Exploring unique longitudinal associations between cigarette smoking and symptom-level depression among Chinese adult...

It is well-established that cigarette smoking is associated with depression, yet the literature presents conflicting results, with numerous studies suggesting that smoking increases the risk of depression while other evidence indicates that smoking may temporarily relieve depressive symptoms. The network theory of psychopathology implies that the smoking-depression link may exhibit heterogeneity at the symptom level, thereby providing a valuable perspective for understanding these inconsistencies. Accordingly, this study explored unique longitudinal associations between smoking and symptom-level depression among adult males in China, where smoking prevalence is among the highest globally.

Four-wave longitudinal data from the China Family Panel Studies (CFPS) were used, comprising 7,693 Chinese adult males who smoked. A cross-lagged panel network (CLPN) analysis was employed to investigate symptom-level relationships between smoking and depression, and to identify key symptoms within the temporal, directional network.

After controlling for potential confounding covariates, autoregressive effects, and all other symptoms at the previous occasion, the CLPN model revealed divergent associations between cigarette smoking and depressive symptoms. Specifically, earlier smoking was positively associated with later "tiredness" and "pessimism about the future", whereas it was negatively associated with subsequent "loneliness" and "loss of enjoyment". Moreover, certain symptoms, such as "pessimism about the future", emerged as key symptoms.

These findings offer preliminary but novel insights into the ongoing debate regarding the controversial smoking-depression link and contribute to the literature by being the first to explore the networked and dynamic interplay between smoking and symptom-level depression. Although these findings should be considered exploratory due to the modest effect sizes, this study could be a springboard for further investigation into the associations between smoking and depressive symptoms from the psychopathology network perspective.