0476 Mindfulness Enhances Antidepressant Outcomes for Pregnant Women with Insomnia and Depression: A Comparative Effectiveness Randomized Controlled Trial

Abstract Introduction Insomnia affects half of pregnant women and increases risk for depression. Identifying effective treatments for co-occurring insomnia and depression during pregnancy remains a critical priority. Cognitive-behavioral therapy for insomnia (CBTI) improves sleep quality but has limited impact on depression—an effect attributed to persistent cognitive arousal (worry and rumination). Addressing cognitive arousal may enhance depression outcomes in this population. Emerging evidence suggests that mindfulness-based interventions reduce cognitive arousal during pregnancy. This randomized controlled trial (RCT) evaluated the comparative effectiveness of CBTI versus Perinatal Understanding of Mindful Awareness for Sleep (PUMAS), which integrates mindfulness and behavioral sleep strategies. Methods One-hundred pregnant women with DSM-5 insomnia disorder and depression were randomized to CBTI or PUMAS. Clinical outcomes included the insomnia severity index (ISI), Edinburgh postnatal depression scale (EPDS), and nocturnal cognitive arousal via the pre-sleep arousal scale’s cognitive factor (PSASC). Outcomes were assessed before treatment, weekly throughout therapy, then one week posttreatment. Linear mixed models (LMM) using an intent-to-treat (ITT) approach were used to test treatment effects across repeated measures by evaluating Treatment X Time interactions while controlling for relevant covariates. Insomnia remission was operationalized as posttreatment ISI≤7, and depression remission was operationalized as EPDS< 10. Results LMM analyses revealed that both CBTI and PUMAS resulted in insomnia reductions, but that they did not differ from one another (b=-.14, p=.142). Even so, insomnia remission rates were higher for PUMAS than CBTI (78.0% vs 50.0% remission, χ2=8.51, p=.004). Regarding depression, LMM analyses showed that PUMAS produced greater EPDS reductions than CBTI (b=-.31, p<.001), which corresponded to higher depression remission rates for PUMAS (82.0% vs 58.0% remission, χ2=6.86, p=.009). Regarding cognitive arousal, LMM analyses showed that, relative to CBTI, PUMAS produced greater reductions in PSASC (b=-.34, p=.009). Mediation analysis using PRODCLIN revealed that PUMAS-linked reductions in depression were mediated by decreases in nocturnal cognitive arousal. Conclusion Our findings support imbuing insomnia therapy with mindfulness to alleviate nocturnal cognitive arousal, which may enhance antidepressant effects. This suggests that triaging pregnant women to PUMAS may be appropriate for pregnant patients presenting with comorbid insomnia and depression. Support (if any) This study was funded by the National Institute of Mental Health (R34MH130562, PI: Kalmbach).