OBJECTIVE: This study reanalyzed data from a randomized placebo-controlled trial that failed to find an effect of the selective serotonin reuptake inhibitor escitalopram on neuroticism and state anxiety in a nonclinical sample. The purpose was to test for unique effects on two neuroticism factors, trait anxiety and mood instability, and to explore whether neuroticism moderated the effect of escitalopram on state anxiety.

METHODS: The sample included 80 adults who had a first-degree relative with major depression but without any psychiatric disorders themselves. Participants were randomized to escitalopram 10 mg/day or placebo for 4 weeks. Neuroticism was assessed with the Eysenck Personality Questionnaire (EPQ) and state anxiety with the Hamilton Anxiety Rating Scale (HAM-A).

RESULTS: The main effects on the neuroticism factors were not statistically significant, although there was a significant interaction such that the effect of escitalopram compared with placebo on HAM-A scores was statistically significant in participants with higher levels of EPQ trait anxiety, even after controlling for baseline HAM-A scores. A similar interaction with EPQ mood instability was nonsignificant.

CONCLUSION: A potential beneficial effect of escitalopram on neuroticism may be driven by reductions in anxiety.