Heterogeneity in Item Content of Quality of Life Assessments Used in Depression Psychotherapy Research

Quality of life (QOL) broadly encompasses constructs including health, well-being, life satisfaction, and psychosocial functioning. Depression, a major cause of global disability, is linked to lower QOL. Despite the rise of measurement-based care and patient-reported outcomes, there is no consensus on QOL definitions or models, resulting in varied assessments. This study aims to describe the item content overlap among commonly used QOL measures in depression research. We analyzed 10 QOL measures from a meta-analysis, calculating Jaccard indices to quantify overlap, and used two coding approaches: one for similarly worded items and another for exact word matches. We also categorized items into broader themes. At the most, average Jaccard similarity was <i>M</i> = 0.14 (SD = 0.12), indicating significant heterogeneity among QOL measures in depression. This suggests that QOL outcomes may not be reproducible across different scales. Future research should examine the relationships between the content assessed by various QOL measures.