Washington: High school students or sophomores with mental health issues were more likely to use alcohol, tobacco and marijuana compared to those without symptoms, a study has revealed. The study, published in The American Journal on Addictions, highlights the link between psychiatric symptoms and substance use among teenagers in a middle-income country with high levels of social inequalities. The study results were based on data collected from 4,034 high school students in the 10th to 12th grades at 128 public and private schools in Brazil between four months (September-December). The students, mostly female from public schools, who were aged between 15 to 18, self-reported on alcohol, tobacco, and marijuana substance use patterns. The findings showed that 44 per cent of the students had no psychiatric symptoms, 8 per cent showed some symptoms and 49 per cent reported clinically significant symptoms. Alcohol use was reported at 38 per cent among students with psychiatric symptoms whereas only 2 per cent of students with no mental health issue used alcohol frequently. Tobacco use rates were 9 per cent and 2 per cent among marijuana users, the rate was 7 per cent and 2 per cent for frequent users, suggested the study. Students with a clinically significant score on the behavioural survey were more addicted to alcohol, tobacco and marijuana than those without symptoms. "Studies to determine which specific mental health symptoms are associated with substance use among adolescents in different settings are crucial. Mental health policies should focus on these populations, especially since providing early treatment for psychiatric symptoms may have a direct impact on mental health prevalence and its costs among adults," said Silvia Martins, Associate Professor, Columbia University.