Objectives: This exploratory analysis examined the putative
antidepressant effect of Matricaria chamomilla L. (
chamomile) extract in subjects with generalized
anxiety disorder (GAD) with or without comorbid depression. It was hypothesized that
chamomile extract would demonstrate similar
anxiolytic activity in both subgroups, but superior
antidepressant activity in GAD subjects with comorbid depression. Design: As part of a randomized double-blind placebo-controlled trial of
chamomile extract for
relapse prevention of GAD, 179 subjects received initial
therapy with open-label
chamomile extract 1500 mg daily for 8 weeks. Linear mixed-effect models were used to identify clinically meaningful changes in anxiety and depression symptoms between diagnostic subgroups. Settings/Location: The study took place at the University of Pennsylvania in Philadelphia, PA. Subjects: Subjects were ≥18 years old with a primary DSM IV-TR diagnosis of GAD. They were subcategorized into two diagnostic groups: GAD without comorbid depression (n = 100) and GAD with comorbid depression (n = 79). Interventions: Open-label
chamomile extract 1500 mg was given daily for 8 weeks. Outcome measures: Generalized
anxiety disorder (GAD-7), Hamilton rating scale for anxiety, Beck anxiety inventory, Hamilton rating scale for depression (HRSD), the six-item core HRSD (items 1, 2, 3, 7, 8, and 13), and the Beck depression inventory (BDI). Results: The authors observed similar
anxiolytic effects over time in both diagnostic subgroups. However, there was a greater reduction in HRSD core symptom scores (p < 0.023), and a trend level reduction in HRSD total scores (p = 0.14) and in BPI total scores (p = 0.060) in subjects with comorbid depression. Conclusions: M. chamomilla L. may produce clinically meaningful
antidepressant effects in addition to its
anxiolytic activity in subjects with GAD and comorbid depression. Future controlled trials in subjects with primary
major depressive disorder are needed to validate this preliminary observation.