A new study published in the journal Cognitive Therapy and Research has found that people who sleep for shorter periods of time and go to bed very late at night are often overwhelmed with more negative thoughts than those who keep more regular sleeping hours.

People are said to have repetitive negative thinking – a persistent and abstract focus on negative aspects of one’s experience – when they have bothersome pessimistic thoughts that seem to repeat in their minds.

They feel as though they have little control over these contemplations. They also tend to worry excessively about the future, delve too much into the past, and experience annoying intrusive thoughts.

Such thoughts are often typical of people suffering from generalized anxiety disorder, major depressive disorder, post-traumatic stress disorder, obsessive compulsive disorder, and social anxiety disorder.

Previous studies have linked sleep problems with such repetitive negative thoughts, especially in cases where someone does not get enough shut eye.

Dr Jacob Nota and Dr Meredith Coles of the Binghamton University’s Department of Psychology, the authors of the new study, set out to see if there is any link between having such repetitive thoughts and the actual time when someone goes to bed.

The scientists asked 100 undergraduate students at Binghamton University to complete a battery of questionnaires and two computerized tasks.

In the process, it was measured how much the students worry, ruminate or obsess about something – three measures by which repetitive negative thinking is gauged.

The participants were also asked whether they were more habitual morning or evening types, preferring to hold regular hours or to have a sleep-wake schedule that is more skewed towards later in the day,

The team found that people who sleep for shorter periods of time and go to bed later often experience more repetitive negative thoughts than others. This was also true for those participants who described themselves as evening types.

“Making sure that sleep is obtained during the right time of day may be an inexpensive and easily disseminable intervention for individuals who are bothered by intrusive thoughts,” Dr Nota said.

The results also suggest that sleep disruption may be linked to the development of repetitive negative thinking.

The scientists therefore believe that it might benefit people who are at risk of developing a disorder characterized by such intrusive thoughts to focus on getting enough sleep.

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Jacob A. Nota & Meredith E. Coles. Duration and Timing of Sleep are Associated with Repetitive Negative Thinking. Cognitive Therapy and Research, published online December 4, 2014; doi: 10.1007/s10608-014-9651-7