Effect of a DBT-Informed Dyadic Intervention (Better Together) on Psychosocial Outcomes in Colorectal Cancer Patient-Spouse Dyads: A Randomized Controlled Trial.

[BACKGROUND] Colorectal cancer (CRC) and its associated treatments cause significant psychological distress for both patients and their spousal caregivers. Traditional psychosocial interventions often focus on individuals rather than dyads, despite the interconnectedness of patient and caregiver wellbeing. While dialectical behavior therapy (DBT) provides evidence-based skills for emotion regulation and interpersonal effectiveness, it has not been systematically adapted for dyadic cancer care.

[AIMS] To evaluate the effectiveness of Better Together, a DBT-informed dyadic intervention, in improving psychological and relational outcomes for CRC patient-spouse dyads. The study also explored whether these effects differed by role (patient vs. caregiver) and assessment time point (active intervention period vs. follow-up period).

[METHODS] In a randomized controlled trial, 254 post-treatment CRC patient-spouse dyads were randomly assigned to the intervention group (7-week DBT-informed sessions plus usual care) or a control group (usual care only). Outcomes (psychological distress, perceived stress, relationship satisfaction, and distress disclosure) were assessed at baseline (T1), post-intervention (T2), and 3-month follow-up (T3). Linear mixed-effects models analyzed intervention effects.

[RESULTS] Intervention effects varied significantly by role and time point. Patients showed greater improvements in psychological distress (Δ = -5.13, p < 0.001) and perceived stress (Δ = -5.30, p < 0.001) from T1 to T2, and these effects were sustained at T3. Caregivers demonstrated no immediate improvements at T2 but significant delayed gains in relationship satisfaction (Δ = 4.75, p < 0.001) and distress disclosure (Δ = 6.27, p < 0.001) during follow-up (T2 to T3). Patterns of change differed significantly between patients and caregivers across outcomes and over time.

[CONCLUSIONS] The BT program effectively improved both individual and dyadic outcomes, with patients benefiting immediately in psychological domains and caregivers exhibiting delayed improvements in relational outcomes during the follow-up period. These findings support implementing phased, role-sensitive dyadic interventions that address the distinct temporal needs of patients and caregivers in cancer care.