Transitions in depressive symptom states among adults with subthreshold depression: Associations with lifetime trauma exposure and combined lifestyle in a multistate Markov study.
BACKGROUND Subthreshold depression is common, but whether lifetime trauma exposure and combined lifestyle are differentially associated with symptom transitions remains unclear. METHODS We analyzed a prospective community cohort in Shenzhen, China, of adults aged 18-65 years with a Patient Health Questionnaire-9 (PHQ-9) score ≥ 5 and no depressive disorder at baseline. Depressive symptom states (Normal, Mild, and Moderate/Severe) were assessed repeatedly over 36 months. Continuous-time multi-state Markov models estimated transition intensities, probabilities, and hazard ratios (HRs) for lifetime trauma exposure and a five-component combined lifestyle score, adjusting for demographic, socioeconomic, and health-related covariates. RESULTS Among 2361 participants (mean age, 37.30 years; 61.9% women), recovery transitions were more frequent than worsening transitions. The monthly Mild-to-Normal intensity was 0.131 (95% CI, 0.100-0.171), 2.47 times the Mild-to-Moderate/Severe intensity; Moderate/Severe-to-Mild was highest (0.205; 95% CI, 0.158-0.272). Lifetime trauma exposure was associated with lower Mild-to-Normal (HR, 0.54; 95% CI, 0.42-0.69) and Moderate/Severe-to-Mild rates (HR, 0.52; 95% CI, 0.41-0.65). Unfavorable lifestyle was associated with a lower Mild-to-Normal rate (HR, 0.70; 95% CI, 0.53-0.92) and a higher Mild-to-Moderate/Severe rate (HR, 1.60; 95% CI, 1.13-2.25). Those with both exposures had the lowest Mild-to-Normal rate (HR, 0.39; 95% CI, 0.26-0.59) and a higher Mild-to-Moderate/Severe rate (HR, 1.69; 95% CI, 1.05-2.73). CONCLUSIONS Lifetime trauma exposure was associated with lower recovery rates, whereas an unfavorable lifestyle was associated with lower recovery and higher worsening rates. These associations may inform trauma-informed assessment and lifestyle support for adults with subthreshold depression.