Does pharmacotherapy for attention-deficit/hyperactivity disorder predict risk of later major depression?

This study's goal was to determine among youths with attention-deficit/hyperactivity disorder (ADHD) how the history of ADHD pharmacotherapy influenced the risk of developing major depressive disorder (MDD), compared to other commonly reported predictors.

Diagnostic and treatment history data were analyzed retrospectively in 75 youths 11-18 years old with definite or probable ADHD, enrolled in an observational study at a tertiary mental health clinic. Subjects with histories of MDD (H/o MDD) (n = 36) were compared to others who had never been depressed (Never-Depressed) (n = 39) regarding histories of ADHD pharmacotherapy, psychopathology and other potential covariates of MDD risk.

H/o MDD subjects reported longer delays before initiating ADHD pharmacotherapy, were more often female, reported having experienced more traumatic event types, and had higher rates of early anxiety and externalizing disorders. With all covariates allowed to enter a backward stepwise Cox regression of survival time till first episodes of MDD, only two variables remained in the model. The time-dependent variable, ADHD pharmacotherapy, prolonged survival times (p = .012), while having experienced more traumatic event types shortened them (p = .001).

This study provides preliminary evidence that pharmacotherapy for ADHD may have a protective effect in ADHD youths, reducing the risk of later MDD.