People who sleep less than eight hours a day are more likely to suffer from anxiety and depression.
This is because the sleepless are less able to keep away negative thoughts and stay away from negative emotions than those who are sleepy enough.
Published in the Journal of Behavior Therapy and Experimental Psychiatry, the study analyzed 52 adults who have been diagnosed with persistent negative thoughts - which causes boredom, anxiety and stress.
After extensive experiments and analysis, the results showed that lack of sleep - less than eight hours a night - causes people to spend more time focusing on negative things.
Researchers are now carrying out more detailed studies to see how sleep contributes to psychological disorders, hoping that in the future, anxiety and depression can be treated by doing better sleep.