(PS12-B38) Latent Classes of Symptom Trajectories During Partial Hospitalization for Major Depressive Disorder and Generalized Anxiety Disorder

Several psychotherapies have been empirically validated in the treatment of major depressive disorder (MDD) and generalized anxiety disorder (GAD). Researchers have recently begun to evaluate patient progress in treatment by modeling multiple symptom curves simultaneously, which allows for the identification of differing patient subgroups that progress through treatment on distinct paths. The identification of these trajectories may allow clinicians to predict how a patient will ultimately respond to treatment, based on their symptom trajectory in the initial stages of treatment. Prior research has typically identified two symptom trajectories: (1) responders, who demonstrate steady improvement during treatment, and (2) non-responders, who do not show meaningful improvement. Currently, it is unclear whether this pattern of symptom trajectories occurs within acute treatment settings. The current study used latent growth mixture modeling to identify distinct classes of depression and anxiety symptom trajectories among two separate samples of patients receiving daily partial hospital treatment for MDD or GAD. In addition, this study aimed to identify clinical factors associated with membership in symptom trajectories at baseline and discharge. Data from 1,742 patients were separated by primary diagnosis: a primary MDD sample (n=1512, and a primary GAD sample (n=231). Patients included in analysis were majority female (n=1186, 68.1%) and white (n=1320, 75.8%), with an average age of 37.3. All patients completed measures of depression and anxiety symptoms, coping skills, functioning, positive mental health, and well-being prior to each treatment day. Among the MDD sample, four distinct depression symptom trajectories were identified: responders (n=1024, 67.7%), rapid responders (n=62, 4.1%), early rapid responders (n=55, 3.6%), and minimal responders (n=371, 24.5%). Three of these classes were replicated in the GAD sample: responders (n=79, 34.2%), rapid responders (n=48, 20.8%), and minimal responders (n=104, 45.0%). The identification of responder and minimal responder classes in this sample demonstrate that these are commonly followed symptom trajectories in both outpatient and acute treatment settings. The rapid responder classes in both MDD and GAD samples may be unique to acute treatment settings, as the frequent and intensive nature of treatment may facilitate an upward spiral. In both samples, low symptom severity at baseline was associated with membership in the responder class, though few other patterns emerged in predicting trajectory class membership. At treatment discharge, those in the minimal responder class reported poorer outcomes on every clinical measure, indicating that patients who follow a symptom trajectory that ends in ultimate nonresponse are likely to report negative treatment outcomes in multiple domains. The identification of symptom trajectories may allow clinicians to avoid these negative outcomes by modifying treatment plans for patients who are following a symptom trajectory known to end in ultimate nonresponse.