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
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
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
"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
"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>.▪