Study Contradicts Popular Belief About Seasonality of Suicides

July 8, 2009

(PhysOrg.com) -- Contrary to popular belief, more Americans commit suicide in summer than in winter, and the day of the week when individuals are more likely to take their own lives has shifted from Monday to Wednesday, researchers at the University of California, Riverside have found.

In a paper published online by the journal Social Psychiatry and Psychiatric Epidemiology, Augustine Kposowa, professor of sociology, and graduate student Stephanie D’Auria examined data for all deaths by suicide in the United States over a five-year period, from 2000 through 2004.

Kposowa and D’Auria analyzed the U.S. Multiple Cause of Death Files and found that the highest percentage of suicides (24.6 percent) occurred on Wednesdays and the lowest percentage was reported on Thursdays (11.1 percent). That finding contradicts decades of earlier research, which suggested that suicides peak on Mondays.

“There has been a definite shift from Monday to Wednesday,” Kposowa said. “Wednesday is a strange time, but it holds true for men and women, and for whites and nonwhites.”

One plausible explanation for the Wednesday effect may have to do with the way Americans have increasingly come to view work, as not something pleasurable to do but merely to survive, he said. “A workplace is not somewhere one looks forward to going, but one nevertheless has to be there or else lose one’s source of livelihood. With increased global economic competition, old protections no longer apply, and no one can take anything for granted anymore. Increasingly, uncertainty about job insecurity comes with heightened levels of stress. It is highly likely that the middle of the week (represented by Wednesday) is when these stressors are at their highest.”

A second major finding of the study is that more people are likely to take their lives in summer (26 percent) than in winter (23.8 percent). Springtime is a close second at 25.8 percent.

Kposowa called those results baffling and said they challenge any view of seasonal affective disorder - mood changes related to a change in seasons, sometimes referred to as winter blues - having an effect on when suicides are more likely to occur.

“The United States has changed in very dramatic ways - ways that we do not yet fully understand - particularly with regard to technology,” he said. The sociologist said previous studies that showed suicides peaking in winter (December, January and February) were done before e-mail, cell phones and blackberries permeated American culture, making it easier to stay connected with friends and family during the Christmas and New Year’s holidays.

“We need to refine assumptions we have made about mental states, mental disorders and suicide, especially when we link them to social support and loneliness,” Kposowa said. “In the old days it may have been true that people felt isolated and lonely, therefore suicide may be higher in winter. With information technology, those old ways may no longer apply.”

The mere fact of cold weather in the winter does not necessarily limit social ties or promote depression and higher suicidal behavior, Kposowa and D’Auria wrote. “Disentangling the various ideas raised here presents a clear research challenge in the quest to increase more fully our knowledge of the link between temporal factors and suicide,” they wrote.

It’s possible, Kposowa said, that the higher percentage of suicides occurring in summer and spring is related to the propensity of many Americans to evaluate themselves through “relative deprivation” - the notion of “keeping up with the Joneses.”

“In summer people are traveling and displaying more of their luxuries, such as automobiles, attractive homes, expensive vacations,” he said. “We are constantly comparing what we have and what we think we should have against what others have. Life tends to begin in spring and passions come to life, so to speak. We begin to make these comparisons. Some people decide they are unable to have a better life, that they have failed in life, and thereby come to believe that perhaps life is not worth living.”

Knowledge of day or season when suicides are more likely to happen could help clinicians and therapists in advising patients and potential victims, Kposowa and D’Auria suggested.

“A clinician could become more proactive, whether through medication or advice, thereby intervening to prevent death,” they wrote. “… If psychological and certain social problems are significantly more likely to be experienced on Wednesday, then future research could try to disentangle what these problems are … .”

The UCR researchers also found that the risk of suicide is greater for individuals who live in states with higher suicide rates, perhaps because a high suicide rate increases awareness of suicide and creates attitudes favorable to suicidal behavior; and that the risk of suicide decreases in states with proportionally larger numbers of physicians.

Provided by University of California, Riverside