Delusional disorders are a naturally occurring 'experimental psychosis'

Understanding delusions

Delusion has always been a central topic for psychiatric research with regard to etiology, pathogenesis, diagnosis, treatment, and forensic relevance. The various theories and explanations for delusion formation are reviewed. The etiology, classification and management of delusions are briefly discussed. Recent advances in the field are reviewed.

Delusion in general and forensic psychiatry--historical and contemporary aspects

Delusion has always been a central topic for psychiatric research with regard to etiology and pathogenesis and to diagnosis, treatment, and forensic relevance. Throughout the history of psychiatry as a scientific discipline, there has been dissent on the issue of whether chronic delusion is a nosological entity of its own or just a specific type of another mental disorder, e.g. schizophrenia, mania, or personality disorder, and there already is a considerable literature on this. This article seeks to elucidate the central lines of thought that have governed the scientific debate on delusions and delusion-associated phenomena since the early 19th century. Special attention is given to the practical relevance of these theoretical considerations for forensic questions and psychiatric research. Due to the complex features of delusions, research in this area may well become paradigmatic for many other complicated psycho(patho)logical phenomena, e.g. consciousness, hallucinations and psychotic depression.

A study of HLA-linked genes in a monosymptomatic psychotic disorder in an Indian Bengali population

OBJECTIVE

The etiology of delusional disorder is imperfectly understood. Involvement of biological factors has long been suspected. We examined the incidence of class I human leukocyte antigens (HLAs) in patients with delusional disorder to understand the role of HLA genes and explore a possible immunogenetic etiology for delusional disorder.

METHODS

We used a nested case-control study design. Psychiatric reference data were available for 27 500 patients registered between 1998 and 2003. Initially, we enrolled 150 patients with delusional disorder from the India-born Bengali population, using DSM-IV diagnostic criteria. After longitudinal follow-up, 80 patients were found to have only delusional disorder, while the remaining 70 patients represented different illnesses with paranoid symptoms and were excluded. We performed serological typing on all 150 patients and applied the polymerase chain reaction-based high-resolution molecular typing method to the 80 patients with delusional disorder. Eighty healthy donors of the same ethnic background, matched for age, sex, and other socioeconomic variables, formed the control group.

RESULTS

Some of the HLA alleles were associated with delusional disorder, and the gene HLA-A*03 was found to be significantly more frequent. This gene may influence patients' susceptibility to delusional disorder.

CONCLUSION

The study reveals important associations between HLA genes and delusional disorder. This preliminary observation may help our understanding of this disorder's genetic basis.