As part of the screening questionnaire, a set of questions were asked of all participants regarding the individual's substance use. The questions were adapted from the DIGS 24, and other validated instruments 27,28. Do you often have more than 4 drinks in one day?Over your lifetime, have you smoked more than 100 cigarettes?Have you ever had a period of one month or more when you smoked cigarettes every day?Have you ever smoked marijuana more than 21 times in a single year?Have you ever used recreational (street) drugs [other than marijuana] or prescription drugs more than 10 times to feel good or get high?
