As well as AA, there are also alternative interventions based on 12-step type programmes, some self-help and some professionally-led. AA and other 12-step approaches are typically based on the assumption that substance dependence is a spiritual and a medical disease. The available experimental studies did not demonstrate the effectiveness of AA or other 12-step approaches in reducing alcohol use and achieving abstinence compared with other treatments, but there were some limitations with these studies. Furthermore, many different interventions were often compared in the same study and too many hypotheses were tested at the same time to identify factors which determine treatment success.