Distressing data

Reliable data on suicide across Asia were once maddeningly scarce. In Thailand until 2003, there was no requirement that the reported cause of death be medically validated—a flaw that rendered the country’s suicide data inaccurate. In India, suicide is a crime, which means it often goes unreported. But the Thai government now has a more accurate reporting system for mortality figures, while Indian researchers are benefiting from the Million Death Study, an effort to catalog causes of death for 1 million Indians in a 16-year survey relying on interviews with family members (Science, 15 June, p. 1372). The study has already produced a disturbing revelation about reported suicide rates. “When we compare our data with police reports, you find undercounts of at least 25% in men and 36% in women,” says Jha, the study’s lead investigator.

New insights from China are particularly instructive. Because suicide carries a stigma, the Chinese government withheld data on the topic until the late 1980s. When information finally came out, it quickly became clear that the country had a serious problem. In 1990, for example, the World Bank’s Global Burden of Disease Study estimated there were 343,000 suicides in China—or 30 per 100,000 people. The U.S. rate for the same year was 12 per 100,000.

But other reports gave different figures, prompting a debate on sources. WHO’s extrapolated total was based on data that China had reported from stations covering only 10% of the population, skewed toward urban residents. As researchers focused on the problem, they arrived at more reliable figures—but also unearthed more mysteries. In an analysis in The Lancet in 2002, a group led by Michael Phillips of Shanghai Mental Health Center and Emory University School of Medicine in Atlanta estimated that from 1995 to 1999, Chinese women killed themselves more frequently than men—by a ratio of 5 to 4. “There was originally disbelief about the very different gender ratio in China,” Phillips says, although later it was accepted.

Today, the suicide sex ratio in China is roughly 1 to 1, still a significant departure from the overall U.S. male-to-female ratio of 4 to 1. In India, the male-to-female suicide ratio is 1.5 to 1, although in the 15 to 29 age group it is close to equal. And yet, WHO estimates the global sex ratio at three men to one woman. (With colleague Cheng Hui, Phillips recently used Chinese and Indian figures to lower that estimate to 1.67 to 1.) Among young adults in India, suicide is second only to maternal mortality as a cause of death for women, according to the Million Death Survey.

In both China and India, cases like Mrs. Y’s involving no apparent mental illness are common. In India, suicide is most prevalent among teenagers and young adults—the cohort that is entering the workforce, marrying, and facing new life stresses. This contrasts with the Western pattern of high suicide rates among the middle-aged, suggesting that although “there might well be some underlying psychiatric conditions, the main drivers of [suicide in India] are probably chiefly social conditions,” Jha says. While cautioning that detailed psychological autopsies are still needed in India, he says, “it’s a reasonable assumption that many of these young folks are not mentally ill.”

Convincing researchers outside Asia may prove an uphill battle. Matthew Miller, a suicide researcher at the Harvard Injury Control Research Center in Boston, says that mental illness may be underdiagnosed in Asia for reasons that aren’t fully understood. That could throw off correlation studies. Phillips, who has worked in China for over 20 years, agrees that underdiagnosis is a problem, and that “many Western researchers still believe that we are just missing cases.” But he rejects that explanation. Even accounting for underdiagnosis, he says, the finding of a lower rate of mental illness among suicide victims has held up in multiple studies. Many Chinese suicide victims, he adds, are “most certainly severely distressed, but they don’t meet the criteria of a formal mental illness.”

Lethal weapons

Assuming that suicide risk is shaped by different factors in Asia, researchers are striving to uncover the roots. One clue may lie in the high proportion of unplanned Chinese suicides. In a 2002 survey of 306 Chinese patients who had been hospitalized for at least 6 hours following a suicide attempt, Phillips and colleagues found that 35% had contemplated suicide for less than 10 minutes—and 54% for less than 2 hours. Impulsiveness among suicide victims in Asia “tends to be higher than in the West,” says Paul Yip, director of the Hong Kong Jockey Club Centre for Suicide Research and Prevention at the University of Hong Kong and one of the authors of a recent WHO report on suicide in Asia. Although impulsive personality traits are sometimes linked to illnesses like bipolar disorder, studies in China have not uncovered full-fledged personality disorders in impulsive suicide victims.

In a tragic twist, impulsive victims in Asia tend to favor highly fatal methods. After interviewing family members and friends of 505 Chinese suicide victims, Kenneth Conner, a psychiatric researcher at the University of Rochester Medical Center in New York, and colleagues reported in 2005 that those who had ingested pesticides were more likely to have acted rashly than were those who used other methods such as hanging or drowning. Pesticides are a leading cause of suicide death in China and India, and the cause of roughly half of suicides worldwide. Pesticides may also explain Asia’s unusual suicide sex ratio, Jha says. In the West, women attempt suicide just as frequently as men do, but they tend to down sleeping pills—and often survive.

The trends in Asia point to a need for innovative prevention strategies. Zhang believes efforts should focus less on mental illness and more on “educating people to have realistic goals in life and teaching them to cope with crisis.” Front and center should be universities and rural women’s organizations, both of which already have active suicide prevention programs in China, he says. Such community-based approaches appear to have been effective in Hong Kong, Yip says. Over the past decade, the territory has rolled out programs for schoolchildren on dealing with stress and outreach groups for older adults. Its suicide rate has fallen 27% since 2003.

But resources in many Asian countries are limited. The vast majority of cities in China and India still do not have 24-hour suicide prevention hotlines. That may make what scholars call means restriction—reducing access to tools commonly used in suicide—a better goal. In Sri Lanka, pesticides once accounted for two-thirds of suicide deaths. Then in 1995, the government took steps to ban the most toxic pesticides. The suicide rate plummeted by 50% in the following decade.

The varying degrees to which mental illness and suicide correlate in East and West may ultimately be beside the point, argues Zhang, who believes a third factor may be the trigger in both regions. Strain theory, which posits that societal pressures, rather than inborn traits, contribute to crime, can help explain suicide, he believes. “Psychological strains usually precede a suicidal behavior, and they also happen before an individual becomes mentally ill.”

When a person is pulled by two or more conflicting pressures, Zhang says, as with “a girl who receives Confucian values at home and then goes to school and learns about modern values and gender equality,” she may be more prone to suicide. Other situational stresses may include a sudden crisis faced by a rural woman lacking coping mechanisms—such as the case of Mrs. Y—or an incident that forces a young man to confront a gap between his aspirations and reality. Zhang found that strain theory held up for his study subjects in rural China. He plans to probe whether it also applies to older Chinese.

Ultimately, Zhang hopes to test strain theory on Americans. The U.S. National Institutes of Health “spends millions and millions of dollars every year on treating mental illness to prevent suicide,” he says. “But no matter how much money we spend, how many psychiatrists we train, or how much work we do in psychiatric clinics, the U.S. suicide rate doesn’t decrease.” It has hovered around 10 to 12 suicides per 100,000 people since 1960.

Such research may be the tip of the iceberg when it comes to debunking long-held ideas about behavior disorders. Alcoholism is another area ripe for exploration, Cheng says: The profile of alcoholics in China contrasts sharply with that in the West. Because of social pressure to drink, Chinese alcoholics are far more likely to be working and married than American counterparts, who are often unemployed and divorced, she says. Suicide, Cheng muses, “is just another example of how environment can change behavior.”

http://www.sciencemag.org/content/338/6110/1025.full