!2 Step approaches such as Narcotics Anonymous (NA) -similar to the older Alcoholics Anonymous (AA)- has a focus on drugs rather than alcohol. AA and NA are the best known of the self-help or mutual-help groups; they are free, voluntarily-attended gatherings characterised by working together on a common problem, self-directed leadership, and the sharing of experiences (Groh et al. 2008). There have been very few studies of the effectiveness of AA, and even fewer studies of NA as an approach distinct from AA. Evidence in relation to AA is summarised here; and as NA is broadly similar to AA, it is assumed that this evidence should apply equally to NA.