Scientists working with adults who fixate on negative thoughts have noted a link between this distressing compulsion and poorer-quality sleep, as well as shorter sleep duration.
Repetitive negative thinking occurs when a person compulsively lingers on thoughts and stimuli that are distressing and unhelpful, which often leads to a decreased quality of life and the emergence of mental health problems, tied to depression and anxiety, in particular.
Prof. Meredith E. Coles and Jacob A. Nota, both of whom are from the State University of New York at Binghamton, conducted a study that focused on the link between repetitive thoughts of moderate and high intensity — also referred to as “worry” and “rumination,” respectively — and an individual’s nightly sleep duration and habits.
Their findings have been reported in the Journal of Behavior Therapy and Experimental Psychiatry.
The researchers recruited 52 participants aged between 18 and 65, all of whom had scored highly on the Perseverative Thinking Questionnaire, which is a test that aims to measure an individual’s level of repetitive negative thinking.
For the purpose of this study, the participants were shown various pairs of images — both neutral and emotionally evocative — and their degree of attention was tested by following their eye movements.
The team also collected information about the participants’ sleep cycles, recording data about how long they tended to sleep every night and around what time they normally fell asleep.
Prof. Coles and Nota observed that the participants who reported frequent sleep disturbances also found it more difficult to stop focusing on any negative stimuli they were exposed to, suggesting a link between poor sleep and the preponderance of intrusive thoughts.
“We found,” explains Prof. Coles, “that people in this study have some tendencies to have thoughts get stuck in their heads, and their elevated negative thinking makes it difficult for them to disengage with the negative stimuli that we exposed them to.”
“While other people may be able to receive negative information and move on, the participants had trouble ignoring it,” she adds.
Overall, Prof. Coles and Nota found that the shorter a person’s sleep duration, the longer it took them to shift their attention away from negative stimuli. The same was true for participants who found it difficult to fall asleep in the first place.
“We realized over time that this might be important — this repetitive negative thinking is relevant to several different disorders like anxiety, depression, and many other things,” says Prof. Coles.
“This is novel in that we’re exploring the overlap between sleep disruptions and the way they affect these basic processes that help in ignoring those obsessive negative thoughts.”
Prof. Meredith E. Coles
However, the researchers do warn that their study has some limitations — particularly the fact that the association between disturbed or short sleep and the persistence of recurring negative thoughts does not necessarily indicate causation.
Furthermore, the lack of a control group may suggest that rumination may not be uniquely, or even primarily, characteristic of people with poor sleeping habits.
Nevertheless, they encourage ongoing focus on the importance of sleep to thought processes and the attention span, concluding that it is necessary “to understand how sleep and circadian rhythm disruptions interact with the allocation of attention.”
If further studies replicate their current findings, they add, this could mean that in the future we may be able to better treat and prevent conditions such as anxiety and depression by modifying our sleep patterns accordingly.