Emerging Research Reinforces Links Between Sleep and Suicide

Suicide claims roughly 800,000 lives annually worldwide. And years of research and study have established that early intervention during periods of worsening suicidal ideation (SI) is effective.

Timely intervention remains a challenge because of the rapid onset and progression of SI. Spotting the warning signs remains essential for effective clinical intervention.

The Journal of Clinical Psychiatry has published a wealth of research that can help caregivers at every level. This week, we’re presenting summaries of two recent studies and an insightful commentary – with links – for further review.

New Study Stresses Need for Better Sleep Monitoring to Prevent Suicide

Sleep duration has emerged in more recent research as a potential marker for proximal suicide risk. Multiple studies have shown that shorter sleep duration is linked to increased suicide-related thoughts and behaviors.

However, most studies have been cross-sectional or longitudinal over months or years. Recent evidence suggests that sleep duration might also be relevant for short-term fluctuations in suicide risk. Studies suggest a link between shorter sleep duration, reduced cognitive control, and increased emotional reactivity. These are all factors that can elevate suicide risk.

One significant study – appearing earlier this month in JCP –  found that shorter nightly sleep duration predicted greater severity of next-day SI, even after accounting for other psychiatric symptoms.

Despite these findings, limitations make it challenging to rely on nightly sleep duration as a reliable marker. Studies typically examine past-night or past-month sleep patterns. But the effects of sleep loss on cognitive and affective processes might compound over several nights of shorter sleep. This makes recent cumulative sleep duration a potentially more reliable indicator of suicide risk. A cumulative index of sleep duration averaged over three nights, has shown moderately stable estimates of recent sleep duration and predictive utility for high-impact behaviors in other fields.

Researchers launched this study to address knowledge gaps by looking more closely at the associations between sleep duration and suicide risk using ecological momentary assessment (EMA). This compares a single-night duration and a three-night average as predictors of suicidal desire and intent.

The study recruited participants via social media, focusing on those with severe SI. With an app, participants reported their sleep duration and levels of suicidal desire and intent over a fortnight. Findings indicated that individuals with shorter sleep duration, on average, experienced more severe suicidal desire and intent.

Notably, the research team identified a link between nightly and cumulative sleep durations to increased suicide risk. And cumulative sleep duration showed slightly stronger predictive utility.

These results underscore the importance of monitoring sleep patterns in individuals at risk for suicide and suggest that both nightly and cumulative sleep indices could be useful in clinical settings for anticipating and mitigating suicide risk.

Nighttime Wakefulness Linked to Increased Suicide and Homicide Risks

Disrupted sleep, characterized by poor quality or insufficient duration, could heighten suicide risk. The “Mind after Midnight” hypothesis posits that staying awake during habitual sleep hours increases the risk of impulsive behaviors due to a combination of circadian sleep pressure and sleep deprivation-induced cognitive impairments. Nocturnal wakefulness, occurring during times of social isolation, can exacerbate this risk by leaving individuals without support systems.

Scientists pulled evidence for this hypothesis from patterns of suicide and population wakefulness. Although hourly suicide counts peak around noon, adjusting for the number of people awake shows a threefold increase in suicide risk from midnight to 6 a.m. Studies have confirmed similar nighttime suicide risks in various populations, including military personnel. Nocturnal wakefulness affects cognitive domains by minimizing positive mood, maximizing negative mood, altering risk/reward processing, and compromising executive functions.

Subgroup analyses reveal variations in overnight suicide risk. Adolescents and young adults, whose prefrontal cortex is not fully developed, show heightened risk due to underdeveloped executive functions. Alcohol intoxication, which impairs executive functions, further increases nighttime suicide and homicide risk. Conversely, cannabis use and depressed mood don’t show significant interactions with suicide timing. This could be due to methodological limitations in data categorization and measurement.

The study analyzed 15 years of national data, examining suicide and homicide risks on an hourly basis and across various demographic subgroups. Results showed a fivefold increase in suicide risk and an eightfold increase in homicide risk from 2 to 3 a.m. These findings suggest that nocturnal wakefulness, particularly among vulnerable groups, elevates the risk for dysregulated behaviors.

The study underscores the importance of interventions targeting sleep improvement and reducing nocturnal wakefulness as potential strategies to mitigate these risks. Further research is necessary to develop and test such interventions to prevent these tragic outcomes.

Commentary: Can Sleep Patterns Determine Suicide Risk?

Recent studies have identified sleep complaints as significant predictors of suicide risk. Research has delved into the specifics, examining sleep patterns in the days leading up to suicidal thoughts or actions. Such studies emphasize the importance of recognizing changes in sleep as early warning signs, enabling timely and tailored interventions.

Notably, variations in total sleep time (TST) have emerged as early risk markers, with both shorter and longer habitual TST linked to a higher incidence of suicide attempts within 12 months.

Recent studies employing EMA have shown that individuals who sleep less than their average experience heightened suicidal desire and intent the next day. This has been corroborated in adolescents, where reduced TST and increased sleep onset latency were associated with a “death wish” the next day.

Prolonged wakefulness during usual sleep periods is another risk factor. An Australian study found increased suicide rates overnight, likely due to a combination of sleep deprivation, social isolation, and cognitive deficits. The “Mind after Midnight” hypothesis suggests that nocturnal wakefulness exacerbates these risks. Research indicates a significant rise in suicide and homicide risks during late night hours, particularly among young adults and those under the influence of alcohol.

Alterations in dream content also serve as indicators, with bad dreams, nightmares, and suicidal scenarios in dreams appearing months before a suicidal crisis. Monitoring these changes is simple yet effective for early detection.

Hypnotics, while generally protective against insomnia and suicidal ideation, can paradoxically increase suicidal thoughts and behaviors in some cases. This necessitates careful monitoring when using medications like Z-drugs and dual orexin receptor antagonists (DORAs).

Overall, recognizing and addressing sleep disturbances — whether through changes in TST, nocturnal wakefulness, dream content, or the effects of hypnotics — is crucial. Integrating sleep health into intervention strategies can enhance patient care and save lives, highlighting the need for ongoing research and vigilance in this area.

Further Reading

Weekly Mind Reader: How Gender Influences Suicide

Surgeon General Calls for Social Media Warning Labels

Despair is Killing More Middle-Aged Black and Native Americans