The relative efficacy and efficiency of single- and multi-session exposure therapies for specific phobia: A meta-analysis.

Exposure therapy is the preferred treatment for specific phobia (SP), with evidence supporting its efficacy whether delivered over multiple sessions or as a single session, such as One-Session Treatment. In this meta-analysis, we compared the efficiency and effectiveness of single- and multi-session exposure for SP. PsycINFO, Embase, MEDLINE, and Cochrane were systematically searched for peer-reviewed articles reporting the effects of multi-session (k = 30) and/or single-session (k = 55) in vivo exposure on SP symptoms in clinical populations (n = 1758 participants). A random-effects model was used to synthesise and compare the pre-post treatment effects (Hedges' g) on approach behaviour and self-reported SP symptoms. Mean total treatment time was significantly longer for multi-session exposure than for single-session. There were no significant differences in the pooled effect sizes of single-session and multi-session exposure at post-treatment and follow-up assessments; effect sizes were large for all outcomes. Phobia subtype significantly moderated the effect size for both treatment approaches, although the direction of association differed according to the outcome measures. Results suggest no evidence for differences in the effectiveness of single- and multi-session exposure, but single-session is more time efficient. These outcomes suggest that policies to facilitate access to single-session exposure would be beneficial.