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PubMed1996

Pathogenesis of schizophrenic delusions and hallucinations: a neural model.

We implement and study a computational model of Stevens' theory of the pathogenesis of schizophrenia. This theory hypothesizes that the onset of schizophrenia is associated with reactive synaptic regeneration in brain regions that receive degenerating temporal lobe projections. Concentrating on one such area, the frontal cortex, we model a frontal module as an associative memory neural network whose input synapses represent incoming temporal projections. Modeling Stevens' hypothesized pathological synaptic changes in this framework results in adverse side effects similar to hallucinations and delusions seen in schizophrenia: spontaneous, stimulus-independent retrieval of stored memories focused on just a few of the stored patterns. These could account for the delusions and hallucinations that occur in schizophrenia without any apparent external trigger and for their tendency to concentrate on a few central cognitive and perceptual themes. The model explains why the positive symptoms of schizophrenia tend to wane as the disease progresses, why delayed therapeutic intervention leads to a much slower response, and why delusions and hallucinations may persist for a long time when they do occur.

Brain↗
PubMedDate not supplied

Long-term evaluation of the effect of quetiapine on hallucinations, delusions and motor function in advanced Parkinson disease.

OBJECTIVES: Mental disorders (MDs) are disabling complications of Parkinson disease (PD). We set out to demonstrate the short- and long-term efficacy of quetiapine, an antipsychotic drug, in controlling hallucinations and delusions in parkinsonian patients without worsening their motor function. Since current guidelines recommend that dopaminergic drugs be decreased or even withdrawn altogether upon the appearance of MDs, we also sought to establish whether quetiapine enables a modification of this common course of action, and hence improve the management of pre-existing motor complications in affected subjects. METHOD: Thirty-five PD patients with disabling MDs were enrolled in this open-label study. Motor function, MDs and cognitive state were evaluated before starting quetiapine therapy and after 1, 3, and 12 months of treatment. RESULTS: MDs significantly improved after 1, 3, and 12 months of quetiapine treatment. At the end of the study the mean daily dose of quetiapine (185 mg) did not produce significant changes in motor or cognitive function. Isolated hallucinations responded to low doses of quetiapine (110 mg daily), while delusions needed 265 mg daily. After 12 months, global dopaminergic therapy was reduced in 3 patients, modified (purely in terms of its components) in 17 patients, and increased in 15 patients. CONCLUSIONS: Quetiapine was effective in the treatment of hallucinations and delusions in PD. It did not worsen motor functions and allowed the dopaminergic treatment in PD patients affected by MDs to be managed safely.

Aged↗
PubMed2003

Internet delusions.

As the use of computers, the Internet, and Internet technology becomes more pervasive in society, psychopathological thought content characterized by the incorporation of the Internet into delusions and hallucinations will become increasingly common. In the following report, three cases of psychotic inpatients are briefly presented to exemplify this trend in pathoplasticity. Interestingly, patients with no real familiarity with the Internet may just as readily incorporate such computer-associated themes into delusional thought patterns. Clinicians should be familiar with the tendency for delusional thoughts to draw from ideas important to society in general. Several interesting points about these cases include the increasing prevalence of Internet delusions, the complete unfamiliarity of two of the patients with the Internet and computers in general, and the tendency for such delusions to be of the controlling, broadcasting, and persecutory types.

Adult↗
PubMed1989

Fictionality of schizophrenic delusions.

A state in which the phenomena of the surrounding world are transformed into a set of symbols that transmit indefinite meanings is thought to provide the circumstances under which delusions arise. The surrounding world is interpreted as a written text, and when the schizophrenic reads this and attempts to construct a coherent fictional account of it, a process of delusion formation takes place, and this process corresponds symptomatologically to a delusional system. If delusions are considered in comparison with fictions, in particular fantastic fictions, areas are found in the paranoid patient's mental processes where contingency is left out, and for that reason it is not possible for the delusional account to be satisfactorily completed.

Adult↗
PubMed1989

The current situation in regard to the delusion of possession in Japan.

