What happens at night between 2 AM and 3 AM, when we are not sleeping

Nights, often synonymous with calm and rest, can also hide a darker side. A new study conducted by researchers from the University of Arizona delves into a troubling phenomenon: why do certain nighttime hours seem prone to violent behaviors?

An analysis of 15 years shows that nighttime wakefulness is associated with death by suicide and homicide. This study conducted by the Department of Psychiatry at the College of Medicine of the University of Arizona in Tucson highlights key elements.


Journal of Clinical Psychiatry published a study titled "The risk of suicide and homicide peaks at night: results from the national violent death reporting system, 35 states, 2003-2017". Nighttime wakefulness, age, alcohol consumption, and relationship conflicts are particularly present contributory factors.

Dr. Andrew Tubbs, lead author, explains that disrupted sleep can impair rational thinking and lead to impulsive behaviors in vulnerable individuals. Between 2 AM and 3 AM, the risk of suicide is five times higher and that of homicide is eight times higher, considering the number of people awake and likely to commit or suffer from these acts.

The authors' hypothesis, termed "the mind after midnight," suggests that nighttime wakefulness impairs the brain's complex decision-making functions and reduces rational thinking. This hypothesis is supported by their findings. The nighttime risk is higher among teenagers and young adults, people intoxicated by alcohol, and those experiencing relationship conflicts. However, this risk is not increased among cannabis users or currently depressed individuals.

Adolescents aged 15 to 24 have a three times higher nighttime suicide risk, while an unexpected suicide risk was observed in the elderly at 6 AM. Young adults account for more than half the victims of homicide.

Dr. Tubbs emphasizes that few studies have examined the hourly trends of violent crimes. Future research could clarify what happens in the brain to predispose individuals to these risks and whether evidence-based strategies to improve sleep and reduce nighttime wakefulness can help prevent these tragedies.