Suicidal Behaviors Know No National Boundaries

From developed to third-world countries, being female, younger, less educated, and unmarried and having a mental illness consistently predispose people to experiencing suicidal thoughts, plans, and attempts, according to an international survey published in the February British Journal of Psychiatry.

The survey data, derived from the World Health Organization World Mental Health Survey Initiative, provide a cross-national look at the similarities in the patterns of suicidal ideation and behaviors. Nearly 85,000 people in 17 countries, including Nigeria, Mexico, United States, Japan, New Zealand, China (Beijing and Shanghai only), Belgium, Ukraine, Israel, and Lebanon, were interviewed.

The study authors, led by Matthew Nock, Ph.D., an associate professor of psychology at Harvard University, found the average self-reported lifetime prevalence of suicidal ideation to be about 9.2 percent. The overall lifetime prevalence for actual suicide plans was 3.1 percent, and for attempts, 2.7 percent.

“The relatively high cross-national rates of suicidal behaviors highlight the scope of this problem and underscore the need for suicide prevention efforts,” Nock told Psychiatric News. He particularly noted the “strong consistency” of suicidal behavior patterns in many countries around the world.

Being female, less educated, and never married were factors that consistently raised the risks of suicidal thoughts and behaviors across all countries despite some variability in geographic, economical, and cultural characteristics. Age was also a consistent and significant factor and inversely related to the likelihood of having suicidal thoughts. Not only were youth more likely to think about suicide, but an earlier age of onset for suicidal thoughts significantly predicted actual plans and attempts among those who had suicidal thoughts. These observations, the authors concluded, have “significant implications for the prediction and prevention of suicidal behaviors” for public health efforts.

Beyond sociodemographic characteristics, the presence of psychiatric disorders was a major contributing factor to the risk of suicidal thoughts and behaviors in every country in the analysis. Wealthy and low-income countries differed in the types of psychiatric disorders that had the largest impact. The presence of a mood disorder was the strongest predictor of suicidal ideation, plans, and attempts in wealthy countries, while the presence of impulse-control disorder was more significant in low- and middle-income countries.

“This difference between the high-income and low-income countries was somewhat surprising and requires further study,” Nock said. “It highlights the importance of impulse-control disorders in the prediction of suicidal behaviors. It is not just depressive disorders that increase the risk of suicidal behaviors.”

The authors also discovered that about 60 percent of all first suicide attempts occurred within one year after people started having suicidal thoughts. This showed how quickly the thought of suicide can drive people toward acting on it. This observation and the spike in suicide risks in adolescence and young adulthood “highlight the importance of identifying those with suicidal thoughts early and targeting prevention programs toward this high-risk period,” Nock indicated.

A study of Danish men published in the January Journal of Epidemiology and Community Health provides support for many of the risk factors identified in the WHO survey. Merete Osler from the Institute of Public Health at the University of Copenhagen and colleagues found a significant association between mental disorder at age 18 and increased risk of suicide and suicide attempts in over 9,000 Danish men born in 1953. A low educational level (no more than a basic school education) was again identified as a risk factor for suicide attempts. Low body mass index and low cognitive test score at the age of 18 were also identified as having some effect.

In addition, a group of researchers linked short length at birth to suicide attempts in a study of more than 300,000 Swedish men. This link was stronger in violent suicide attempts than nonviolent attempts. The authors hypothesized that certain types of underdevelopment in fetal growth, reflected by shorter length at birth, may be the underlying mechanism for altered serotonin metabolism of the fetus. The altered fetal serotonin metabolism may affect the prefrontal cortex function and increase impulsivity and aggression, leading to greater tendency for violent suicide in adulthood. The study was published in the February Journal of Epidemiology and Community Health.

“Cross-National Prevalence and Risk Factors for Suicide Ideation, Plans, and Attempts” is posted at<bjp.rcpsych.org/cgi/content/full/192/2/98>. More information about the World Mental Health Survey Initiatives is posted at<www.hcp.med.harvard.edu/wmh>.“ Impaired Childhood Development and Suicidal Behaviour in a Cohort of Danish Men Born in 1953” is posted at<jech.bmj.com/cgi/content/full/62/1/23>.“ Fetal and Childhood Growth and the Risk of Violent and Nonviolent SuicideAttempts: A Cohort of 31,8953 Men” is posted at<jech.bmj.com/cgi/content/full/62/2/168>.▪