The underlying nature of delusions remains unclear despite their importance in psychopathology. Here we present a review of the neurocognitive model of delusions from a cognitive neuroscience viewpoint. There have been numerous reports on cognitive impairments in delusional patients, such as in their reasoning, attention, metacognition, and attribution biases. These findings have been incorporated into several cognitive models that aim to explain the formation, maintenance, and content of delusion. Although delusions are commonly conceptualized as beliefs, not all models make reference to models of normal belief formation. This review focused on two-factor theory models that make a distinction between factors that explain the content of delusions and those that explain their presence. This cognitive theory that includes the 'pragmatic pathology' of delusions can address both the phenomenology and treatment of delusion-related distress.
Bias (Epidemiology) ; Delusions* ; Humans ; Neurosciences ; Psychopathology

Alzheimer's disease (AD) is associated with cognitive and functional impairment as well as neuropsychiatric complications, including psychotic symptoms such as delusions and hallucinations. Recent studies strongly suggest that delusions should be separated from hallucinations. While AD with delusions is a phenotypically distinct from AD without delusions, subtypes of delusions may also define further distinct clinical entities. There has been also considerable debate as to whether delusions in patients with AD differ etiologically, phenomenologically, and therapeutically from delusions in other primary psychiatric illnesses. In other words, whether they are caused by changes to key areas of the brain that have been linked to the presence of delusions. This has led to speculation that these symptoms may respond better to certain drugs such as cholinesterase inhibitors. Integrating the epidemiology, clinical phenomenology, neuropathological and genetic literature for delusions in AD allows us to speculate on pathophysiology and is essential to making progress in the area of delusions in AD.
Alzheimer Disease* ; Brain ; Cholinesterase Inhibitors ; Delusions* ; Epidemiology ; Hallucinations ; Humans

In this transcultural study of schizophrenic delusions among patients in Seoul, Shanghai and Taipei, we discovered that both the frequency and content of delusions differed among the three groups; and that these differences could perhaps be explained by varying sociocultural and political situations. Delusional themes that are sensitive to sociocultural or political situations include guilt, love/sex, religion, somatic damage, economy/business and politics. Delusions regarding longevity, love/sex, dysmorphophobia/dysosmophobia, religion or supernatural matters, and espionage/spy stories were most frequent in Seoul patients. Those in Taipei predominantly had delusions about possession, religion or supernatural matters, hypnotism, and mass media/computers. Shanghai patients often had delusions of poisons, being prickled by poisoned needles, their brain and viscera extracted and being a family member of political authorities.
Adult ; China/epidemiology ; Cross-Cultural Comparison ; Delusions/psychology ; Delusions/epidemiology* ; Female ; Human ; Korea/epidemiology ; Male ; Middle Age ; Prevalence ; Religion ; Schizophrenia/epidemiology* ; Taiwan/epidemiology