Cigarette demand and delayed reward discounting in nicotine-dependent individuals with schizophrenia and controls: an initial study.

RATIONALE: The high prevalence of smoking and low cessation rates among individuals with schizophrenia and similar conditions are not well understood. Behavioral economics has been extensively applied to studying addictive behavior and may contribute to understanding smoking in this subpopulation.
OBJECTIVES: This study compared smokers with schizophrenia or schizoaffective disorder (SS) and control smokers (CS) on indices of cigarette demand and delayed reward discounting, a behavioral economic index of impulsivity.
MATERIALS AND METHODS: The SS (n=25) and CS (n=24) groups participated in two sessions approximately 1 week apart. During the first session, delay discounting was assessed using the Monetary Choice Questionnaire. During the second session, participants smoked their usual brand ad libitum through a smoking topography assessment device, after which cigarette demand was assessed using a cigarette purchase task. Primary comparisons were of the hyperbolic discounting function, k, and indices of cigarette demand.
RESULTS: Compared to the CS group, the SS group exhibited significantly higher intensity of demand, and significantly greater consumption and expenditure across the inelastic portion of the demand curve, but no differences were evident on the other demand indices. No differences were evident for delay discounting. The SS group also exhibited heavier smoking topography and two indices of smoking topography were significantly correlated with demand.
CONCLUSIONS: These results provide further evidence of higher incentive value of cigarettes among SS individuals, but not greater impulsivity, as measured by discounting. Considerations include potentially important methodological factors and the role of satiation/withdrawal.