Identifying subgroups with differential response to CBASP versus Escitalopram during the first eight weeks of treatment in outpatients with persistent depressive disorder

There exists little empirical evidence helping clinicians to select the most effective treatment for individual patients with persistent depressive disorder (PDD). This study identifies and characterizes subgroups of patients with PDD who are likely to benefit more from an acute treatment with psychotherapy than from pharmacotherapy and vice versa. Non-medicated outpatients with PDD were randomized to eight weeks of acute treatment with the Cognitive Behavioral Analysis System of Psychotherapy (CBASP; n = 29) or escitalopram plus clinical management (ESC/CM; n = 31). We combined several baseline variables to one composite moderator and identified two subgroups of patients: for 56.0%, ESC/CM was associated with a greater reduction in depression severity than CBASP, for the remaining 44.0%, it was the other way around. Patients likely to benefit more from ESC/CM were more often female, had higher rates of moderate-to-severe childhood trauma, more adverse life events and more previous suicide attempts. Patients likely to benefit more from CBASP were older, had more often an early illness onset and more previous treatments with antidepressants. Symptomatic response, remission, and reductions in symptom severity occurred more often in those patients treated with their likely more effective treatment condition. The findings suggest that the baseline phenotype of patients with PDD moderates their benefit from acute treatment with CBASP relative to ESC/CM. Once confirmed in an independent sample, these results could serve to guide the choice between primarily psychotherapeutic or pharmacological treatments for outpatients with PDD.