The Collaborative Care Model (CoCM), in which social workers, primary care physicians, and a consulting psychiatrist work as a team, is an established approach to the treatment of common mental health conditions in primary care settings. Following implementation of a CoCM depression care program at our hospital-based academic primary care practice, we observed a low rate of retention with the use of problem solving therapy/behavioral activation (PST/BA). Our aim in this study was to evaluate the effectiveness of interpersonal psychotherapy (IPT), an evidence-based, flexible strategy that focuses on the relationship between depression and interpersonal challenges, compared to PST/BA. In 2015, most patients enrolled in our CoCM received PST/BA. In 2016, most patients received IPT. Patients who were enrolled and discharged from our CoCM depression care program in the years 2015 and 2016 and received either PST/BA or IPT, were included. Our primary measure was the difference in change in PHQ-9 score between the PST/BA and the IPT groups. Secondary outcomes included the difference in the change in GAD-7 score and measures of glycemic and blood pressure control between the two groups. Two hundred thirty four patients were included in our analysis. One hundred sixty five received PST/BA and 69 received IPT. There was no difference between groups in baseline demographics or measures of depression, anxiety, presence of hypertension, or presence of prediabetes/diabetes. Our primary analysis demonstrated a greater decrease in PHQ-9 score in patients receiving IPT (9.93) compared to those receiving PST/BA (5.41) (p < 0.0001). The proportion of patients achieving a clinical response (PHQ-9 < 10) was also greater in the IPT group (71%) compared to the PST/BA group (44%). In a CoCM depression care program, IPT was a more effective strategy in improving depression symptoms as measured by PHQ-9 scores than PST/BA.
Keywords: Anxiety; Collaborative care; Depression; Interpersonal psychotherapy; Primary care.