHD persists into adulthood, but that it is unlikely to consistently prevent the development of depression for all” patients.

Reference

Riglin L, Leppert B, Dardani C, et al. ADHD and depression: investigating a causal explanation [published online April 6, 2020]. Psychol Med. doi: 10.1017/S0033291720000665.