Half of all adults with anxiety or depression in São Paulo suffer from chronic pain

Study by researchers at University of São Paulo Medical School’s Psychiatry Institute warns that health system should take comorbidity into account.

By Maria Fernanda Ziegler  |  Agência FAPESP – There is a strong two-way correlation between anxiety or depression and certain chronic physical conditions. Researchers at the Psychiatry Institute (IPq) of the University of São Paulo’s Medical School (FM-USP), in Brazil, measured this correlation in adults who live in the São Paulo Metropolitan Area, and their findings were alarming.

Chronic pain was the most common physical complaint detected among individuals with mood disorders such as depression and bipolar disorder. Chronic pain occurred in 50% of people with mood disorders. The next most common comorbidities were respiratory disease (33%), cardiovascular disease (10%), arthritis (9%) and diabetes (7%).

Anxiety disorders were also frequently associated with chronic pain (45%) and respiratory disease (30%) as well as arthritis (11%) and cardiovascular disease (11%). Hypertension correlated strongly with both mood and anxiety disorders (23%). Overall, the survey found that individuals with mood or anxiety disorders were twice as likely to have chronic diseases.

The study is described in an article in the Journal of Affective Disorders and was carried out as part of the São Paulo Megacity Mental Health Survey, completed in 2009 in connection with the FAPESP-funded Thematic Project “Epidemiological study of psychiatric disorders in the São Paulo Metropolitan Region: prevalence, risk factors, and social and economic burden”. The survey involved interviews with 5,037 inhabitants of the São Paulo Metropolitan Area aged 18 or older (read more about the São Paulo Megacity Mental Health Survey at agencia.fapesp.br/15329). 

The survey findings point to a need to devote more attention to this kind of comorbidity. “We already knew there was a strong association between mental illness and these physical conditions. The problem is the very high prevalence of anxiety and depression in São Paulo because of stress. These numbers force us to insist on the importance of passing on information to front-line physicians working in primary care. It’s crucial to recognize the comorbidity between anxiety or depression and various chronic diseases in addition to chronic pain,” said Laura Helena Andrade, who heads IPq’s Center for Psychiatric Epidemiology and was one of the authors of the study.

A simple calculation is sufficient to understand the magnitude of the problem. Of the roughly 11 million adult inhabitants of the São Paulo Metropolitan Area, 1.1 million, or 10%, had suffered from depression in the previous 12 months, while another 2.2 million had suffered from anxiety disorders and 990,000 also complained of chronic pain. According to the calculation, over 2 million people were living with depression or anxiety associated with chronic pain in Greater São Paulo at the time of the survey.

The authors of the study stress that in this setting, there is a clear need to make the diagnosis and treatment of mental illness priorities for the health system. Andrade also warned that the prevalence of these diseases is set to increase in the years ahead.

“Research on health problems in major cities shows an increase in the prevalence of depression and anxiety, very probably linked to changes in lifestyle in these cities,” she said. “So it’s reasonable to foresee an increase in the entire package: not just depression and anxiety but also other disorders, such as heart attack, stroke, diabetes, hypertension and pain.”

Puzzle

Previous studies had consistently evidenced the association between chronic diseases and mood or anxiety disorders, but the intensity of the link between chronic pain and anxiety or depression is a puzzle, as the physiopathological mechanisms of chronic pain are not well understood. 

This comorbidity may be a reflection of the behavioral limitations due to physical disorders that restrict patients’ ability to undertake gratifying activities.

According to Andrade, just as immune system cells are activated when the organism is attacked by a pathogen, psychological stress in an environmental situation such as living in a mega-city like São Paulo may eventually activate the inflammatory system.

“An increase in inflammation, damage to the endothelium – the cells that form the inner lining of blood vessels – and oxidative stress are some of the phenomena that may help explain this comorbidity,” Andrade said. “It’s imperative to treat symptoms of depression and anxiety aggressively in patients with chronic medical conditions. If they are satisfactorily addressed, this could be accompanied by an improvement in all other symptoms and a significant reduction in the risk of complications and even death.”

However, she added that more research, focusing on the interaction between depression or anxiety and chronic physical conditions, is required to elucidate the mechanisms that give rise to these diseases.

The article “Dual burden of chronic physical diseases and anxiety/mood disorders among São Paulo Megacity Mental Health Survey Sample, Brazil,” by Melanie S. Askari, Laura Helena Andrade, Alexandre Chiavegatto Filho, Camila Magalhães Silveira, Erica Siu, Yuan-Pang Wang, Maria Carmen Viana and Silvia S. Martins, can be retrieved from sciencedirect.com/science/article/pii/S0165032717308364.