Empirical redefinition of delusional disorder and its phenomenology: the DELIREMP study

Since Kraepelin, the controversy has persisted surrounding the nature of delusional disorder (DD) as a separate nosological entity or its clinical subtypes. Nevertheless, there has been no systematic study of its psychopathological structure based on patient interviews. Our goal was to empirically explore syndromic subentities in DD.

A cross-sectional study was conducted in 86 outpatients with DSM-IV-confirmed DD using SCID-I. Psychopathological factors were identified by factor analysis of PANSS scores. The association between these factors and clinical variables (as per standardized instruments) was analyzed using uni- and multivariate techniques.

PANSS symptoms were consistent with four factors (Paranoid, Cognitive, Schizoid, and Affective dimensions), accounting for 59.4% of the total variance. The Paranoid Dimension was associated with premorbid paranoid personality disorder, more adverse childhood experiences, chronic course, legal problems, worse global functioning, and poorer treatment adherence and response. The Cognitive Dimension was associated with poorer cognitive functioning, premorbid substance abuse, comorbid somatic diseases, mainly non-prominent visual hallucinations, fewer comorbid depressive disorders, and poorer global functioning. The Schizoid Dimension was associated with being single, a family history of schizophrenia, premorbid personality disorders (largely schizoid and schizotypal), non-prominent auditory hallucinations, and dysthymia. Finally, the Affective Dimension was associated with a family history of depression, premorbid obsessive personality, somatic delusions, absence of reference delusions, tactile and olfactory hallucinations, depressive and anxiety disorders, risk of suicide, and higher perceived stress.

The identification and clinical validation of four separate psychopathological dimensions in DD provide evidence toward a more accurate conceptualization of DD and its types.