Medicine & TechnologyHaving negative thoughts could be the result of lack of sleep or getting to bed very late at night, a recent Binghamton University study revealed. Repetitive pessimistic thinking was linked to people who get only a few hours of sleep compared to those who get "enough" hours of slumber. And relating sleeping habits to the patterns of behavior participants exhibited, researchers found that there was a large contrast in thought patterns for those who sleep late versus early bed goers.