Suicide is the second-highest cause of death worldwide for adults between 24 and 44 years old. Last year, more than 40,000 Americans ended their own lives. Researchers have long sought to identify and make sense of risk factors for suicidal behavior and, since the early 2000s, have found an unusually strong link between suicide and disturbed sleep. More narrowly focused work has honed in on specific sleeping disorders that, alone, appear to increase one’s risk of self-harm. Nightmares are a big one.
The connection between nightmares and suicide, however, has been poorly understood. But now, a team of researchers has laid out an explanation of the psychological process by which recurring, upsetting dreams leave someone vulnerable to taking their own life. In a study published this month in the Journal of Clinical Sleep Medicine, researchers found a domino effect in which nightmares trigger a specific series of linked emotions that can leave someone more vulnerable to suicide.
The researchers investigated the basis of the nightmare-suicide connection by focusing on people with PTSD symptoms. Nightmares, a core feature of PTSD, plague an estimated 90 percent of trauma victims. (Acknowledgement of recurring nightmares among war vets dates back to WWI, decades before PTSD would become an official disorder, replacing the neutered designation of “shell-shocked.”)
For the study, 91 participants answered questions about the severity and frequency of their nightmares, suicidal behavior, depression and insomnia. In this case, nightmares refer specifically to distressing dreams about the traumatic experiences at the roots of participants' disorders. So, veterans’ nightmares, for example, may have concerned combat. Researchers also assessed participants' feelings of defeat, entrapment and hopelessness by asking them to agree or disagree with statements — here’s an example of a statement for each feeling:
- Defeat: “I feel that I have not made it in life.”
- Entrapment: “I would like to get away from other more powerful people in my life.”
- Hopelessness: “I look forward to the future with hope and enthusiasm”
Both insomnia and depression, jointly and individually, are associated with nightmares and suicide. So, researchers wanted to isolate direct links within this interconnected web of feelings, behaviors and disorders. They analyzed participants’ responses in multiple ways, and figured out that nightmares predicted suicidal behavior, whether or not participants also had insomnia or depression. Sixty-two percent of participants who experienced nightmares, compared to 20 percent of those who didn't, also reported suicidal tendencies or thoughts.
The data, once compiled, jibed with their proposed psychological model:
As for the explanation? Well, nightmares trigger defeat. When people can’t stop thinking about the source of their trauma (here, in their sleep), they feel defeated by the experience or event in question. In turn, defeat is associated with entrapment and hopelessness. People feel as though they can’t escape from the trauma they can’t conquer, and develop a pessimistic attitude about the future. In other words, they begin to feel like prisoners of their trauma and don’t see a way to escape the cycle of torment other than through suicide.
It’s important to understand the mental process that connects recurring nightmares and suicide in order to minimize resulting harm. Merely acknowledging a link does serve a purpose: Awareness, which is vital to prevention. But fixing a negative, recurring phenomenon hinges on making some sense of it. This research is a productive first step.
The proposed multi-step process, however, isn’t the only explanation researchers have floated regarding the upsetting connection, but it is the first detailed psychological theory. In another study, from 2015, for example, researchers developed a more general, neurologically based hypothesis to reconcile individual links between insomnia, nightmares and suicide, which they suspected share some common factor. “One possibility,” study authors wrote, “is that sleep disturbance results in being awake at night, and being awake at night also confers risk.”
The gist of their hypothesis, called "hypofrontality," is that being awake when we’re biologically not supposed to be (i.e., in the middle of the night) somehow results in reduced executive function, an umbrella term for cognitive abilities including logical thought. This state of diminished reasoning, in turn, increases one’s vulnerability to suicidal ideation.
Whether or not these early-stage theoretical explanations bear out, they keep the ball rolling. And when we're up against a slippery, stubborn public-health problem like suicide, we can't afford to lose momentum.