The central feature of misidentification syndromes is the presence of a delusion in which either the identity of the self or other persons is misrecognized. Recent psychiatric case reports have noted the dangerousness posed by persons with misidentification delusions. The authors report on a series of 29 individuals whose delusional misidentification was associated with aggressive behaviors. Im...

Delusions are unfounded yet tenacious beliefs and a symptom of psychotic disorder. Varying degrees of delusional ideation are also found in the healthy population. Here, we empirically validated a neurocognitive model that explains both the formation and the persistence of delusional beliefs in terms of altered perceptual inference. In a combined behavioral and functional neuroimaging study in ...

OBJECTIVE Previous work has suggested that delusions are associated with a higher risk of violence, particularly delusions in which patients believe that people are seeking to harm them or that outside forces are controlling their minds (denoted as "threat/control override" delusions). This study explores the relationship between delusions and violence among patients recently discharged from ac...

BACKGROUND Persecutory delusions may be unfounded threat beliefs maintained by safety-seeking behaviours that prevent disconfirmatory evidence being successfully processed. Use of virtual reality could facilitate new learning. AIMS To test the hypothesis that enabling patients to test the threat predictions of persecutory delusions in virtual reality social environments with the dropping of s...

Ekbom syndrome, also called delusional parasitosis, is a psychiatric disorder characterized by the patient’s conviction that he or she is infested with parasites. Patients with Ekbom syndrome usually seek care from family physicians. We report a case in which the diagnosis of Ekbom syndrome was delayed owing to the presence of bits of spiders in the first sample the patient provided of the inse...

Predominant or specific involvement of the eyes, ears, nostrils, mouth, anus and urethra (the body orifices) has not previously been reported in the literature on delusional parasitosis. Their involvement in the cases reported here is discussed in the context of the Hindu religio-cultural belief system which attaches special significance to these organs in the personal quest for physical, menta...

Two reasoning biases, jumping to conclusions (JTC) and belief inflexibility, have been found to be associated with delusions. We examined these biases and their relationship with delusional conviction in a longitudinal cohort of people with schizophrenia-spectrum psychosis. We hypothesized that JTC, lack of belief flexibility, and delusional conviction would form distinct factors, and that JTC ...

We provide a battery of examples of delusions against which theoretical accounts can be tested. Then we identify neuropsychological anomalies that could produce the unusual experiences that may lead, in turn, to the delusions in our battery. However, we argue against Maher’s view that delusions are false beliefs that arise as normal responses to anomalous experiences. We propose, instead, that ...