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

Abstract 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 psychotherapeutic interventions. Methods Moderately to severely depressed patients ( N = 59) from a psychotherapy randomized controlled trial (RCT) were assessed using actigraphy (continuously) and ecological momentary assessment (three prompts per day) during treatment (M days = 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 ( r = 0.50), indicating a strong same-day co-variation. Mood was negatively associated with both mechanisms (difficulties in emotion regulation: r = − 0.29; repetitive negative thinking: r = − 0 .36), while physical activity was positively linked to mood ( r = .0.19). The temporal network showed positive autoregressive effects for all variables, indicating their persistence from one day to the next. Furthermore, better-than-average mood (within person) was associated with fewer difficulties in emotion regulation on the next day (β = − 0.10), but no other relationships were found. In the temporal network, physical activity showed no sustained influence on mood or other symptoms. Conclusions These findings indicate that difficulties in emotion regulation, repetitive negative thinking, activity, and mood are closely interlinked within the same day. However, besides consistent autoregressive effects, their temporal interplay over multiple days appears less pronounced, apart from mood influencing difficulties in emotion regulation. The immediate (same day) co-fluctuation between physical activity and mood, without cross-day carry-over, highlights the need for further research on symptom dynamics. Our findings are hypothesis-generating with respect to candidate targets and potential timing; any personalization should be tested prospectively (e.g., in within-person randomized designs).