What’s in a Trial? On the Importance of Distinguishing Between Experimental Lab Studies and Randomized Controlled Trials: The Case of Cognitive Bias Modification and Alcohol Use Disorders

OBJECTIVE: Recently, the National Institutes of Health (NIH) redefined clinical trials to include any study involving behavioral or biomedical interventions. In line with a general framework from experimental medicine, we argue that it is crucial to distinguish between experimental laboratory studies aimed at revealing psychological mechanisms underlying behavior and randomized controlled trials (RCTs) in clinical samples aimed at testing the efficacy of an intervention. METHOD: As an illustration, we reviewed the current state of the evidence on the efficacy of cognitive bias modification (CBM) interventions in alcohol use disorders. RESULTS: A recent meta-analysis "cast serious doubts on the clinical utility of CBM interventions for addiction." That analysis combined experimental laboratory studies and RCTs. We demonstrated that, when studies are differentiated regarding study type (experimental laboratory study or RCT), mode of delivery (controlled experiment or Internet), and population (healthy volunteers or patients), the following effects are found: (a) short-lived effects of CBM on drinking behavior in experimental laboratory studies in students, but only when the bias is successfully manipulated; (b) small but robust effects of CBM on treatment outcome when administered as an adjunct to established treatments in clinical settings in RCTs with alcohol-dependent patients; and (c) nonspecific effects (reduced drinking irrespective of condition) in RCTs of CBM administered online to problem drinkers. CONCLUSIONS: We discuss how CBM might be improved when it is better integrated into regular treatment, especially cognitive behavioral therapy, and we conclude that disregarding the difference between experimental laboratory studies and RCTs can lead to invalid conclusions.