Do Cochrane reviews provide useful information to guide policy and practice? The experience of the Cochrane drugs and alcohol group.

This contribution reviewed the experience of the Cochrane Drugs and Alcohol Group (CDAG) in terms of production of evidence to guide policy and practice. By December 2010, the group had published 55 reviews, with 299 authors involved and 744 primary studies included out of 2114 studies considered for inclusion. 90% of the studies included were randomized controlled trials (RCTs). Considering the 'Implication for practice' section of each review, 31% interventions were classified as to do, 11% as do not do it, 52% to do only in research and for 6% a final judgment was impossible because the reviews included no studies or only one study. These proportions varied according to the type of substance of abuse studied; interventions judged as to do were 42% for alcohol, 32% for opioids, 12% for psychostimulants, 33% for poly drugs, and for prevention. The reviews produced by the CDAG provide evidence on effectiveness of several interventions, and identify areas of uncertainty, where more primary research is needed.