Developing a brief and valid measure of delay discounting

Delay discounting, the rate at which an individual devalues delayed rewards, is a potential neurobehavioural marker of substance use disorder. The Monetary Choice Questionnaire is a commonly used measure of delay discounting. It has good psychometric properties, such as good construct validity, test-retest reliability and limited ceiling effects. A drawback of the questionnaire currently limiting its use in clinical settings is that it is unnecessarily long and repetitive. The questionnaire comprises 27 questions: 9-items within each small ($25‚ÄövÑvÆ$35), medium ($50‚ÄövÑvÆ60) and large ($75‚ÄövÑvÆ$85) delayed reward category. The current investigation aimed to develop a brief, valid and reliable version of the Monetary Choice Questionnaire. An additional aim was to assess if delay discounting was sensitive to acute alcohol intoxication. Of the thirteen brief scales that were developed and tested, a 9-item scale made up of the medium sized delayed rewards replicated the full questionnaire, differentiated people with high and low alcohol harms, according to the alcohol use disorders identification test, and demonstrated good test-retest reliability. The full questionnaire did not differentiate AUDIT groups and was significantly different over the test-retest period. With regards to the secondary aim, acute alcohol intoxication did not significantly affect delay discounting.