Screening of cannabis-related problems among youth: the CPQ-A-S and CAST questionnaires

Information was obtained on sociodemographics, frequency of substance use, psychopathological symptoms and cannabis-use problems, and the CPQ-A-S and CAST were applied, as well as an infrequency scale for discarding responses made randomly. The sample was made up of 144 young people aged 16 to 20 that had used cannabis in the last month, of which 71.5% were boys. Mean age of the sample was 17.38 years (SD = 1.16).The results show that from the psychometric point of view both the CAST and the CPQ-A-S are good screening instruments.The CAST is shorter and presents slightly better internal consistency than the CPQ-A-S. Both instruments show high sensitivity and specificity in the detection of young people dependent on cannabis according to the DSM IV-TR criteria. The CPQ-A-S appears to show greater capacity for detecting psychopathological distress associated with use. Both questionnaires yield significant odds ratios as predictors of frequent cannabis use and of the DSM IV-TR abuse and dependence criteria. In general, the CPQ-A-S emerges as a better predictor than the CAST.Prevalence of cannabis use among adolescents is very high. In Europe the most recent data [1]on prevalence of use in those aged 15 and 16, according to the European Monitoring Centre for Drugs and Drug Addiction, indicate lifetime prevalence of between 4% and 45%, annual prevalence of 2% to 35% and monthly prevalence of 1% to 20%, depending on the country. In the most highly populated countries (Germany, France, United Kingdom, Spain, Italy), more than 20% report having used cannabis at some time in their life, more than 15% in the last year, and over 7% in the last month [1]. As in most European countries, figures have stabilized in Spain since the beginning of the 2000s [2]. However, Spanish prevalence of cannabis use in lifetime (37%), last year (30%) and last month (20%) is among the highest [1]. Furthermore, age at onset of cannabis use among Spanish adolescents has decreased from 15.1 years in