BEHAVIORAL CONTINGENCIES MODULATE ALPRAZOLAM SELF-ADMINISTRATION BY HUMANS

The effect of monetary contingencies on alprazolam self-administration was evaluated in seven male volunteers living in a residential labora tory. Drug administration occurred prior to an afternoon work session (13.00 h), and at the onset of an evening recreation period (17.30 h), On 'sample' days, participants were administered placebo or alprazola m (0.75 mg), and at the end of the afternoon work session, were told w hether their task performance was 'better' or 'worse' than average, If they received 'better' feedback they earned $55, and if they received 'worse' feedback, they earned $15, On 'choice' days, participants cho se to self-administer either alprazolam or placebo, with feedback occu rring on two of the four choice days, Feedback was not actually linked to performance, but instead was pre-programmed. For one week, alprazo lam administration was always associated with 'better' feedback on sam ple and choice days, and in the other week was associated with 'worse' feedback, When no feedback was delivered, alprazolam was self-adminis tered equally often in the afternoon (57%) and evening (71%), When fee dback was delivered, it significantly influenced the choice to self-ad minister alprazolam in the afternoon. 'Better than average' feedback r esulted in alprazolam self-administration 57% of the time, but alprazo lam self-administration decreased to 14% when it was associated with ' worse than average' feedback and reduced earnings, A similar pattern o f effects has been reported for d-amphetamine. Thus, the self-administ ration of either a stimulant or a minor tranquilizer is significantly reduced when it is associated with a consequent loss of an alternative reinforcer, in this case money.