A study of possession was made on 1,029 inpatients (male 562, female 467) in Japanese mental hospitals. The results were: (1) The incidence of delusion of possession in the sample was 20.7% for the sample as a whole. (2) As to the contents of delusion of possession, possession by a god was most common. In regard to the difference between the sexes, females were significantly more likely to be possessed by a god than were males. (3) As to the difference between the possession group and the non-possession group, religion, fortuneteller contact, age and diagnosis were significant. (4) As to the characteristics by district in regard to the incidence of delusion of possession, cases of possession were very few in Tokyo and many in Okinawa.

Adult↗
PubMed1997

Subclinical hallucinations and delusions in nonpsychotic adolescents.

A number of studies have suggested that clinical populations of adolescents may report hallucinations and/or delusions without meeting criteria for a psychotic disorder. The purpose of this study was to provide information about the prevalence and symptom correlates of these subclinical hallucinations and delusions that occur in a nonpsychotic population of adolescents. Thirty-eight adolescents from a residential program and day treatment center were assessed with respect to hallucinatory experiences, ideas of reference, paranoid ideation, dissociative experiences, depressive symptomatology, and schizotypal cognitions. Results of this study indicated that 33% of the participants reported having experienced auditory hallucinations, and 24% reported having had delusional ideas. In addition, the results suggest that subclinical auditory hallucinations may have an especially strong relation with dissociative processes, whereas subclinical delusions appeared to be most strongly correlated with schizotypal thought processes. The results of this study begin to clarify the phenomenon of hallucinatory and delusional experiences in a nonpsychotic population.

Adolescent↗
PubMed1984

Frequency and clinical significance of delusions across cultures.

The pattern of delusions in a cross-cultural hospital population was studied. It was found that there were cultural differences in persecutory, grandiose and religious, and sexual and fantastic delusions, accounted for mainly by the relatively higher frequencies in the African and West Indian cultural groups. These phenomena can be understood in terms of the cultural backgrounds of these groups. It is further argued that similarly defined persecutory delusions have a wide clinical significance that goes beyond schizophrenia in some cultural groups.

Africa↗
PubMed1985

Delusions and the psychopathology of the elderly with dementia.

Thirty-seven, out of a sample of 100 elderly subjects, all suffering from dementia, were found to have delusions. The delusions were more common in women, in patients with a history of psychiatric illness, and amongst those with higher information subscores (Blessed Scale); and were less common in patients suffering from apraxia or severe psychosocial incompetence. Amongst the deluded patients the simultaneous presence of disorientation, hallucinations and hyperactivity often signified the diagnosis of delirium, but on follow up it was not correlated with death within 18 months. The same symptoms in the non-deluded patients were correlated with severe social incompetence and death within 18 months. It is concluded that the presence of delusions in subjects over 75 years old suffering from dementia is related, to certain extent, to previous or concomitant psychiatric illness, and that it reflects a relative preservation of mental function amongst those without such history.

Aged↗
PubMed1998

Reasoning biases in delusion-prone individuals.

OBJECTIVES: The objective was to test whether individuals high in delusional ideation exhibit a reasoning bias on tasks involving hypothesis testing and probability judgments. On the basis of previous findings (e.g. Garety, Hemsley & Wessely, 1991), it was predicted that individuals high in delusional ideation would exhibit a 'jump-to-conclusions' style of reasoning and would be less sensitive to the effects of random variation, in comparison to individuals low in delusional ideation. DESIGN: A non-randomized matched groups design was employed enabling the performance of the delusion prone individuals to be compared to that of a control group. METHOD: Forty individuals, selected from the normal population, were divided into groups high and low in delusional ideation, according to their scores on the Peters et al. Delusions Inventory (Peters, Day & Garety, 1996), and were compared on two tasks involving probability judgment and two tasks involving hypothesis testing. RESULTS: Although no significant differences were found on tasks involving hypothesis testing and the aggregation of probabilistic information, it was found that individuals high in delusional ideation had a 'jump-to-conclusions' style of data gathering and were less sensitive to the effects of random variation, in comparison to individuals low in delusional ideation. CONCLUSIONS: In conclusion, although individuals high in delusional ideation were not found to have a general reasoning bias, some evidence of a more specific bias was found. It is thought that these aberrations may play some role in delusion formation in schizophrenia and paranoia.

Adult↗
PubMed1993

Responses to facial and non-facial stimuli presented tachistoscopically in either or both visual fields by patients with the Capgras delusion and paranoid schizophrenics.

