Sleep studies have shown that going to bed after midnight can harm mental health. How does this happen? Researchers at Stanford Medicine examined this in a group of nearly 75,000 middle-aged and older adults (the average participant was 63.5 years old, with an average sleep duration of around seven hours). First, they determined each person's chronotype, dividing them into "night owls," "early birds," and a mixed group. The participants' mental health was assessed based on their medical records. A bedtime of 1:00 a.m. was considered late (adjusted to the average age of participants - younger individuals, such as students, were not included since they typically lead a different lifestyle).
The analysis showed that people who fall asleep before 1:00 a.m. are less likely to experience mental and behavioral disorders, depression, or anxiety compared to those who go to bed later - regardless of their chronotype. Both "night owls" and "early birds" who went to bed after 1:00 a.m. experienced similar problems. It turned out that early risers, as well as those who slept in but stayed up late, had a higher incidence of mental health issues, including depression and anxiety. "Night owls" had the hardest time when living in line with their chronotype. Their likelihood of being diagnosed with a mental health disorder was 20% to 40% higher compared to the rest of the participants. "Early birds" who woke up early generally had the best mental health.
"We found that matching one's chronotype wasn't the key issue, but rather that delaying sleep is not good for mental health. The key question is: why?" said Dr. Jamie Zeitzer, professor of psychiatry and behavioral sciences and co-author of the study.
Why Does Going to Bed Late Harm Mental Health?
The researchers aren't entirely sure. It could be that people make more unhealthy decisions at night, such as drinking alcohol, overeating, having suicidal thoughts, or using drugs. Another explanation is offered by the study's author. He introduces a hypothesis about something called the "mind after midnight." According to this hypothesis, the neurological and physiological changes that occur late at night may promote impulsiveness, negative moods, impaired judgment, and a tendency to take unnecessary risks. The researchers are now planning new studies to determine whether it’s specific behaviors undertaken late at night, rather than the time of falling asleep, that are linked to poor mental health.
