Published online by Cambridge University Press: 24 May 2017
Recently, a semi-structured interview dedicated to aid rating on the Psychotic Depression Assessment Scale (PDAS) was developed. Here, we aimed to validate PDAS ratings collected via this semi-structured interview.
A total of 50 patients with psychotic depression – 34 with unipolar psychotic depression and 16 with bipolar psychotic depression – were recruited for the study. The following aspects of validity were investigated: clinical validity, psychometric validity (scalability), and responsiveness.
The PDAS ratings were clinically valid (Spearman’s coefficient of correlation between PDAS total scores and Clinical Global Impressions scale – severity of illness ratings=0.66, p<0.001), scalable (Loevinger’s coefficient of heterogeneity at endpoint=0.45), and responsive (no participants met the criterion for remission on the PDAS (total score <8) at baseline – at endpoint 74% (95% CI: 60–85) of the participants met this criterion).
The semi-structured PDAS interview provides valid ratings of the severity of psychotic depression.