Background: Major depressive disorder (MDD) is characterized by a high risk for relapses and chronic
developments. Clinical characteristics such as residual symptoms have been shown to negatively
affect the long-term course of MDD. However, it is unclear so far how trait repetitive
negative thinking (RNT) as well as cognitive and affective momentary states, the latter experienced
during daily-life, affect the long-term course of MDD.
Method: We followed up 57 remitted depressed (rMDD) individuals six (T2) and 36 (T3) months after
baseline. Clinical outcomes were time to relapse, time spent with significant symptoms as a
marker of chronicity, and levels of depressive symptoms at T2 and T3. Predictors assessed
at baseline included residual symptoms and trait RNT. Furthermore, momentary daily life
affect and momentary rumination, and their variation over the day were assessed at baseline
using ambulatory assessment (AA).
Results: In multiple models, residual symptoms and instability of daily-life affect at baseline independently
predicted a faster time to relapse, while chronicity was significantly predicted by trait
RNT. Multilevel models revealed that depressive symptom levels during follow-up were predicted
by baseline residual symptom levels and by instability of daily-life rumination. Both
instability features were linked to a higher number of anamnestic MDD episodes.
Conclusions: Our findings indicate that trait RNT, but also affective and cognitive processes during daily
life impact the longer-term course of MDD. Future longitudinal research on the role of
respective AA-phenotypes as potential transdiagnostic course-modifiers is warranted.