Efficacy of treatments for anxiety disorders: a meta-analysis

To our knowledge, no previous meta-analysis has attempted to compare the efficacy of pharmacological, psychological and combined treatments for the three main anxiety disorders (panic disorder, generalized anxiety disorder and social phobia). Pre–post and treated versus control effect sizes (ES) were calculated for all evaluable randomized-controlled studies (n=234), involving 37 333 patients. Medications were associated with a significantly higher average pre–post ES [Cohen’s d=2.02 (1.90–2.15); 28 051 patients] than psychotherapies [1.22 (1.14–1.30); 6992 patients; P<0.0001]. ES were 2.25 for serotonin–noradrenaline reuptake inhibitors (n=23 study arms), 2.15 for benzodiazepines (n=42), 2.09 for selective serotonin reuptake inhibitors (n=62) and 1.83 for tricyclic antidepressants (n=15). ES for psychotherapies were mindfulness therapies, 1.56 (n=4); relaxation, 1.36 (n=17); individual cognitive behavioural/exposure therapy (CBT), 1.30 (n=93); group CBT, 1.22 (n=18); psychodynamic therapy 1.17 (n=5); therapies without face-to-face contact (e.g. Internet therapies), 1.11 (n=34); eye movement desensitization reprocessing, 1.03 (n=3); and interpersonal therapy 0.78 (n=4). The ES was 2.12 (n=16) for CBT/drug combinations. Exercise had an ES of 1.23 (n=3). For control groups, ES were 1.29 for placebo pills (n=111), 0.83 for psychological placebos (n=16) and 0.20 for waitlists (n=50). In direct comparisons with control groups, all investigated drugs, except for citalopram, opipramol and moclobemide, were significantly more effective than placebo. Individual CBT was more effective than waiting list, psychological placebo and pill placebo. When looking at the average pre–post ES, medications were more effective than psychotherapies. Pre–post ES for psychotherapies did not differ from pill placebos; this finding cannot be explained by heterogeneity, publication bias or allegiance effects. However, the decision on whether to choose psychotherapy, medications or a combination of the two should be left to the patient as drugs may have side effects, interactions and contraindications.