Abstract
BACKGROUND: Depression is a complex mental disorder, with much unknown about its dynamic symptom network. Investigating the topology and temporal dynamics of this network can uncover pathological mechanisms. METHODS: This is a longitudinal study with a 2-year follow up. At wave 1, 4840 adults without depressive symptoms were selected from the 2016 China Labor-force Dynamics Survey and included in the study. At wave 2, 1217 subjects who developed depression were assigned to the study group, and 3623 who remained healthy to the control. Psychological symptom networks were constructed and compared between waves and groups. RESULTS: The central symptom node shifted from “feeling depressed” to “lack of motivation”, suggesting a transition from sadness to pervasive amotivation as the core of depression. Overall network connectivity significantly increased, with doubled connection density and intensified interconnections (global strength 4.39 vs. 8.29; mean edge weight 0.02 vs. 0.04; both p < 0.001). Multiple symptom pairs showed increased edge weights or new connections, indicating heightened interconnectedness during depression. LIMITATIONS: The assessment of depressive symptoms relied on self-report measures, which may be subject to biases and variations in individual interpretation. CONCLUSIONS: This study provides novel insights into dynamic changes in the central and bridge symptoms of depression over two years. Results highlight the interconnectedness and mutual reinforcement of symptoms, with shifts in core nodes and intensified connections. Findings provide valuable understanding of underlying mechanisms, with implications for early detection, interventions aimed at disrupting symptom cycles, and developing targeted treatments to alleviate this pervasive, disabling disorder. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12888-025-07124-4.