Effects of response requirement and the availability of an alternative reinforcer on cigarette smoking by schizophrenics

Cigarette smoking and other forms of drug abuse are more prevalent among sc hizophrenics than the general population. Despite the clinical importance o f this problem, there has been relatively little experimental study of schi zophrenic drug use. We examined under controlled laboratory conditions the effects of response requirement and the availability of an alternative (mon etary) reinforcer on cigarette smoking by schizophrenics. Subjects were six heavy smokers with diagnoses of schizophrenia or schizoaffective disorder. Before each session, subjects provided carbon monoxide samples indicating recent smoking abstinence. During 3-h sessions, subjects obtained opportuni ties to smoke (2 puffs/opportunity) under a fixed ratio (FR) schedule of re inforcement, which varied across sessions from FR50 to FR6400. In half of t he sessions, subjects also were able to earn a small amount of money ($0.25 /ratio completed) under an FR400 schedule. Increasing the response requirem ent for smoking decreased smoking and increased smoking-maintained respondi ng. The availability of the monetary reinforcer decreased smoking and smoki ng-maintained responding by approximately half. These results are consisten t with those seen previously in community volunteers without major mental i llness studied under the same experimental conditions, suggesting that smok ing by these two populations is controlled, at least in part, by a common s et of determinants.