Linking Nightmares to Suicidal Behavior Doesn't Add Up

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Nightmares via Shutterstock Nightmares via Shutterstock

In trying to determine whether nightmares and suicidal behavior are in any way related, perhaps the first question that surfaces relates to causation. Are nightmares brought on by those who are plagued with thoughts of suicide? Or are individuals who experience nightmares more often than most more likely to have suicidal thoughts and tendencies?

That's essentially the underlying quandary of a recent study published in the Journal of Clinical Sleep Medicine, which concludes that a "relationship between nightmares and suicidal behaviors is partially mediated by a multistep pathway via defeat, entrapment, and hopelessness when working with clients who have experienced trauma." The study's authors add that these are unique findings, as this relationship has not been shown before.

While that assessment attempts to link the two issues, the study appears suspect in more ways that one. It relies on questionnaire-driven data; it's short on subjects; and since nightmares are subjective there's no scientific way to verify that they occurred, or to what degree.

The research was headed by Donna L. Littlewood, the study's principal investigator and a PhD researcher in medical and human sciences at the University of Manchester. She and her team collected data from 91 subjects who had post-traumatic stress syndrome. Fifty-one of these currently met PTSD criteria, while another 24 had been previously diagnosed with PTSD. (Why the remaining 16 subjects were not included in either of these groups was not disclosed.)

"PTSD increases the risk of suicidal thoughts and behavior," Ms. Littlewood wrote, "and our study shows that nightmares, a hallmark symptom of PTSD, may be an important treatment target to reduce suicide risk."

PTSD affects roughly 8 percent of American adults, according to the National Center for PTSD.

The participants answered questions to measure variables associated with suicidal behavior. Littlewood's team then looked at the frequency and intensity with which participants matched certain items on clinician-administered PTSD scales to measure nightmares.

The team's results found attempts, plans or thoughts of suicide in 62 percent of participants who had reported experiencing nightmares. Conversely, they found these suicidal traits in only 20 percent of nightmare-free participants.

According to the researchers, nightmares induce negative thoughts and feelings -- such as those of defeat or hopelessness -- that build on preexisting thoughts or actions associated with suicide. This cycle is likely most pronounced in those with PTSD, since, according to the study's authors, as many as 8 in 10 PTSD patients have nightmares within three months of a trauma.

Unfortunately, these results are hard to embrace. Just because those with nightmares have a higher incidence of having suicidal thoughts than those without, that does not necessarily indicate causation. And even if nightmares could be somewhat measured -- for instance, where sleeping participants were monitored for respiratory fluctuations, and their brain activity was tracked using sensors -- it's difficult to accept the author's conclusion that nightmares can contribute to suicidal acts.