Studies that evaluated the psychometric properties concerning the reliability or validity of one of the following four scales were eligible for inclusion: Cannabis Abuse Screening Test (CAST); Severity of Dependence Scale (SDS); Cannabis Use Disorders Identification Test (CUDIT); and Problematic Use of Marijuana (PUM). Studies that used these questionnaires to assess the validity of another instrument were excluded. Included studies assessed adults and adolescents. Studies were conducted in Australia, New Zealand, Brazil and Europe. Studies assessed general population and specific-user samples that included long-term cannabis users, patients with schizophrenia, cocaine users and out-patients with alcohol dependence. Sampling involved probabilistic populations samples, convenience samples, non-probabilistic school samples and snowball samples. Scales were administered as questionnaires and/or during interviews, some of which were conducted by telephone. Most studies assessed dependence, but some assessed social and health problems and motivation. Reference standards used in included studies were DSM-IV dependence, any DSM-IV or ICD-10 diagnosis, Problem Oriented Screening Instrument for Teenagers (POSIT) and cannabis use.
The authors state neither how papers were selected for the review nor how many reviewers performed the selection.