Randomized Controlled Trial of Mindfulness Meditation for Generalized Anxiety Disorder: Effects on Anxiety and Stress Reactivity

Objective: Mindfulness meditation has met increasing interest as a therapeutic strategy for anxiety disorders, but prior studies have been limited by methodological concerns, including a lack of an active comparison group. This is the first randomized, controlled trial comparing the manualized Mindfulness-Based Stress Reduction (MBSR) program with an active control for Generalized Anxiety Disorder, a disorder characterized by chronic worry and physiological hyperarousal symptoms.

Method: Ninety-three individuals with DSM-IV-diagnosed GAD were randomized to an 8-week group intervention with MBSR or to an attention control, Stress Management Education (SME) between 2009 and 2011. Anxiety symptoms were measured with the Hamilton Anxiety Scale (HAM-A, primary outcome measure), the Clinical Global Impression of Severity and Improvement (CGI-S and CGI-I), and the Beck Anxiety Inventory (BAI). Stress reactivity was assessed by comparing anxiety and distress during pre- and post-treatment Trier Social Stress Tests (TSST).

Results: A modified intent-to-treat analysis including participants who completed at least one session of MBSR (N=48) or SME (N=41) showed that both interventions led to significant reductions in HAM-A scores at endpoint, but did not significantly differ. MBSR, however, was associated with a significantly greater reduction in anxiety as measured by the CGI-S, the CGI-I, and the BAI (all Ps<0.05). MBSR was also associated with greater reductions than SME in anxiety and distress ratings in response to the TSST stress challenge (P<0.05), and a greater increase in positive self-statements (P=0.004).

Conclusions: These results suggest that MBSR may have a beneficial effect on anxiety symptoms in GAD, and may also improve stress reactivity and coping as measured in a laboratory stress challenge.