(PS6-75) The Mediating Role of Behaviour Change on Worry Symptoms During Treatment for Perinatal Generalized Anxiety Disorder: Preliminary Outcomes from a Randomized Controlled Trial

Introduction: Generalized anxiety disorder (GAD) is a leading mental health concern during pregnancy and the postpartum (perinatal) period, affecting 4.1-5.7% of individuals. However, GAD is poorly defined and often unsuccessfully treated, as research devoted to understanding its clinical features is lacking. Excessive and difficult to control worry is the defining feature of GAD however, there is growing interest in clarifying the role of behaviour and its bearing on GAD pathology. While perinatal individuals with GAD have been shown to engage in maladaptive avoidance and safety behaviours to manage their distress, the impact of these behaviours on GAD treatment outcomes remains largely unknown.

Objective: The present study examined if behavioural change mediated the effect of treatment condition on worry symptom change.

Method: Sixty-one pregnant (n = 9) and postpartum (n = 52) participants with primary GAD were randomized to a 6-session perinatal anxiety cognitive behaviour therapy (CBT; n = 31) or psycho-education (PE; n = 30) group. Participants completed measures assessing GAD behaviours (Worry Behaviors Inventory – Perinatal Revised; WBI-PR) and worry (Penn State Worry Questionnaire; PSWQ) at baseline and post-treatment. Hayes PROCESS Macro for the Statistical Software of Social Sciences was used to evaluate the proposed mediation model. Pre- to post-treatment change scores on the PSWQ were the dependent variable, treatment condition (CBT or PE) was the independent variable, and pre- to post-treatment change scores on the WBI-PR were the mediator variable. Preliminary

Results: The total effect [t(60) = 2.43, p = 0.02], and direct effect [t(60) = 2.08, p = 0.03] of treatment condition on worry was statistically significant, such that participation in CBT (as opposed to PE) was associated with greater change in worry symptoms from pre-to-post treatment. However, contrary to our hypothesis, the indirect effect of treatment condition on change in worry symptoms through behavioural change was not significant (b = -0.41 , SE = 0.64, 95% CI [-2.19, 0.28]). Outcomes from an additional ~24 participants will be reported at the time of presentation.

Discussion: While individuals with GAD engage in avoidance and safety behaviours to manage worry, the present study suggests that behavioural change may not be necessary for change in worry symptoms to occur. Given that change in maladaptive cognitions, rather than behaviour, is often the focus of CBT for GAD treatment protocols, this outcome is encouraging. Preliminary results should be interpreted with caution given the small sample size and potential lack of power to detect our desired effect.