Lead
We all lie awake from time to time, turning worries over in our minds. But what if the deepest fear of all — the fear of death itself — is the thing keeping us from restful sleep? New research published in Death Studies suggests just that: death anxiety is a significant predictor of insomnia, and it operates primarily through the severity of nightmares.
Australian researchers surveyed 515 adults and found that people who reported higher levels of death anxiety also reported worse insomnia. Importantly, this relationship was fully explained — statistically “mediated” — by nightmare severity. In other words, death anxiety doesn’t directly rob people of sleep in a straightforward way. Instead, it fuels more intense and frequent nightmares, and those nightmares are what drive insomnia.
What they found
Led by Rachel E. Menzies from the University of Sydney, the research team recruited 515 adults (70% female, 89% living in Australia) to complete an online survey measuring death anxiety, insomnia severity, nightmare severity, and attachment style. The sample spanned a broad age range, capturing people across different life stages.
Three key findings emerged.
First, death anxiety was positively and significantly associated with insomnia. The higher a person’s fear of death, the more severe their insomnia symptoms tended to be. This held even after controlling for demographic variables.
Second, the researchers tested whether attachment style — the way people form emotional bonds, typically categorized as secure, anxious, or avoidant — might alter the strength of this relationship. It did not. Attachment style showed no moderating effect, suggesting that the link between death anxiety and poor sleep is not meaningfully different for people with secure versus insecure attachment patterns.
Third, and most importantly, the team used a sophisticated mediation analysis (the Hayes PROCESS macro, a standard tool in psychological research) to test why death anxiety leads to insomnia. The answer was nightmares. Nightmare severity fully mediated the death anxiety-insomnia pathway. This means the statistical relationship between fearing death and sleeping poorly disappeared once nightmare severity was accounted for. The fear of death seems to express itself through frightening dreams, and those dreams then disrupt sleep.
Why it matters
Insomnia affects roughly 10% to 30% of adults worldwide, and its causes are complex. Psychological factors such as stress, anxiety, and rumination are well-established contributors, but death anxiety has received surprisingly little attention in the sleep literature. This study suggests that existential dread may play a greater role in insomnia than previously recognized.
The clinical implications are practical. If death anxiety drives insomnia via nightmares, then directly targeting death-related fears in therapy could improve sleep. Existential therapies, cognitive-behavioral therapy (CBT), and even specific nightmare-focused treatments (such as imagery rehearsal therapy) may be especially effective for patients whose insomnia is accompanied by frightening dreams. Rather than treating insomnia as a purely behavioral problem — sleep hygiene, stimulus control, and the like — clinicians may need to ask what patients are afraid of when they close their eyes.
The finding also complements a growing body of research linking existential concerns to mental and physical health. Fear of death has been associated with anxiety disorders, depression, and even health-avoidant behaviors. Adding insomnia to that list underscores just how pervasive the fear of mortality can be — it reaches into the most private hours of the night.
Limits
The study has important limitations. It was cross-sectional, meaning all data were collected at a single time point. This makes it impossible to establish causality or the direction of effects. While the authors propose that death anxiety drives nightmares, which then cause insomnia, it is equally plausible that chronic insomnia heightens death anxiety (sleep deprivation is known to increase emotional reactivity and existential distress), and that nightmares are a consequence of both. Longitudinal or experimental studies are needed to untangle cause and effect.
The sample was predominantly female (70%) and Australian (89%), which may limit generalizability to other populations. Self-report measures were used for all variables, introducing potential recall bias. And although the mediation analysis was statistically rigorous, mediation in cross-sectional data cannot confirm the temporal sequence implied by the model.
Bottom line
Death anxiety is a significant predictor of insomnia, and this relationship is fully explained by nightmare severity. If you find yourself waking from unsettling dreams night after night, it may be worth asking whether a deeper fear of mortality is at the root. The good news is that evidence-based treatments exist for both death anxiety and nightmares, and addressing the existential dimension of poor sleep may offer a path to relief that sleep hygiene alone cannot provide.
Source
Menzies, R. E., Brown, J., Turner, M., Cunnington, D., Burge, M., Dunican, I. C., & Meaklim, H. (2026). Is a fear of death keeping you awake at night? Death anxiety predicts insomnia through nightmare severity. Death Studies, 1-12. https://doi.org/10.1080/07481187.2026.2693544