Pathological gamblers discount probabilistic rewards less steeply than matched controls

Nineteen treatment-seeking men meeting Diagnostic and Statistical Manual for Mental Disorders (4th ed.) criteria for pathological gambling and 19 demographically matched controls participated. Participants provided demographic information, information about their recent drug use and gambling activities, and biological samples (to confirm drug abstinence). They also completed the Eysenck Personality Questionnaire, the South Oaks Gambling Screen (SOGS), and 2 questionnaires designed to separately quantify probability and delay discounting. Pathological gamblers discounted probabilistic rewards significantly less steeply than matched controls. A significant correlation revealed that more shallow probability discounting was associated with higher SOGS scores. Across groups, there was no significant difference in delay discounting, although this difference approached significance when education and ethnicity were included as covariates. These findings, collected for the 1st time with pathological gamblers, are consistent with previous reports that problem-gambling college students discount probabilistic rewards less steeply than controls. The nature of the relation between probability discounting and severity of problem gambling is deserving of further study.