As well as harms, however, recreational drugs have perceived benefits, otherwise they would not be used. There are a variety of historical and emerging beneficial uses of various compounds that are illicit substances; for example cannabis, once used as a sedative and anti-convulsant in the UK and US (Walton, 1938), has recently been explored in its organic form and components as an analgesic, anti-emetic and appetite stimulant. Renewed efforts have also been made to demonstrate the efficacy of illicit drugs as adjuncts to psychotherapy, either as psycholytics or psychedelics, with promising results (see Sessa, 2005 for a review). For example, in two small studies, MDMA has been found to be effective as an adjunct to exposure therapy for post-traumatic stress disorder (PTSD) and therapy-resistant anxiety disorders (Johansen and Krebs, 2009; Mithoefer, 2006; Sessa, 2007). In addiction treatment with single dose of LSD, in the context of alcohol treatment programmes in the 1960s and 1970s, is associated with a decrease in alcohol misuse (Krebs and Johansen, 2012), whilst ketamine has improved rates of abstinence in the treatment of heroin addicts (Krupitsky et al., 2002).
A wide literature has detailed the benefits of recreational drugs to users (e.g. Griffiths et al., 2006, 2008, 2011; Móró and Noreika, 2011; Müller and Schumann, 2011; Tart 1971). However, only two studies to date have compared the potential benefits of illicit drugs to the harms (Carhart-Harris and Nutt, 2010; Morgan et al., 2010b). The latter assessed the perceived acute and long-term benefits of 21 substances in over 1500 drug users whilst the former compared the benefits of four types of substances in 626 users. Users presumably make a complex cost/benefit judgement when taking recreational drugs. Understanding both the harms and benefits of taking drugs for users is important if we are to shape social policy towards harm reduction and minimal state control over personal decision making.