When it comes to the global health agenda, deadly diseases such as malaria, HIV, heart disease and cancer claim much of the attention. Public health organizations focus much less on mental health—to the detriment of millions.

Depression ranks third on the list of the world's top chronic diseases, according to the World Health Organization, and rates continue to rise. Depression will likely overtake heart disease and cancer to become the single most common chronic disease by 2030. Yet according to a 2004 survey by the WHO, between 76 percent and 85 percent of people with severe mental disorders in low- and middle-income countries receive no treatment (Journal of the American Medical Association, 2004). Even more disturbing: Worldwide, suicide claims at least a million lives each year, according to WHO figures; that toll is expected to climb to 1.5 million by 2020.

Despite the grim statistics, Elizabeth Carll, PhD, chair of the United Nations Non-Governmental Organizations (NGO) Committee on Mental Health, sees signs of positive change. The committee lobbies the 193 nations of the U.N. General Assembly and international agencies to include mental health in the global health agenda, and their advocacy is paying off. In September, at a summit on non-communicable diseases, the U.N. General Assembly adopted a declaration that included mental health problems as risk factors for non-communicable diseases.

The declaration was a milestone for two reasons, Carll says. First, it finally recognizes that mental and physical health are two sides of the same chronic-disease coin—and that both should be addressed in disease-control efforts. Second, the declaration acknowledges that primary care is the best way to deal with a global epidemic of chronic illness, and that mental health care should be integrated into primary care.

There are other indications that the global mental health movement is gaining momentum. Last summer, a consortium of mental health professionals published a paper identifying the "grand challenges in global mental health" (Nature, 2011). The group identified 25 goals for identifying risk factors, improving treatment and access to care, raising awareness and transforming health systems to address mental health.

And in January, a group of experts called publicly for a U.N. General Assembly special session on mental, neurological and substance abuse disorders (PLoS Medicine, 2012). Such disorders should be "a global development priority," the authors write.

There's a long way to go, but these advancements offer reason for hope. "We have to be vigilant to make sure mental health continues to be recognized," Carll says.

—K. Weir