Objective: To detect latent patterns of drug-related problems and their predictors among adolescents. Methods: A three-wave randomized controlled trial was conducted among 6,391 7th and 8th graders (51.02% girls) at 72 public schools in six Brazilian cities to evaluate the #Tamojunto school-based drug prevention program. Patterns of drug use and behavior problems were identified through latent class analysis, and logistic regression analyses were used to detect predictors of high-risk and low-risk groups. Results: Two groups were found that best explained the patterns of drug use and problem behaviors: high drug use/high problems and low drug use/low problems, representing 36.7 and 63.3% of the sample, respectively. No program effect was a determinant of the risk of belonging to these groups. Any reported problem behavior in the year preceding baseline assessment increased the likelihood of belonging to the high-risk group at the 21-month follow-up by 16 times. Alcohol use at baseline and female gender increased the likelihood of belonging to the high-risk group by 70%. Conclusion: Previous behavior problems and alcohol use were the strongest predictors of higher risk, suggesting that effective earlier interventions and early screening for alcohol use and behavioral problems are needed at schools, particularly for girls. Clinical trial registration: Registro Brasileiro de Ensaios Clínicos (REBEC), RBR-4mnv5g

Objectives: To study the prevalence of psychiatric disorders in adolescents with and without type 1 diabetes, the factors associated with its presence, and to test the reliability of a screening tool for use in clinical settings. Methods: Eighty-one adolescents were enrolled in this case-control study, including 36 diabetic participants and 45 controls. Clinical and sociodemographic data were collected and psychiatric symptoms and diagnoses were obtained from adolescents and their parents using a screening tool (Strengths & Difficulties Questionnaire) and a semi-structured interview (Development and Well-Being Assessment). Results: Psychiatric disorders were identified in 22.2% of the sample (30.56% among diabetic adolescents vs. 15.56% of controls: OR = 2.39, 95%CI 0.82-6.99; p = 0.11). Overweight (body mass index percentile ≥ 85) was the only factor associated with psychiatric disorder (OR = 3.07; 95%CI 1.03-9.14; p = 0.04). Compared to the semi-structured interview, the screening instrument showed 80% sensitivity, 96% specificity, 88.9% positive predictive value and 92.3% negative predictive value for the presence of psychiatric diagnoses in adolescents. Conclusion: Psychiatric morbidity was high in this sample of adolescents, especially among those with diabetes. Routine use of the Strengths and Difficulties Questionnaire can help with early detection of psychiatric disorders in this at-risk group.