Adults who suffer chronic sleep problems are more likely to show suicidal tendencies than those without any insomnia complaints, a new study has found.
In the study, researchers found that the more types of sleep disturbances people had, the more likely they were to have thoughts of killing themselves, engage in planning a suicidal act or make a suicide attempt.
"People with two or more sleep symptoms were 2.6 times more likely to report a suicide attempt than those without any insomnia complaints," said the study's lead author, Dr. Marcin Wojnar, a research fellow at the Department of Psychiatry at the University of Michigan in the United States and Associate Professor of Psychiatry at the Department of Psychiatry at the Medical University of Warsaw in Poland.
Scientists have consistently linked sleep disturbances to an increased risk of suicidal behaviour in people with psychiatric disorders and in adolescents, but it has been unclear whether the association also exists in the general adult population.
In the study, scientists examined the relationship over one year between three characteristics of insomnia (difficulty falling asleep, difficulty staying asleep and waking at least two hours earlier than desired) and three suicidal behaviours (suicidal thoughts, planning and attempts) in 5,692 Americans.
About 35 percent of those studied reported experiencing at least one type of sleep disturbance in the preceding 12 months.
The most consistent link was seen for early morning awakening, which was related to all suicidal behaviours.
People with this problem were twice as likely as those with no sleep problems to have had suicidal thoughts in the preceding 12 months, 2.1 times more likely to have planned suicide and 2.7 times more likely to have tried to kill themselves.
Difficulty falling asleep was a significant predictor of suicidal thoughts and planning.
Compared with people who reported no sleep problems, those who had trouble initiating sleep had 1.9 times the risk of suicidal ideas and 2.2 times the risk of planning suicide.
People who had trouble sleeping through the night - waking up nearly every night and taking an hour or more to get back to sleep - were twice as likely to have thought of suicide in the last year and were three times more likely to have attempted it than those who had no sleep problems.
The results were adjusted for several factors known to influence suicide, including substance abuse, depression, anxiety disorder and other mood disorders, as well as chronic medical conditions such as stroke, heart disease, lung disease and cancer.
They were also adjusted for the influence of sociodemographic factors such as age, gender, and marital and financial status.
The study is to be presented on April 1, 2009 at the World Psychiatric Association international congress 'Treatments in Psychiatry.'