Called ‘Mind After Midnight’, the hypothesis suggest that the brain functions differently during the night-time, and we can thank your ancient ancestors.
During the day, human brain activity and molecular levels are more alert, making humans better hunters during the light of day.
However, when it gets dark, the human brain is conditioned to sleep. Humans, and their ancestors, were more vulnerable to becoming the hunted at night, and this is why the human brain is conditioned to actively search out negative stimuli in the dark.
But in modern times, when the threat of attacks at night are greatly decreased, this natural affinity to searching out negative stimuli has adverse effects.
"There are millions of people who are awake in the middle of the night, and there's fairly good evidence that their brain is not functioning as well as it does during the day," said neurologist Elizabeth Klerman from Harvard University, ScienceAlert reported.
"My plea is for more research to look at that, because their health and safety, as well as that of others, is affected."
In the paper, the researchers propose theoretical scenarios where negative thoughts increase in people at night.
A previous study in 2020 found that nocturnal wakefulness is a suicide factor “possibly through misalignment of circadian rhythms”.
"Suicide, previously inconceivable, emerges as an escape from loneliness and pain, and before the costs of suicide are considered the student has acquired the means and is prepared to act at a time when no one is awake to stop them," the authors of the 'Mind After Midnight' hypothesis explain.
Another study in 2020 found that illicit drug use also increased more at night, with a 4.7-fold increase in the risk of opioid overdose.
The latest research concludes more investigation is needed into the factors of nighttime wakefulness in order to protect those most at risk.