Mar 23, 2026 Gyeonghyun Cho www.health.harvard.edu A growing number of experts say the connection between sleep and mental wellbeing is not simple. It works both ways. Poor sleep can make mental health worse, and mental health struggles can make it harder to sleep. Dr. Lauren Waterman, a psychiatrist who focuses on insomnia, says it is important to understand the difference between sleep deprivation and insomnia. Sleep deprivation usually happens because of outside factors, l