Critical Slowing Down in Momentary Affect as Early Warning Signal of Impending Transitions in Depression

Based on dynamical-systems theory, in the current study, we aimed to investigate if recurrence of depression is systematically preceded by within-persons early warning signals (EWSs) in positive and negative affect. Ecological momentary assessments were collected five times a day for a period of 4 months (averaging 524 assessments per individual) from 37 formerly depressed individuals discontinuing antidepressant medication. EWSs (increases in window autocorrelation and variance) preceded recurrence of depression in 32.9% of the participants across robustness checks. Compared with participants that remained in remission, participants with a recurrence showed significantly more positive trends in the variance but not in autocorrelation, and the average number of significant EWSs was more than 3 times larger across tested affect variables. Although the results provide the first systematic evidence that EWSs occur more often before the recurrence of depression, the low sensitivity of EWSs poses a substantial challenge for clinical applications.