An association between negatively biased response to neutral stimuli and antidepressant nonadherence

Our primary objective was to test whether negatively biased response to neutral physical or visual stimuli was associated with antidepressant nonadherence.

We surveyed 22 primary care adults receiving pharmacological treatment for depression. Somatoform complaints, in addition to interpretation of and response to neutral facial expressions (NFEs), were assessed with surveys. Seven response anchors to NFE were classified as "negative" or "neutral/positive." Antidepressant adherence was ascertained after 3 months by self-report and pharmacy refill records.

Elevated somatoform complaints were associated with early antidepressant discontinuation (P=.01). Exclusively negative emotional response to NFE, reported by 55% (12/22) of subjects, was associated with clinically significant missed antidepressant doses (R=-.69, P=.0004). Two multivariate models adjusted for depressive symptoms demonstrated that exclusively positive or neutral emotional response to NFE was associated with improved adherence relative to an exclusively negative response (beta=34.0, t=3.7, P=.002); the somatoform complaints subscale "health concerns" adversely influenced depressive symptom improvement (beta=-.3, t=-3.0, P=.008).

Negatively biased responses to neutral stimuli in the physical and visual axes were associated with early antidepressant discontinuation and missed doses, respectively. If substantiated, these initial findings might contribute to improved understanding and treatment of antidepressant nonadherence.