Literature Collection

Depression symptom measurement instruments such as PHQ-9, HADS and BDI are used to aid in the diagnosis and management of depression. Variation in within-individual depression symptom measurements may affect their clinical utility but estimates of this variation are currently almost non-existent. Data on PHQ-9, HADS and BDI results and sociodemographic, lifestyle and comorbidity covariates were extracted from the CPRD database. A minimum of four measurements in the same individual was the only inclusion criterion. Within-individual measured variation was calculated as a coefficient of variation (CV) using a linear regression random effects model. RESULTS: 195,171 participants had at least four measures of PHQ-9 after impossible values were excluded. For HADS, this figure was 8231 participants and for BDI 215, making this by far the largest study of variation of depression symptom measurement instruments to date. The overall total coefficient of variation (CV(T)) (95% confidence interval) was 0.412 (0.411 to 0.413) for PHQ-9, 0.370 (0.365 to 0.374) for HADS and 0.763 (0.701 to 0.826) for BDI. In contrast to studies of variation of other tests, variation decreased with increased mean patient score (i.e. variation decreased with worsening disease severity). Estimated within-individual variation in this analysis of real-world data is very high and has not previously been reported. Variation decreases with patient mean score. The high within-individual variation of depression measurement instruments and the higher estimated variation in less severely affected patients have important implications for the diagnosis, monitoring and clinical decision-making for depression.

PURPOSE OF REVIEW: We review recent literature on the adaptive assessment of complex mental health disorders and provide a detailed comparison of classical test theory and adaptive testing based on multidimensional item response theory. RECENT FINDINGS: Adaptive tests for a wide variety of mental health traits (e.g., depression, anxiety, mania, substance misuse, suicidality) are now available in a cloud-based environment. These tests have been validated in a variety of settings against lengthy structured clinical interviews with excellent results and even higher reliability than fixed-length tests. Applications include screening and assessments in emergency departments, psychiatric and primary care clinics, student health clinics, perinatal medicine clinics, child welfare settings, and the judicial system. The future of mental health measurement will be based on automated screening and assessments. Adaptive tests will provide increased precision of measurement and decreased burden of measurement. Integration into the electronic health record is important and now easily accomplished.