Early patterns of symptom change signal remission with interpersonal psychotherapy for depressed adolescents

In the last two decades, substantial progress has been made in the development of efficacious treatments for adolescent depression. However, even when depressed adolescents receive the best treatments delivered under optimal circumstances, 30–50% still do not achieve remission.[3] In practice, this means that clinicians must continually adapt and readapt adolescents’ treatments by sequencing or combining different treatment approaches until remission is reached. With the exception of the TORDIA study which found that adolescents who had not responded to an initial treatment with an SSRI benefitted most from a switch to a different antidepressant and the addition of cognitive behavioral therapy,[4] there are currently no empirically-derived guidelines to direct clinicians in this process. As a consequence, clinicians often implement treatments in a trial and error fashion that could result in extended time to remission, unnecessary experience of side effects, increased cost or other burdens for adolescents and their families, and prolonged use of scarce clinician resources. The development of evidence-based guidelines for personalizing treatments to increase rates of remission and minimize burden has been identified as a public health priority. [5] The goal of this study was to determine whether there are early indicators of acute treatment remission for adolescents with mild to moderate depression treated with 12 sessions of interpersonal psychotherapy (IPT-A) [6] or treatment as usual (TAU) delivered over the course of 16 weeks in school-based health clinics. If it were possible to determine early in treatment whether or not a depressed adolescent is likely to achieve remission by the end of the16 week treatment, this could inform clinicians’ decisions to continue the initial treatment past a certain number of weeks or alter the treatment plan. We focus on early patterns of change in depressive symptoms for two reasons. First, attempts at predicting treatment response from patient demographics or pre-treatment clinical characteristics have yielded mixed results. Most demographic variables have not been found to predict treatment outcome. [7–12] Some studies have found that pre-treatment depression severity and general functioning predict treatment outcome, but the results have not been consistent. [7–9; 11; 12] Second, several previous studies have found early symptom change to predict treatment response. [9; 13–17] A study of cognitive, family, and supportive psychotherapies for adolescent major depressive disorder (MDD) found that adolescents who had demonstrated at least a 50% reduction in self-reported depression symptoms by the second therapy session were significantly more likely to achieve remission at the end of acute treatment and have lower rates of MDD at the 1 year follow-up.[17] Another study found that a 50% reduction in adolescents’ depressive symptoms by week 4 of treatment with fluoxetine predicted remission status at the end of the 12 week treatment.[9] Treatment studies of adult depression have also found that early treatment response predicts treatment outcome, though the time point and criteria for classifying a patient as an early responder have varied.[13; 15; 16] The majority of the studies that examined early prediction of treatment response used pre-determined and non-empirically-derived criteria for categorizing a patient as an early responder (e.g. a patient is an early rapid responder if he or she demonstrates a 50% reduction in symptoms by week 2 [17]). These studies have provided important information about the ability of early symptom reduction to predict acute treatment outcome. However, there is little empirical data to guide clinicians in knowing how much of a reduction is needed and by what time point to evaluate whether remission by the end of acute treatment is likely. In this study, we use the data from an effectiveness study of IPT-A to empirically determine the optimal depression reduction criterion and time point that best predicts remission at the end of 16 weeks of IPT-A and TAU. We also examined the accuracy of baseline levels of depression for predicting remission status since there have been some studies that have found pre-treatment depression severity to be a significant predictor.