Magnetic resonance imaging findings in patients with delusional disorder due to diffuse cerebrovascular disease: a report of seven cases

Regional gray matter volume and structural network strength in somatic vs. non-somatic delusional disorders

BACKGROUND

Monothematic delusional disorders are characterized by a single tenacious belief. They provide a great opportunity to study underlying brain structures in the absence of confounding symptoms that accompany delusions in schizophrenia. Delusional beliefs include persecution, jealousy or somatic delusions including infestation. It is unclear whether specific delusional content is associated with distinct neural substrates.

METHODS

We used magnetic resonance imaging in patients presenting with somatic vs. non-somatic delusional disorders. Patients with delusional infestation (DI, n=18), and individuals with non-somatic delusional disorders (n=19) were included, together with healthy volunteers (n=20). Uni- and multivariate techniques for structural data analysis were applied to provide a comprehensive characterization of abnormal brain volume at both the regional and neural network level.

RESULTS

Patients with DI showed lower gray matter volume in thalamic, striatal (putamen), insular and medial prefrontal brain regions in contrast to non-somatic delusional disorders and healthy controls. Importantly, these differences were consistently detected at regional and network level. Compared to healthy controls, patients with delusional disorders other than DI showed lower gray matter volume in temporal cortical regions.

CONCLUSION

The data support the notion that dysfunctional somatosensory and peripersonal networks could mediate somatic delusions in patients with DI in contrast to delusional disorders without somatic content. The data also suggest putative content-specific neural signatures in delusional disorders and in delusion formation per se.

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

AIMS

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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

A general neuropsychological model of delusion

INTRODUCTION

Neurocognitive accounts of delusion have traditionally highlighted perceptual misrepresentation, as the primary trigger in addition to other cognitive deficits that maintain the delusion. Here, a general neurocognitive model of delusional disorder (DSM-IV) is proposed, not so much based on perceptual or cognitive deficits after right hemisphere damage as on cognitive propensities, specifically excessive inferencing (especially jumping to conclusions) and excessive reference to the self, due to left hemisphere overactivity.

METHOD

The functional imaging, topographic EEG, and experimental imaging literatures on delusional disorder are reviewed, and 37 previously published cases of postunilateral lesion delusion (DSM-IV type, grandeur, persecution, jealousy, erotomania, or somatic), are reviewed and analysed multivariately.

RESULTS

Functional imaging and EEG topography data were slightly more indicative of left hemisphere overactivity in delusional disorder. In addition, 73% of the postunilateral lesion cases (χ(2)=7.8, p=.005) of delusional disorder (DSM-IV type) had a right hemisphere lesion, whereas only 27% had a left hemisphere lesion.

CONCLUSION

Left hemisphere release appears to be a more primary cause of delusional disorder than right hemisphere impairment, the latter merely entailing loss of inhibition of delusional beliefs. We propose that most patients with DSM-IV diagnoses of delusional disorder could be afflicted by excessive left hemisphere activity, but further research is necessary.

Delirium in acute stroke

Delirium is the presenting feature in a few stroke patients, but can complicate the clinical course of acute stroke in up to 48% of cases. Old age, extensive motor impairment, previous cognitive decline, metabolic and infectious complications, and sleep apnoea are all predisposing conditions for delirium. Patients with delirium have longer hospitalizations and a poorer prognosis, and are at increased risk of developing dementia. The identification of the patients at risk and non-pharmacological preventative interventions are the key measures in the management of delirium.