New York - Sleep disturbances, especially nightmares, are common among people who have attempted suicide, new study findings show.

"To the best of our knowledge, this is the first report on an association between nightmares and suicidality in suicide attempters," co-author Nisse Sjstrm, RN of Sahlgrenska University Hospital, Gteborg, Sweden, and colleagues write. However, they add that "our findings of an association between nightmares and suicidality does not imply causality."

Sjstrm and colleagues examined this association in a study of 165 adults, ages 18 to 68 years, who were admitted to Sahlgrenska University Hospital after attempting suicide. The patients were interviewed about their sleep habits, such as whether they had trouble falling asleep or staying asleep, and how frequently they experienced nightmares.

They were also evaluated for intensity of suicidal thoughts, using anxiety and depression scales, along with Suicide Assessment Scale, which determines and rates the symptoms of suicidal thoughts and behaviors.

Most (89 percent) patients reported having at least one type of sleep problem, with difficulty falling asleep as the most common problem (73 percent), the researchers report in the journal SLEEP. In addition, 69 percent said they had trouble staying asleep and nearly 60 percent said they experienced early morning awakening.

Two out of every three patients (66 percent) also reported experiencing nightmares, study findings indicate. "Frequent nightmares was the only sleep variable associated with high suicidality," the researchers report.

After factoring in other variables that may influence degree of suicidality, including other mental diagnoses, the investigators found that patients with frequent nightmares were almost four times as likely to be highly suicidal compared with patients who didn't report having nightmares.

The association of sleep disturbances, nightmares and suicide "seems logical," according to Dr. Clete Kushida, a sleep expert not involved in the study. "But this is the first study to actually show this is true," he said.

Kushida, who is on the American Academy of Sleep Medicine's board of directors, advises that people who are severely depressed or suicidal, or those experiencing any type of sleep disturbance, should "definitely talk to (their) physician about it."

Most adults have occasional nightmares, but they usually diminish in frequency and intensity as people grow older, explained Kushida, who also directs the Stanford University Center for Human Sleep Research, in California.

Frequent nightmares and other sleep disturbances "might be a symptom of an underlying sleep disorder," such as sleep apnea, he said. Emphasizing the importance of getting help for any sleep disturbance problems, Kushida told Reuters Health that if patients' primary care physicians are not receptive to their sleep complaints, "they may want to seek counsel from a sleep specialist."