Modular Patient Health Questionnaire (PHQ-9) Adaptations for Symptom-Level and Past-Week Depression Assessment in Clinical and Nonclinical Adults

<p>The Patient Health Questionnaire-9 (PHQ-9) and its shorter forms are widely used measures of depression symptoms. We evaluated three modular adaptations: (1) separating four double-barreled items into eight single-barreled items (sad mood/hopelessness, insomnia/hypersomnia, poor appetite/overeating, and psychomotor agitation/retardation), (2) adding irritability and low libido items, and (3) revising the instructions and response options to assess symptoms over one week rather than two. We tested these adaptations across six studies (N = 2,467). The single-barreled format showed excellent total score and screening classification agreement with the original format, as well as comparable internal consistency, temporal stability, and convergent validity. It also captured greater symptom-level information: the separated items showed stronger correlations with matched criterion measures, distinct endorsement patterns, and non-redundant inter-correlations. The irritability and libido items correlated moderately to strongly with established measures of these constructs. The one-week versions showed moderate-to-strong internal consistency, convergent validity, and temporal stability. We conclude that these adaptations can be adopted individually or together for symptom-level or past-week assessment.</p>