Impact of cognitive-affective and somatic symptoms in subthreshold depression transition in adults: Evidence from Depression Cohort in China (DCC)

Symptoms of subthreshold depression may differentially affect the illness transition. We examined the impact of cognitive-affective and somatic symptoms on different subthreshold depression transitions as well as risk factors influencing the aforementioned symptoms changes.Adults with subthreshold depression in the Depression Cohort in China were enrolled. Data collection was conducted at baseline, 6 and 12 months from 2019 to 2020. Cognitive-affective and somatic symptoms were assessed using the Patient Health Questionnaire-9. A total of 993 participants completed 12-month follow-up and were divided into persistent, intermittent and remission groups according to change in depressive symptoms. The longitudinal change of cognitive-affective and somatic symptoms in the three groups, as well as risk factors was analyzed using the generalized linear mixed-model.There were 24.07 %, 34.04 % and 41.89 % of participants proceeding into persistent, intermittent and remission subthreshold depression groups, respectively. Cognitive-affective symptoms were the core symptoms for predicting the deterioration in persistent subthreshold depression (t = 2.48, P = 0.013), whereas somatic symptoms improved over time (t = -2.82, P = 0.005). Anxiety symptoms were the primary risk factors for worsening cognitive-affective symptoms (P < 0.001), following by insomnia symptoms, age, marital status, resilience and social functions. Somatic symptoms were affected by insomnia symptoms, anxiety symptoms and Body Mass Index successively.Major Depressive Episode was not explored in follow-up.Cognitive-affective symptoms in subthreshold depression are at greater risk of illness deterioration. Future studies should endeavor to identify specific risk factors in different symptoms to forestall the transition from subthreshold to Major Depressive Disorder.