Global map of depression

WHO report on depression brings together population studies in 18 countries and shows a relationship between the disorder and social conditions.

By Fábio de Castro

Agência FAPESP – Major Depressive Episode, or MDE, is a major issue for public health around the globe and is connected to the social conditions in some of the countries evaluated in the study. This is the main conclusion of a study that brought together epidemiological data from 18 countries including Brazil. The results were presented in the article Epidemiologia transnacional do MDE [Transnational Epidemiology of MDE], published in BMC Medicine open access magazine.

Depression is a sickness characterized by a set of psychological and physical symptoms associated with high rates of medical comorbidities, disability and premature death. The countries studied were divided into two groups: high income (Belgium, France, Germany, Israel, Italy, Japan, Holland, New Zealand, Spain and the United States); and low and medium income (Brazil – with data exclusively from São Paulo –, Colombia, India, China, Lebanon, Mexico, South Africa and Ukraine).
 
According to the report, in the ten high income countries studied, 14.6% of all people on average had suffered from MDE. The rate was 5.5% for the 12 months previous to the study. In the eight low or medium income countries studied, 11.1% of the population had had an episode at some point in their lives and 5.9% in the 12 months previous to the study. The highest rate in the last 12 months was recorded in Brazil, with 10.4%. The lowest was in Japan, with 2.2%.

The project is part of the World Mental Health Survey, a World Health Organization initiative that integrates and analyses epidemiological studies on substance abuse and mental and behavioral disorders. Ronald Kessler of Harvard University is global coordinator of the study.

The São Paulo Megacity Mental Health Survey, which was the source of Brazilian data for the WHO study, was financed by FAPESP as the Thematic Project  "An epidemiological study of psychiatric disorders in the São Paulo Metropolitan Region: prevalence, risk factors, and social and economical burden”, and completed in 2009.

The article was written by Laura Helena Andrade, professor at Universidade de São Paulo Medical School’s  Department and Institute of Psychiatry (IP-FM-USP), and Maria Carmen Viana, professor at the Universidade Federal do Espírito Santo’s Department of Social Medicine. 

Andrade conducted the Thematic Project together with Viana, who was a post-doctoral FAPESP fellow between 2008 and 2009 at the Nucleus of Psychiatric Epidemiology at IP-FM-USP, coordinated by Andrade.

According to Viana, the São Paulo Megacity Mental Health Survey is a cross-sectional population-based epidemiological study that evaluated 5,037 residents of the São Paulo metropolitan region in their homes. The same diagnostic instrument was used as the basis for all the interviews. Around 30 nations are participating in the World Mental Health Survey today with similar studies. 

“The same methodology was applied in all countries. Only data on major depression was included in the international article, but our study looked at a number of other mental disorders including anxiety (panic, specific phobias, social phobia and obsessive compulsive disorder) and mood disorders such as bipolarity, dysthymia as well as major depression,” Viana told Agência FAPESP.

Results were also recently published on bipolarity, suicide and smoking. “In the São Paulo Megacity study, we estimated that 44.8% of the population has already experienced some sort of mental disturbance at least once in their lives. In the 12 months previous to the study, the rate was 26.9%,” she said.

According to the transnational study, major depression is one of the greatest causes of disability the world over. “Epidemiological data aren’t available in many countries, however, especially in low income and medium income countries like Brazil. This is why it’s so important to have this type of population-based study,” Viana affirmed.

The Brazilian public health system leaves something to be desired in terms of assistance for mental health, days Viana. “I believe that data like these should be an alert and a foundation for public mental health treatment and prevention policy. These policies must be drawn and implemented according to the needs we find within our population,” affirmed Viana.

Greater prevalence in women

The study showed that in high income countries, the average age for onset of episodes of major depression was 25.7 years as compared to 24 years in low income countries. Functional disability was shown to be associated with recent manifestations of MDE.

The study also revealed that prevalence is twice as high in women as it is in men. In high income countries, youth is associated with a higher rate of depression in the 12 months previous to the interview. On the other hand, in many low income countries, the oldest people involved in the studies showed a greater probability of having depressive episodes.

Separation from a partner was the factor that most correlated with MDE in high income countries. In lower and medium income countries, the most important factors were divorce and widowhood.

The report recommended that future studies investigate the combination of demographic risk factors associated with MDE in the countries included in the World Mental Health Survey Initiative.

The article Cross-national epidemiology of DSM-IV major depressive episode (doi:10.1186/1741-7015-9-90), by  Ronald Kessler and others can be accessed freely in BMC Medicine at www.biomedcentral.com/1741-7015/9/90/abstract.