Cannabis dependence was measured via the Cannabis Use Disorder Identification Test- Revised (CUDIT-R) (24 (link)), an 8-item self-report measure that assesses problematic cannabis use within the past 6 months. The CUDIT-R has been used in a variety of cannabis subpopulations and has been found to be both valid and reliable (25 (link), 26 (link)). Consistent with the literature, scores of 13 and above were considered indicative of cannabis dependence (24 (link)), with 150 (29.1%) of participants meeting this criteria.
Nicotine dependence was assessed using both the Fagerström Test for Cigarette Dependence (FTCD) (27 (link)) and the e-cigarette Fagerström Test of Cigarette Dependence [e-FTCD; (28 (link))], depending on whether the participant use cigarettes, e-cigarettes, or both. Participants who only used e-cigarettes were directed to complete E-cigarette Fagerström Test of Cigarette Dependence (e-FTCD) (28 (link)). The FTCD is a 6-item self-report measure that assesses a person's level of cigarette dependence. The FTCD is commonly used in nicotine and tobacco research and has good reliability and validity (27 (link)). The e-FTCD is a 6-item adapted version of the FTCD, modified by changing all references of cigarettes to e-cigarettes and all references of smoking to vaping. The e-FTCD has been proven reliable and valid for use with e-cigarette users (28 (link)). Scores of 4 and above were considered indicative of moderate nicotine dependence (29 (link)), with 292 (56.6%) participants meeting this criteria.
Personality traits of the participants were measured via the Substance Use Risk Profile Scale (SURPS) (16 (link)), a 23-item questionnaire that measures 4 distinct personality risk factors based on reinforcement-sensitivity models of substance use: hopelessness/ introversion (HI); anxiety sensitivity (AS); impulsivity (IMP), and sensation seeking (SS). The SURPS has been shown to have adequate psychometric properties (16 (link)).