Simple answer to this question is to have a regular sleep at proper time in the night.
Cognitive Therapy and Research
Researchers have reported that “Duration and Timing of Sleep are Associated with Repetitive Negative Thinking”. They have defined Repetitive Negative Thinking (RNT) as “a perseverative and abstract focus on negative aspects of one’s experience”.
Usually, people complain about repetitive negative thoughts affecting their life in different ways. They have to check their sleep timing and duration. It is better for them to have a regular sleep at proper time. Making the habit of sleeping late at night and giving shorter time to sleep could increase the chances of more negative thoughts. These thoughts can have bothersome pessimistic type of nature. They may cause the person to worry excessively about the future, and think too much about the past. These thoughts are usually developed in people who are suffering from generalized anxiety disorder, post-traumatic stress disorder (PTSD), major depressive disorder, social anxiety disorder, and obsessive compulsive disorder.
Researchers found that people, who have the habit of sleeping for shorter periods of time and go to the bed very late at night, have more negative thoughts as compared to those, who have regular sleeping hours. The same thing has also been found in those people, who consider themselves as evening types. Sleep disruption is also found to be related to increased chances of repetitive negative thoughts.
From this research, it can also be concluded that the risk of developing a psychological disorder such as PTSD, anxiety, or depression can be reduced by taking enough sleep.
Nota, J., & Coles, M. (2014). Duration and Timing of Sleep are Associated with Repetitive Negative Thinking Cognitive Therapy and Research DOI: 10.1007/s10608-014-9651-7