Research & Innovation
Publications
An intensive longitudinal study on interpretation issues with the PHQ instructions
PMU Author
Gunter Schiepek
All Authors
Lennart Seizer, Gunter Schiepek
Journal association
JOURNAL OF AFFECTIVE DISORDERS
Abstract
Concerns have been raised that PHQ-9 instructions ("bothered by" symptoms) conflict with frequency-based response options, potentially leading to some patients experiencing difficulty mapping lived experience onto response options and may conflate frequency with burden. We tested whether weekly PHQ-9 scores aligned more with symptom frequency or burden using an intensive longitudinal design. Depressed patients (n = 23) reported daily symptom presence and burden (n = 1290 days) and completed weekly PHQ-9 (n = 236 weeks). Mixed-effects models decomposed within-and between-person effects and estimated patient-specific frequency-burden weights. Frequency and burden were highly correlated; each predicted PHQ-9 scores when modeled alone, but neither showed unique effects jointly. Thus, weekly PHQ-9 change may reflected a shared symptom-severity signal; person-level heterogeneity was suggested but uncertain. Findings are preliminary and should be interpreted alongside the PHQ-9's strong evidence base.
Keywords
DEPRESSION, Ecological Momentary Assessment, Patient health questionnaire