these four instruments is that they are brief and easy to administer. There are also other scales that measure cannabis-related problems, e. g. the Marijuana Screening Inventory (MSI) [16], the Substance Dependence Severity Scale (SDSS) [17], or the Cannabis Problems Questionnaire (CPQ) [18], but these are more extensive and too time-consuming for epidemiological purposes. Thus, MSI and CPQ consist of 31 and 29 items respectively taking about 10 minutes to complete and the SDSS additionally requires interviewer training and clinical experience.
