Change in psychosocial target processes during prenatal depression intervention: A randomized clinical trial.

Prenatal depression is one of the most common obstetric complications. Psychotherapies alleviate depression during pregnancy, yet less is known about which psychosocial processes are changed during treatment and which psychotherapeutic targets associate with depression symptom improvement. This study addressed these questions using data from a prospective randomized clinical trial (RCT). Adult pregnant individuals, randomized to brief Interpersonal Therapy (IPT; n = 115; age M=29.7 [5.9] years) or active comparison condition of Enhanced Usual Care (EUC; n = 119; M=30.1 [5.9] years) which included integrated maternity support services plus one-on-one counseling session and written psychoeducation, completed measures assessing multiple forms of social support, perceived stress, rumination, attachment styles, and various coping skills at baseline (M=16.7 gestational weeks) and post-intervention at end of gestation (M=35.8 weeks; near term) alongside depression symptom scales across pregnancy. Results of linear mixed-effects models showed that most social support dimensions improved, perceived stress and rumination decreased, and multiple forms of coping changed for participants in both IPT and EUC across pregnancy. Perceived stress and emotionally-supportive coping changed more in the IPT group relative to EUC. Change in depression symptoms across pregnancy was predicted by change in social support dimensions of tangible and positive interactions, perceived stress, rumination, and less behavioral-disengagement coping. Causal mediation analyses showed rumination mediated the link between randomization to treatment group and reduced depression symptoms. Results identifying which psychosocial processes were changed during prenatal depression treatment and associate with symptom relief can inform future clinical research aiming at these target processes to enhance outcomes for distressed pregnant patients.