Enduring effects of brief interpersonal therapy on depression from pregnancy through 1-year postpartum: A randomized clinical trial.

Postpartum depression is prevalent with negative consequences for both mothers and developing infants. Little is known about how much the effects of depression treatment, delivered during pregnancy, persist as relapse prevention through 1-year postpartum. This study evaluated whether improvements in depression symptoms and diagnostic status observed during pregnancy following prenatal treatment (randomized to brief Interpersonal Psychotherapy (IPT) versus Enhanced Usual Care (EUC)) persisted through 12- months postpartum. A prospective, evaluator-blinded, randomized clinical trial (RCT) was conducted among adult pregnant individuals, recruited via routine obstetric care depression screening in general practice OB/GYN clinics, reporting elevated symptoms or as clinically depressed. From this RCT, 230 participants were followed during postpartum: 114 allocated to IPT (age M=29.6 [5.9] years) and 116 to EUC (M=29.9 [5.8] years). Depression symptom scales (Symptom Checklist Depression Scale [SCL-20]; Edinburgh Postnatal Depression Scale [EPDS]) were repeatedly assessed from birth through 1-year postpartum. Structured Clinical Interview for DSM-5 at 12-months postpartum ascertained (Major Depressive Disorder (MDD) rates. Results showed depression symptoms stayed significantly lower for participants who received prenatal IPT compared to EUC: SCL-20 (t(227) = 3.05, P = .0025; d= .41 [.14-.66]); IPT (16.29 [.93] vs. EUC (21.39 [.92]) and EPDS (t(227) = 2.77, P = .006; d= .37 [.11-.63]); IPT (7.33 [.33]) vs. EUC (8.82 [.32]). MDD rate by end of 1-year postpartum remained significantly lower in IPT (4.33 %) compared with EUC (12.93 %), χ2(1)= 5.29, P = .021, OR= 3.20. Findings demonstrate that brief IPT, delivered during pregnancy, exhibits enduring effects for treating prenatal depression with ongoing relapse prevention for postpartum depression.