Those who suffer from depression or anxiety may find that getting through each day is a daily struggle. Working up the drive to perform even the simplest tasks might take large amounts of energy, and naturally it would be easy to develop a negative outlook on the world.
Now, a new study suggests that lack of sleep may be behind the negative emotional responses that many anxious and depressed people feel. Researchers at the University of Illinois at Chicago (UIC) point out that anxiety and depression often lead to sleeping problems that may affect an area of the brain that regulates how we react to the world around us.
"Our research indicates sleep might play an important role in the ability to regulate negative emotions in people who suffer from anxiety or depression,” said lead researcher Heide Klumpp, assistant professor of psychiatry at UIC.
The study assessed 78 participants between the ages of 18 and 65 who had been diagnosed with an anxiety disorder and/or a major depressive disorder. Using a device called an actigraph, the researchers measured participants awake time in bed over a six-day period to evaluate sleep efficiency. Before the evaluation, participants were also asked to complete a questionnaire gauging their sleep over the past month and to take part an emotion-regulation task involving reappraisal.
Reappraisal is an exercise where participants are asked to look at an image – in this case a scene of violence such as a war or accident photo – and try to look at it in a more positive way. For example, an image of a woman with a bruised face might be seen as an actress wearing makeup for a role rather than a survivor of violence.
"Reappraisal is something that requires significant mental energy. In people with depression or anxiety, reappraisal can be even more difficult, because these disorders are characterized by chronic negativity or negative rumination, which makes seeing the good in things difficult," explains Klumpp.
Less sleep stresses the brain
The questionnaire revealed that three out of four participants met the criteria for significant sleep disturbance, while the actigraph showed that most the group suffered from insomnia. When comparing data on all the tasks, the researchers found that those who reported poorer sleep on the questionnaire had less brain activity in a particular area of the brain during the reappraisal task. However, those who had more awake time in bed and lower sleep efficiency according to the actigraph had higher brain activity during the reappraisal task, indicating that their brains had to work harder to carry out the task.
"Because the questionnaire and actigraph measure different aspects of the sleep experience, it is not surprising that brain activity also differed between these measures. The questionnaire asks about sleep over the previous month, and answers can be impacted by current mood. Plus, respondents may not be able to accurately remember how they slept a month ago. The actigraph objectively measures current sleep, so the results from both measurements may not match," explains Klumpp.
The researchers say that their findings indicate that sleep plays an important role when it comes to regulating negative emotions, and that those who suffer from anxiety and depression could be at a disadvantage because their conditions tend to inhibit sleep.