Detecting impending symptom transitions using early warning signals in individuals receiving treatment for depression

Drawing on dynamical systems theory, this study investigated whether within-person detected early warning signals (EWS) in momentary affect preceded critical transitions towards lower levels of depressive symptoms during therapy. Participants were 41 depressed individuals who were starting psychological treatment. Positive and negative affect (high and low arousal) were measured five times a day using ecological momentary assessments over four months (M=521 observations per individual). Depressive symptoms were assessed weekly over six months. Within-person rising autocorrelation was found for 89% of individuals with transitions in at least one variable (62.5% in the no-transition group), and in a consistently higher proportion of the separate variables (~44% across affect measures) than for individuals without transitions (~27%). Rising variance was found for few individuals, both preceding transitions (~11%) and for individuals without a transition (~12%). Part of our sample showed critical slowing down, but EWS may have limited value as a personalized prediction method.