BackgroundThe use of reliable and valid self-report questionnaires to identify drug use disorders (DUD) is a strategy that has shown usefulness for screening. One of the instruments more used for detection is the Drug Abuse Screening Test (DAST). The psychometric properties in the 20-and 10-item versions have been evaluated in other countries but in Mexico the psychometric and diagnostic properties of both versions are yet to be evaluated.

Co-occurring disorders are highly prevalent in community-based residential centers in Mexico and are associated with significantly increased probability of other health risks. This highlights the need to develop care standards for this population and the importance of clinical research in these settings.

Objective: To identify symptom-based subgroups within a sample of patients with co-occurring disorders (CODs) and to analyze intersubgroup differences in mental health services utilization. Methods: Two hundred and fifteen patients with COD from an addiction clinic completed the Symptom Checklist 90-Revised. Subgroups were determined using latent class profile analysis. Services utilization data were collected from electronic records during a 3-year span. Results:The five-class model obtained the best fit (Bayesian information criteria [BIC] = 3,546.95; adjusted BIC = 3,363.14; bootstrapped likelihood ratio test p o 0.0001). Differences between classes were quantitative, and groups were labeled according to severity: mild (26%), mild-moderate (28.8%), moderate (18.6%), moderate-severe (17.2%), and severe (9.3%). A significant time by class interaction was obtained (chi-square [w Conclusion:The classes with more symptom severity (moderate-severe and severe) displayed lower utilization of services across time when compared to participants belonging to less severe groups. However, as pairwise differences in treatment utilization between classes were not significant between every subgroup, future studies should determine whether subgroup membership predicts other treatment outcomes.

Substance use related problems, clinical features, and addiction severity reported by treatment seekers are important characteristics to take into account when planning treatment as they facilitate tailoring treatment to meet patients' needs.

Although the FTND showed an adequate construct validity, the results suggest that its convergent and predictive validity is limited; therefore, it might not be suitable for the Mexican population. More studies in other populations are needed to establish the generalizability of these findings.