A lot of emphasis today is on diet and exercise and its importance for one's mental health. What about sleep? I believe it to be very underrated, however sleep deprivation can have a major impact on one's mental functioning. In a small study it was found that higher levels of repetitive negative thinking (RNT) are associated with reduced sleep duration. Delayed sleep timing was associated with more obsessive-compulsive symptoms (Nota, Coles, 2015). So sleep tight and stay bright!

References:
Nota, J., Coles, M. (2015) Cognitive Therapy & Research (Volume 39 (issue 2), p.253-261)