When we think about the causes of insomnia, we typically focus on stress, work demands, shift schedules, caffeine, alcohol, drug use, technology, or poor sleep habits. While these are all important contributors, emerging evidence suggests there may be another, often overlooked factor influencing sleep quality. One of these factors is death anxiety. As a co-author of a recently published study in Death Studies, I had the opportunity to work with a diverse team of researchers across Australia to examine whether fears surrounding mortality contribute to insomnia and nightmares in the general population (1).
Background
Death anxiety refers to the fear, concern, or distress associated with one’s own mortality. Although many people rarely discuss death openly, psychologists have long recognised that awareness of mortality can profoundly influence human emotions, behaviours, decision-making, and mental health. Research increasingly suggests that death anxiety may act as a transdiagnostic factor underpinning a range of psychological conditions, including anxiety disorders, depression, obsessive-compulsive disorder, and health anxiety (2).
Sleep and mortality have also shared a close psychological connection throughout history. Sleep involves a temporary loss of consciousness and control, leading some researchers to hypothesise that fears about vulnerability and mortality may contribute to hyperarousal, bedtime worry, and insomnia (3,4). Despite these theoretical links, relatively little research has examined whether death anxiety itself directly predicts sleep disturbance.
Methods
To investigate this relationship, we conducted a large cross-sectional survey involving 515 adults recruited primarily from Australia. Participants completed validated measures of death anxiety, insomnia severity, nightmare severity, attachment style, and generalised anxiety.
Our primary goal was to determine whether death anxiety was associated with insomnia severity. We also examined whether nightmares explained this relationship and whether attachment style influenced the strength of the association. Importantly, we controlled for generalised anxiety to determine whether death anxiety contributed something unique beyond everyday worry and stress.
What Did We Find?
The findings were both statistically significant and clinically meaningful.
We found that individuals reporting higher levels of death anxiety also reported significantly greater insomnia severity. Participants with higher death anxiety reported more severe nightmares, and these nightmares were associated with greater insomnia severity. Approximately 31% of the relationship between death anxiety and insomnia was mediated through nightmare severity.
In practical terms, individuals experiencing death anxiety may be more likely to experience disturbing dream content, which disrupts sleep. This finding aligns with broader evidence demonstrating strong links between nightmares, psychological distress, and insomnia (5,6).
What Does This Mean for Sleep Health?
One of the most important messages from this research is that sleep is not simply a biological process. Sleep is also deeply influenced by psychological and emotional factors (3). Most people struggling with insomnia are not consciously lying awake worrying about death. Instead, mortality concerns may manifest indirectly through intrusive thoughts, hypervigilance, emotional arousal, avoidance behaviours, or recurrent nightmares. These factors can activate the brain’s threat-response systems, making it more difficult to fall asleep or stay asleep throughout the night (3). The findings also highlight the importance of looking beyond traditional sleep hygiene advice. While factors such as caffeine management, regular bedtimes, and screen use remain important, they may not address deeper psychological drivers of sleep disturbance (3,4). For some individuals, unresolved fears, uncertainty, and existential concerns may be contributing to ongoing sleep difficulties.
Workplace Applications
At Melius Consulting, we spend much of our time helping organisations understand the causes and consequences of fatigue. Many organisations focus heavily on rosters, work hours, shift schedules, and sleep opportunity. While these factors remain essential, our findings suggest that understanding why people are not sleeping may be just as important as measuring how much they are sleeping.
In safety-critical industries such as mining, transport, energy, healthcare, emergency services, and defence, insufficient or disturbed sleep can impair alertness, decision-making, emotional regulation, communication, and risk perception. Sleep disruption is often multifactorial, involving operational, environmental, physiological, and psychological contributors.
These findings reinforce the importance of adopting a holistic approach to sleep health and fatigue risk management. Effective programs should integrate sleep education, mental health, resilience training, wellbeing initiatives, psychosocial risk management, and organisational fatigue controls, rather than relying solely on compliance-based fatigue management approaches.
Conclusion
Our study provides evidence that death anxiety plays a unique role in insomnia and that nightmares are an important pathway linking the two. While further research is needed, particularly in clinical and occupational populations, the findings challenge us to think differently about the causes of poor sleep. For some people, what keeps them awake at night may not simply be workload, stress, caffeine, or shift work. It may be deeper concerns about vulnerability, uncertainty, and mortality itself. Understanding these underlying contributors may help clinicians, employers, and individuals develop more effective strategies to improve sleep health, wellbeing, and performance.
Call to Action
At Melius Consulting, we help organisations improve sleep health, manage fatigue-related risk, and optimise human performance through evidence-based solutions. If your organisation is looking to improve workforce sleep, reduce fatigue-related risk, strengthen wellbeing, or implement a fatigue risk management strategy, contact the team at Melius Consulting. We combine the latest scientific research with practical operational experience to help organisations create safer, healthier, and higher-performing workplaces.
Contact us
ian.dunican@melius.com.au or go to www.meliusconsulting.com.au
References
- Menzies RE, Brown J, Turner M, Cunnington D, Burge M, Dunican IC, Meaklim H. Is a Fear of Death Keeping You Awake at Night? Death Anxiety Predicts Insomnia Through Nightmare Severity. Death Studies. 2026. https://doi.org/10.1080/07481187.2026.2693544.
- Iverach L, Menzies RG, Menzies RE. Death anxiety and its role in psychopathology: Reviewing the status of a transdiagnostic construct. Clinical Psychology Review. 2014;34(7):580-593
- Chellappa SL, Aeschbach D. Sleep and anxiety: From mechanisms to interventions. Sleep Medicine Reviews. 2022;61:101583.
- Hertenstein E, Feige B, Gmeiner T, et al. Insomnia as a predictor of mental disorders: A systematic review and meta-analysis. Sleep Medicine Reviews. 2019;43:96-105.
- Delage JP, Côté J, Journault WG, Lemyre A, Bastien CH. The relationships between insomnia, nightmares, and dreams: A systematic review. Sleep Medicine Reviews. 2024;75:101931.
- Gieselmann A, Ait Aoudia M, Carr M, et al. Aetiology and treatment of nightmare disorder: State of the art and future perspectives. Journal of Sleep Research. 2019;28(4)