Psychometric instruments for the assessment of depressive symptoms in patients with delusional disorder: A systematic review

Patients with delusional disorder (DD) are at an increased risk for the development of depressive symptoms. We aimed to examine the literature dealing with assessment tools to assess depressive symptoms in DD. A systematic review was performed by searching PubMed, Scopus and clinicaltrials.gov databases from inception until June 2021 (PRISMA guidelines). From 1863 initial retrieved records, 11 studies were included (N = 715 DD patients). Depressive comorbidity ranged from 20.9% to 53.5%. Seven studies used semistructured/structured interviews: OPCRIT 4.0 (n = 1), Manual for Assessment and Documentation of Psychopathology in Psychiatry (AMDP System) (n = 2), the MINI interview (n = 1), DSM-IV (n = 1), ICD-10 (n = 1); and the Diagnostic Interview Schedule (DIS-R) (n = 1). Seven studies used at least one observer-rated scale: Positive and Negative Syndrome Scale (PANSS)-depressive component (n = 2), Hamilton Rating Scale for Depression (HRSD, n = 3), Montgomery-Asberg Depression Rating Scale (MADRS, n = 1), Clinical Global Impression Scale (CGI, n = 1) and the Bipolar Affective Disorder Dimension Scale (BADDS, n = 1). Assessment scales administered in depressive disorders and schizophrenia are applied to DD. This is the first systematic review exploring the use of assessment tools for depressive symptoms in DD. The use of the MADRS to assess depressive symptoms can be recommended in combination with other clinical scales, for instance, the CGI.