(PS1-85) Bidirectional Associations Between Physical Health-related Quality of Life and Depression in an App-based Intervention for Major Depressive Disorder

Abstract Text:

Background: Research suggests a bidirectional relationship between physical health and depression symptoms. Depression is linked to an increased risk of chronic conditions, while poor physical health can increase depression risk. Physical health-related quality of life (HRQoLphys) reflects an individual’s perceived physical well-being, including factors such as mobility, pain, energy, and sleep quality. Although HRQoLphys is influenced by objective physical health, it also encompasses subjective perceptions of health and functioning. In depressed individuals, these perceptions may be cognitively distorted and exacerbated by their depression. Given the complex interplay between depression and physical health, it is essential to consider both mental and physical symptoms in depression treatment. The current study examines the bidirectional relationship between HRQoLphys and depression in the context of an 8-week study examining the effectiveness of a mobile app for depression designed to facilitate thought progression.

Methods: 101 participants with mild-to-moderate Major Depressive Disorder (MDD) were randomized to either the treatment (n= 74) or the waitlist control group (n=27), stratified to control for gender identity. Participants (Mage = 33.01, SD = 8.53, range= 20–50) were predominantly female (77.8%) and White (61.5%). Participants completed the physical health subscale of the World Health Organization Quality of Life scale (WHOQOL-BREF) at baseline, week 4, and week 8 to assess self-reported HRQoLphys. Subjects also completed the Patient Health Questionnaire (PHQ-9) daily to evaluate their depression levels. The treatment group was instructed to use the app for at least 15 minutes per day, 4 days per week, over the 8-week study. Pearson correlation assessed the relationship between HRQoLphys and depression at baseline. Mediation analysis tested whether changes in HRQoLphys from baseline to week 8 mediated changes in depression based on treatment condition. A second mediation analysis examined the reverse direction, testing whether reductions in depression symptoms mediated improvements in HRQoLphys.

Results: HRQoLphys and depression were moderately correlated at baseline (r= -0.33, p< 0.001). Mediation analysis revealed that the app had a significant indirect effect on depression through HRQoLphys (ß=1.65, SE=0.80, p=0.04). Another mediation analysis revealed that the app indirectly improved HRQoLphys through reductions in depression (ß=1.50, SE=0.52, p=0.04). Participants in the intervention group improved by 1.65 points in depression and 1.50 points in HRQoLphys, compared to the waitlist control group.

Conclusion: Consistent with previous findings, these results suggest that patients with more severe depression tend to report lower HRQoLphys. Moreover, the intervention group experienced greater improvements in depression than the waitlist control group through enhancing HRQoLphys, and conversely, reductions in depression also contributed to improvements in HRQoLphys. These results underscore the bidirectional relationship between physical health-related quality of life and depression, suggesting that targeting either domain may contribute to overall treatment efficacy.