Greater São Paulo has a high prevalence of mental disorders

An international study indicates that 30% of the Greater Metropolitan Region’s inhabitants have mental disorders, the highest recorded prevalence of 24 studied countries.

By Fábio de Castro

Agência FAPESP – Almost 30% of the inhabitants of the São Paulo Metropolitan Region have mental disorders, according to a study that combined epidemiological data from 24 countries. The prevalence of mental disorders in São Paulo was the highest of all of the areas studied.

The study is part of the Global Study on Mental Health, an initiative of the World Health Organization, which integrates and analyzes epidemiological research on substance abuse and mental and behavioral disturbances. Ronald Kessler of Harvard University is the global coordinator of the study.

In an article published in PLoS One on February 14, the authors presented the results of the São Paulo Megacity Mental Health Survey, which is part of the international report but was created solely from data on Brazil, where the study was restricted to Greater São Paulo.  

The study was conducted under the auspices of the Thematic Project financed by FAPESP and was finalized in 2009. Among the authors of the article are Laura Helena Andrade, professor at the Department and Institute of Psychiatry at Universidade de São Paulo’s Medical School (FM-USP), and Maria Carmen Viana, professor at Universidade Federal do Espírito Santo’s Department of Social Medicine.

Andrade conducted the Thematic Project in partnership with Viana, who received a FAPESP Post-Doctoral Scholarship from 2008 to 2009 at the Psychiatric Epidemiology Center at IP-FM-USP, which is coordinated by Andrade.

A population-based epidemiological study, the São Paulo Megacity Mental Health Survey evaluated a representative sample of residents in the São Paulo Metropolitan Region (5,037 people in their homes) through interviews utilizing the diagnostic instrument. The questionnaires included social data.

According to the study, 29.6% of the individuals in the São Paulo Metropolitan Region presented mental disorders in the 12 months prior to the interview. Anxiety disorders were the most common, affecting 19.9% of those interviewed. These were followed by behavioral disorders (11%), impulse control disorders (4.3%) and substance abuse (3.6%).

“Two groups proved especially vulnerable: women who live in areas considered impoverished are highly vulnerable to mood disorders, while migrant men who live in precarious regions show high vulnerability to anxiety disorders,” Andrade explained in an interview with Agência FAPESP.

The prevalence of mental disorders, almost 30%, is the highest among the countries included in the study. The United States came in second, with a prevalence of slightly less than 25%. The reason for the high prevalence, according to the researcher, is the intersection of two variables included in the study: high urbanization and social deprivation.

In relation to other regions studied, the São Paulo Metropolitan Region also had the highest proportion of serious mental disorders (10%), well above the estimated value in the 14 countries evaluated. After São Paulo, the countries with the highest percentage of serious cases were the United States (5.7%) and New Zealand (4.7%).

“There is data in the literature showing that these mental disorders have a high prevalence in urban areas. For this reason, we observed the effect of urbanicity on exposure, that is, people that live the majority of their life in an urban region. We took into consideration the variable of social deprivation, the population’s age structure, census sectors, the head of the household’s educational level, migration, and exposure to violent traumatic events,” Andrade said.

Exposure to crime was associated with four types of mental disorders, according to Andrade. High urbanicity is particularly associated with control and impulse disorders. Social deprivation also has an impact on substance abuse disorders and the severity of the diseases.

“People who live in precarious areas experience more serious conditions and have tendencies toward substance abuse. Those that had more exposure to urban life have more control and impulse disorders – particularly intermittent explosive disorders in traffic, for example,” she notes.

By including several variables, the researchers identified highly vulnerable groups. Women who live in impoverished areas are likely to suffer from mood disorders, and migrant workers who live in middle- to high-deprivation areas are likely to have more anxiety disorders. People with low educational levels have high levels of anxiety disorders and substance abuse.

“One of the differentials of this study is that we included incapacitation measures in the interviews as a means of evaluating the seriousness of diseases. We concluded that among the people diagnosed with mental disorders, a third corresponds to serious cases, a third to moderate and a third to lighter cases. The people with moderate and serious disorders suffer from some type of incapacitation,” explains Andrade.

The article Mental Disorders in Megacities: Findings from the São Paulo Megacity Mental Health Survey, Brazil, by Laura Andrade and others, can be read at www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031879.