Negative moods substantially increased, and concentration problems increased slightly.
"Negative moods naturally dissipate over time," reported researchers in the study, published by the American Psychological Association.
Negative moods have been linked to dehydration.
However, some negative moods, such as sadness and guilt, have been found to promote helping.
The researchers found no evidence for the winter blues, the common assumption that short winter days contribute to negative moods.
The new research on negative moods, however, suggests that sadness comes with its own set of benefits and that even our most unpleasant feelings serve an important purpose.
In general, positive moods, such as happiness and contentment, encourage bystanders to notice emergencies and provide assistance, whereas negative moods, such as depression, inhibit helping.
Unless students are artsy, where negative moods might stimulate imagination or provide material, we would match people with such moods with smaller schools that provide good emotional support".
Nevertheless, their speculation is part of a larger scientific re-evaluation of negative moods, which have long been seen as emotional states to avoid.
