Most �addictive behaviour� (craving, anti-social acts, loss of responsibility (i.e. failure to maintain expected roles)), is more complex than a �self-medication� explanation of addiction allows. For instance, most people who become classical pictures of drug addicts have pre-existing social difficulties and often personality characteristics which seem to make them vulnerable to adopting deviant roles (see lectures on social deviance for more on this aspect). Much of the �craving� for drugs has been shown to occur when the drug-taking setting and accoutrements are present, indicating a conditioned expectation of the pharmacological activity (the �high�) related to the physical environment.