Minimal detectable change of the Patient Health Questionnaire-9, Patient Health Questionnaire-8, and Patient Health Questionnaire-2: individual patient data meta-analysis

The authors aimed to estimate the minimal detectable change (MDC) for the Patient Health Questionnaire-9 (PHQ-9), PHQ-8, and PHQ-2, examining variations based on participant and study characteristics. Through an individual participant data meta-analysis involving over 42,000 participants, they found that a six-point difference on the PHQ-9 could serve as an appropriate MDC threshold in general practice, with higher thresholds recommended in specialty mental healthcare settings. The study provides insights into the reliability of these questionnaires for detecting meaningful changes in depression symptoms.