Legleye, S., Guignard, R., Richard, J.-B., Kraus, L., Pabst, A., Beck, F.

Properties of the cannabis abuse screening test (CAST) in the general population


International Journal of Methods in Psychiatric Research, 24 (2), 170-183




This paper explores the DSM-IV latent structure of cannabis users (especially its invariance towards gender and age) and assesses the psychometric properties of the Cannabis Abuse Screening Test (CAST) by confrontation with the theoretical diagnoses [dependence and cannabis use disorders (CUD)] and the latent class structure of the DSM-IV. The random sample comprised 550 French cannabis smokers aged 15-62 years interviewed by telephone. DSM-IV diagnoses were assessed with the Munich Composite International Diagnostic Interview. Internal structures of both instruments were assessed using factor analysis and latent class analysis. Optimal CAST cut-offs were determined by sensitivity, specificity and area under the receiver operating curve (AUC). CAST and DSM-IV were unidimensional (Cronbach's á = 0.742 and 0.752, respectively), although a two-factor solution showed a better fit for the CAST. CAST cutoffs for screening CUD and dependence were three (AUC = 0.851) and five (AUC = 0.868), respectively. DSM-IV latent class structure varied only marginally in age and gender. Three classes of cannabis smokers were determined, ordered along a continuum of symptoms: non-symptomatic (61.1%), moderate (32.9%) and severe (6.0%). CAST cutoff scores for screening moderate/severe and severe were, respectively, three (AUC = 0.869) and eight (AUC = 0.952). Results are compared to those obtained in previous CAST studies and discussed in line with the DSM-5.


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