August 2, 2016 -- Researchers at Columbia University's Mailman School of Public Health with collaborators at the Federal University of Sao Paulo studied the relationship between psychiatric symptoms and patterns of substance use among high school students in Brazil and found that respondents with clinically significant scores on a behavioral screening questionnaire were more likely to use alcohol, tobacco, and marijuana in the past month compared to those without symptoms. The study is among the first to highlight the link between psychiatric symptoms and substance use among teenagers in a middle-income country with high levels of social inequalities. The paper is published online in The American Journal on Addictions.

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 São Paulo between September 2013 and December 2013. The students, who were between the ages of 15 and 18, self-reported on alcohol, tobacco, and marijuana substance use patterns in the prior month. Most of the students were female and from public schools. The researchers controlled for gender and socio-economic status.

The findings showed that 44 percent of the students had no psychiatric symptoms, 8 percent showed some symptoms and 49 percent reported clinically significant symptoms. Past-month alcohol use was reported at 38 percent; only 2 percent of students used alcohol frequently. Tobacco use rates were 9 percent and 2 percent, for past-month and frequent use, respectively. Among marijuana users in the past month, the rate was 7 percent, and 2 percent for frequent users.

Respondents with a clinically significant score on the behavioral survey, the Strengths and Difficulties Questionnaire for young children and adolescents, or SDQ, were more likely to be past-month alcohol users, past-month tobacco users, and past-month marijuana users as compared to those without symptoms. Substance use varied by psychiatric symptoms; researchers looked at emotional symptoms, conduct problems, hyperactivity, peer relationships, and positive social behavior.

"Studies to determine which specific mental health symptoms are associated with substance use among adolescents in different settings are crucial," noted Silvia Martins, MD, PhD, associate professor of Epidemiology. "In developing countries such as Brazil where a wide gap of social inequalities is observed, this is particularly important. 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."

Source: Columbia University's Mailman School of Public Health