Symptom Networks in Depression: Temporal Dynamics of Mood, Cognition, and Behavior during Treatment

Purpose: Network models provide valuable insights into the dynamic interplay of symptoms in depression. Key transdiagnostic mechanisms such as repetitive negative thinking, difficulties in emotion regulation, and physical activity contribute to depression's persistence. Understanding their contemporaneous and temporal relationships could help optimize treatment approaches. Methods: Moderately to severely depressed patients (N = 59) from a psychotherapy RCT were assessed using actigraphy (continuously) and ecological momentary assessment (three prompts per day) during treatment (Mdays = 40.90). Data were aggregated per day, and contemporaneous and temporal networks were estimated using multilevel vector autoregression (mlVAR). Results: The contemporaneous network revealed a strong positive association between difficulties in emotion regulation and repetitive negative thinking, suggesting mutual reinforcement within the same day. Mood was negatively associated with both mechanisms, while physical activity was positively linked to mood. The temporal network showed autoregressive effects for all variables, indicating their persistence from one day to the next. Furthermore, mood was negatively associated with difficulties in emotion regulation, but no other relationships were found. In the temporal network, physical activity showed no sustained influence on mood or other symptoms. Conclusions: These findings suggest that difficulties in emotion regulation, repetitive negative thinking, activity and mood are closely interlinked within a given day, reinforcing depressive symptom cycles. However, besides consistent autoregressive effects, their temporal interplay over multiple days appears less pronounced, apart from mood influencing emotion regulation difficulties. The immediate but non-sustained effect of physical activity on mood highlights the need for further research on symptom dynamics and personalized interventions.