COVID-19 pandemic lockdown linked to impaired mood homeostasis

The COVID-19 pandemic lockdown appeared associated with a significant reduction in individuals’ mood homeostasis, according to results of a cohort study published in JAMA Psychiatry.

“The impact of lockdowns implemented in response to [COVID-19] on mental health has raised concerns,” Maxime Taquet, BMBch, PhD, of the department of psychiatry at University of Oxford and Oxford Health NHS Trust in the U.K., and colleagues wrote. “Understanding the mechanisms underlying this impact to mitigate it is a research priority. We hypothesized that one mechanism involves impaired mood homeostasis (i.e., failure to stabilize mood via mood-modifying activities).”

The investigators collected self-reported data via ecological momentary assessment of Dutch students 4 times daily between March 16 and March 29. The Netherlands government announced lockdown measures on March 23. Data were included of 78 students, of whom 76% were women, and the mean age was 20.4 years. They defined mood homeostasis as the extent to which participants preferred to engage in pleasant activities at times when their mood was low to thus stabilize their mood, and they recorded each participant’s average change in mood associated with different activities. Using a one-item screener, the researchers assessed participants’ history of mental illness at study onset. Further, they used linear regressions to assess mood homeostasis change from before to during lockdown and whether this change was linked to mood changes or changes in the range of undertaken activities, as well as whether mental illness history moderated this change. They estimated the potential association of changes in mood homeostasis with risk for depression using simulations.

Results showed significantly higher mean mood homeostasis before vs. during lockdown (mean difference = 0.09; 95% CI, 0.03-0.15). Participants’ mood score before lockdown was inversely proportional to the pleasantness of activities in which they later engaged. Participants’ low mood was associated with a tendency to later engage in activities that consistently increased their mood by a mean score of 0.75; however, during lockdown, low mood and subsequent activity engagement increased their mood by a mean score of 0.34, and doing so could further decrease mood. Each 0.1-point reduction in mood homeostasis was linked to an average mood reduction of 1.9 points (95% CI, 1.3-3.6), which was enough to change someone’s mean mood score from population average to its bottom quartile. From before to during lockdown, the change in mood homeostasis was linked to a reduction in the range of activities. Individuals with vs. without a history of mental illness exhibited significantly greater reductions in mood homeostasis. Lower mood homeostasis linked to the lockdown appeared to increase risk for depressed mood episodes compared with participants’ baseline incidence.

“How mood homeostasis changes with interventions could provide a fruitful avenue to mitigate the impact of the pandemic on mental health,” Taquet and colleagues wrote.