Why the Mind After Midnight Can Feel Darker

Why the Mind After Midnight Can Feel Darker

In the early hours, the world can often seem a much darker place. Concealed by the night, troubling thoughts may begin to circle in your head; while you lie awake looking at the ceiling, you may find yourself yearning for guilty pleasures such as a cigarette or a carbohydrate-heavy meal.

Considerable evidence indicates that the human mind operates differently when it is awake at night. After midnight, negative feelings generally command more attention than positive ones, hazardous ideas can become more tempting, and inhibitions weaken.

In a 2022 paper reviewing evidence that brain systems work differently after dark, some researchers argued that the human circadian rhythm plays a major part in these important functional shifts.

Their theory, known as ‘Mind After Midnight’, proposes that the human body and mind move through an innate 24-hour activity cycle that shapes emotions and behaviour.

Put simply, our species tends to think, feel and behave in particular ways at particular times. During daylight hours, for example, molecular levels and brain activity are set for alertness. At night, however, our normal patterns of behaviour are effectively switched off.

From an evolutionary perspective, this is unsurprising. People are far better equipped to hunt and gather in daylight, while night is suited to rest; historically, though, humans faced a greater chance of becoming prey after dark.

The researchers suggest that, in response to this elevated danger, attention to negative cues becomes unusually intense at night. Although this may once have enabled us to react to unseen threats, such heightened focus on the negative can influence an altered reward and motivation system, leaving people especially susceptible to risky behaviour.

Sleep Loss and Night-time Risk

When sleep deprivation is added to the mix, this state of consciousness becomes even more troubling.

"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 in 2022 when the study was published.

"My plea is for more research to look at that, because their health and safety, as well as that of others, is affected."

The authors behind the hypothesis offer two scenarios to demonstrate their argument. In the first, a heroin user is able to control their cravings during the day, yet gives in to them at night.

The second concerns a university student with insomnia, who starts to experience hopelessness, loneliness and despair as sleepless nights accumulate.

Either situation may ultimately be fatal. Suicide and self-harm are particularly common during the night. Indeed, some research has found that the risk of suicide is three times higher between midnight and 6:00 am than at any other point in the day.

A 2020 study determined that being awake at night is a risk factor for suicide, "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.

People also use illicit or dangerous substances more often at night. Research conducted in 2020 at a supervised drug consumption centre in Brazil found that the risk of opioid overdose was 4.7 times greater overnight.

What We Still Do Not Know About the Mind After Midnight

Sleep debt and the concealment provided by darkness may account for some of these behaviours, but neurological changes that occur at night are likely to be involved as well.

Klerman and her fellow researchers believe these influences require further investigation, so that people most vulnerable to night-time wakefulness can be properly protected.

So far, the authors noted, no research has explored how sleep deprivation and circadian timing affect an individual's reward processing.

Consequently, little is known about how shift workers with unconventional sleep patterns, including pilots and doctors, manage.

For roughly six hours each day, our understanding of how the human brain functions remains remarkably limited. Whether we are asleep or awake, the mind after midnight remains an enigma.

The study appeared in Frontiers in Network Psychology.

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An earlier version of this article was published in August 2022.