Fluctuations in Chronotype May Indicate Changes in Depressive Symptoms

People with depression and/or anxiety rarely change their chronotype identification over the long term, yet most chronotypes shift to become slightly earlier over a 7-year period, according to study results published in Depression and Anxiety. Furthermore, changes in depressive but not anxiety symptoms were associated with an advance in chronotype, which refers to a person’s preferred sleep-wake cycle. Individuals roughly split into later/evening or earlier/morning chronotypes.

Researchers examined the longitudinal association between chronotype and the change in the severity of anxiety and depressive symptoms in patients with a current or past diagnosis of anxiety or depression. They gathered data from The Netherlands study of depression and anxiety (NESDA) and focused on the 2- and 9-year follow-up waves of NESDA. The investigators assessed chronotype with the Munich chronotype questionnaire and determined symptom severity with reliable scales.

Over the 7-year period, chronotypes were considered moderately stable (r = 0.53; P <.001) in the sample (N=1417; 65.98% women). The corrected midsleep on free days measure at 9-year follow-up was 10.8 minutes earlier than the 2-year follow-up value, suggesting that patients reported either going to bed or falling asleep 10.8 minutes earlier.

In an adjusted analysis controlling for possible confounders, the researchers found an association between reductions in the severity of depressive symptoms with advancement in chronotype (B, 0.008; P =.003). There were no findings in terms of alterations in anxiety symptoms. In post hoc analyses, stable and delayed chronotype groups did not demonstrate any association between changes in chronotype and symptom severity. However, the analysis confirmed the prior findings in the advanced chronotype group demonstrating a relationship between decreased depressive symptoms and earlier sleep-wake patterns (B, 0.009; P =.010).

A study limitation included the use of an assessment tool that does not adjust for other outcomes that could have had an impact on patients’ sleep timing over the 7 years, including work times and having children.

Based on their findings, the researchers noted that “monitoring sleep duration and changes in chronotype might therefore be a way to complement the current clinical evaluation of persons suffering from depressive symptoms.”

Reference

Druiven SJM, Hovenkamp-Hermelink JHM, Knapen SE, et al. Stability of chronotype over a 7-year follow-up period and its association with severity of depressive and anxiety symptoms [published online February 17, 2020]. Depress Anxiety. doi:10.1002/da.22995