Less is more: Patient-level meta-analysis reveals paradoxical dose-response effects of a computer-based social anxiety intervention targeting attentional bias.

BACKGROUND: The past decade of research has seen considerable interest in computer-based approaches designed to directly target cognitive mechanisms of anxiety, such as attention bias modification (ABM).
METHODS: By pooling patient-level datasets from randomized controlled trials of ABM that utilized a dot-probe training procedure, we assessed the impact of training "dose" on relevant outcomes among a pooled sample of 693 socially anxious adults.
RESULTS: A paradoxical effect of the number of training trials administered was observed for both posttraining social anxiety symptoms and behavioral attentional bias (AB) toward threat (the target mechanism of ABM). Studies administering a large (>1,280) number of training trials showed no benefit of ABM over control conditions, while those administering fewer training trials showed significant benefit for ABM in reducing social anxiety (P = .02). These moderating effects of dose were not better explained by other examined variables and previously identified moderators, including patient age, training setting (laboratory vs. home), or type of anxiety assessment (clinician vs. self-report).
CONCLUSIONS: Findings inform the optimal dosing for future dot-probe style ABM applications in both research and clinical settings, and suggest several novel avenues for further research.