Validation of a novel online depression symptom severity rating scale: the R8 Depression.

ABSTRACT

BACKGROUND: An automated web-based assessment and monitoring system ( www.psynary.com ) has been developed to assist non-specialist clinicians in managing common mood and anxiety disorders. Psynary promotes the use of standardised outcome measures to assess symptom severity and optimise treatments with the aim of improving outcomes and enabling faster recovery. This paper analyses the results from two parallel studies in New Zealand and Japan (OptiMA-1 NZ and Japan) to assess the validity of the R8 Depression scale, one of the system's core outcome measures. METHODS: Clinical samples were recruited from a public secondary care and a private psychiatry clinic. Participants completed the outcome measures for the study via the online Psynary system. The R8 Depression scale is a 30-item questionnaire which includes all symptom domains covered in the ICD-10 classification of depression. The Patient Health Questionnaire (PHQ-9) was completed at the same time points as the R8 Depression, with a smaller sample also completing a paper-based Quick Inventory of Depressive Symptomatology (QIDS-SR16). Internal validity was quantified via Cronbach's alpha and Guttman lower bounds method. External validation against the PHQ-9 and QIDS used the Pearson's and Kendall's correlation coefficients. Severity categories were set using a multivariate regression model. RESULTS: 270 patients participated in the study and completed a maximum of 1 baseline and 5 reviews within a 90-day period, giving a total of 1124 assessments with the PHQ-9 also being completed in 1053 of these assessments. R8 Depression normative data was also collected from 204 non-clinical volunteers with 187 of these also completing the PHQ9. Internal reliability scores were all higher than 0.9 (n = 1328). There was overall good external validity when comparing the R8 Depression to the PHQ-9, with a correlation of 0.91 for the combined normative and clinical samples (n = 1240). CONCLUSIONS: The R8 Depression has been developed as a patient-rated outcome measure for depression for administration on an online system called "Psynary". It has high internal and external validity against current widely used scales. Further work is underway to determine the sensitivity to change of the R8 Depression.