(PS14-99) Temporal Dynamics of Well-being and Symptom Severity in Dialectical Behavioral Therapy for Borderline Personality Disorder

Dialectical Behavioral Therapy (DBT) is an evidence-based treatment designed to decrease Borderline Personality Disorder (BPD) symptoms and improve quality of life (Linehan, 1993). Research documents its efficacy in symptom reduction, yet the relationship between DBT and well-being, a component of quality of life, remains underexplored. This study seeks to fill this research gap by examining the temporal sequence of changes in well-being and BPD symptom severity throughout DBT treatment. Data were analyzed from 296 adult and adolescent patients (67% female, 29% male, 3% non-binary or trans-identified, Mage = 28.30 years, SDage = 11.46 years, Range = 11-68 years) enrolled in an outpatient DBT program in Southern California. The Borderline Symptom List-23 (Bohus et al., 2009) and the Mental Health Continuum-Short Form (Keyes, 2009) were administered at intake and 2-month intervals up to 14 months. Linear and nonlinear mixed-effects models were used to examine the trajectory of symptom severity and well-being across treatment. The temporal relationships between well-being and symptom severity across treatment were examined using a cross-lagged panel model. The nonlinear mixed-effects model for BPD symptoms indicated a significant initial decrease (b = -310.65, p < .001) and a subsequent deceleration in change rate (b = 96.38, p < .001). There was a similar trend for well-being, with an initial significant increase (b = 178.22, p < .001) followed by a slower improvement rate (b = -31.61, p < .05). The cross-lagged panel model indicated that early improvements in well-being were significantly associated with later reductions in symptom severity (b = -0.20, p < .05), whereas initial reductions in symptom severity did not significantly relate to later well-being (b = -0.01, p = .79). Observed decreases in symptom severity and increases in well-being across DBT treatment highlight its effectiveness in both reducing BPD symptoms and enhancing elements of quality of life in an outpatient setting. Results indicate that early improvements in well-being may be associated with later reductions in symptom severity, suggesting a potential interplay between well-being and symptom management in DBT. Future research investigating specific DBT components that contribute to both improved well-being and symptom management over time is warranted.