Congruence couple therapy for alcohol use and gambling disorders with comorbidities (part II): Targeted areas and mechanisms of change.

Study of change mechanisms is important to advance theory development and to reveal the active components that make a critical difference in treatment. Improved outcomes in a randomized controlled trial that favored Congruence Couple Therapy (CCT) vs individual-based Treatment-as-Usual (TAU) were correlated within each group. Partial correlations were used to test for mediation effects. The aggregate correlation coefficient of improved variables in addiction and mental health, couple adjustment, emotion regulation (ER) and life stress was moderate for CCT and weak for TAU. CCT showed greater number of mediating effects among improved variables than TAU. The prominence of the process mechanism of improved ER with its mediating effects for addiction and psychiatric symptoms evidenced in both groups is noteworthy, but ER improvement was significantly associated with improved couple adjustment only in CCT. Reduction in life stress in CCT was associated with a broader range of improvements in CCT compared to TAU. Correlation patterns were substantiated by CCT participants' endorsement of treatment targets emphasizing relationship, communication, emotion, problem solving, addiction and intergenerational issues of trauma. TAU participants reported significantly lower endorsements for these treatment targets. The correlation of ER and couple adjustment suggested as a key process mechanism should be further elucidated in future studies to differentiate relationship-based vs individual-based models and their respective outcomes for primary clients and partners. These findings are considered preliminary, requiring larger samples and advanced modelling among variables to provide a more profound mechanism analysis.