Moderators and Mediators of Outcome in an Internet-Based Behavioural Activation Trial for Postnatal Depression (Netmums).

Abstract

Purpose: Postnatal depression (PND) has significant negative outcomes for both mother and baby. The literature indicates that cognitive behavioural interventions can be effective and efficacious treatments, less is known about what mechanisms underpin change in such interventions. The present study aimed to explore severity of depression as a moderator and Behavioural Activation (BA) as a possible mediator of treatment outcome in an online BA intervention for PND. Methods: Follow-up of postnatal women participating in a feasibility Randomised Controlled Trial (RCT) of Netmums, an online BA treatment with telephone support. Results: There was no evidence to support the hypothesis that severity of depression acted as a moderator for treatment outcome. No mediation effects for BA were found. Rumination and avoidance did predict treatment outcome, but this did not differ between the treatment and control group. Post Hoc sudden gains analysis revealed that 48.90% of the treatment group sample experienced a sudden gain. Those who experienced a sudden gain had better post intervention outcomes. Conclusions: The findings have important implications for both theory and the design of future interventions. Future research should consider collecting weekly measures from both treatment and control groups.