An experiment was carried out designed primarily to test A B Joseph's suggestion that patients with Capgras delusion may have problems integrating information between the two cortical hemispheres; and at the same time it was meant to examine J Cutting's ideas linking schizophrenia in general, and the Capgras delusion in particular, to right hemisphere dysfunction. Three patients with the Capgras delusion and three matched controls diagnosed as paranoid schizophrenics were briefly presented pairs of line-drawn object and photographs of faces randomly in the left visual field, the right visual field or bilaterally. The results with objects revealed no particular pattern of performance for either group; but, when faces were shown, the controls revealed the usual left visual field/right hemisphere advantage while for the Capgras group this was reversed. The results are not consistent with a simple prediction from Joseph's hypothesis but they are in accord with Cutting's theory-though they also pose some problems for it, which are discussed.

Adult↗
PubMed1998

Delusion of maternity.

A few case reports on the delusion of pregnancy can be found in the published literature. However, the delusion of maternity, a delusional conviction of the patient that she is a mother of one or more children, has not yet been studied closely. The author describes the case of a 62-year-old childless patient with a diagnosis of chronic paranoid schizophrenia. She developed a delusion of maternity, persistent for many years. This markedly influenced her behaviour.

Delusions↗
PubMedDate not supplied

Old wine in new bottles? Stability and plasticity of the contents of schizophrenic delusions.

A number of recent case reports published during the last 20 years described a quick inclusion of new technologies and cultural innovations into schizophrenic delusions which led many of the authors to the conclusion that the 'Zeitgeist' is creating new delusional contents. On the other hand, long-term comparisons and comparative transcultural studies on delusions showed, despite a certain degree of variability, a stability of delusional themes over longer periods of time. Combining anthropological and historical theories of the development of societies with a differentiated psychopathological approach (Klosterkötter's three-stage model of the formation of schizophrenic delusions), we were able to resolve the problem of the ostensibly divergent results: there are only a few themes of extraordinary anthropological importance for the organization of human relationships which can be found in every epoch and in different cultures (persecution, grandiosity, guilt, religion, hypochondria, jealousy, and love). With the exception of persecution and grandiosity, these themes showed a certain variability over time and between cultures. The 'new' themes, referring to the development of modern technology and the rapid changes of 'cultural patterns' turned out to be only the shaping of the basic delusional themes on the 3rd stage of Klosterkötter's phase model (concretization).

Adult↗
PubMedDate not supplied

Delusion of pregnancy. A case report and review of the literature.

This case report describes the longstanding course of a delusion of pregnancy in a 51-year-old schizophrenic Ghanaian woman suffering from multiple symptoms of delusions and hallucinations. In addition to these symptoms, the patient was affected by multiple coenesthesias, ego disturbances and bizarre delusions of being influenced by external forces. A multi-causal aetiology of delusional pregnancy is discussed.

Delusions↗
PubMed2006

'Mind control' experiences on the internet: implications for the psychiatric diagnosis of delusions.

BACKGROUND: The DSM criteria for a delusion indicate that it should not include any beliefs held by a person's 'culture or subculture'. The internet has many examples of people reporting 'mind control experiences' (MCEs) on self-published web pages, many of which suggest a community based around such beliefs and experiences. It was hypothesized that some of these reports are likely to reflect delusional beliefs and the hyperlinks between web reports were likely to show evidence of social structure, demonstrating the 'culture or subculture' exemption to be increasingly redundant in light of new technology. SAMPLING AND METHODS: Texts from web sites reporting MCEs (n = 10), experience of cancer (n = 10), depression (n = 10) and being stalked (n = 10) were identified, and were blind-rated by three independent psychiatrists for the presence of delusions. Hyperlinks from web sites reporting MCEs were used to create a network structure; this was compared with a size-matched, randomly generated network and known social networks from the literature using social network analysis. CONCLUSIONS: The sampled web-published accounts of MCEs are highly likely to be influenced by delusional beliefs. Social network analysis suggests there is significant evidence of an online community based around these beliefs. The fact that individuals can form a community based on the content of a potentially delusional belief presents a paradox for the DSM diagnostic criteria for a delusion, and suggests the need to revise and revisit the original operational definition in the light of these new technological developments.

Culture↗
PubMed2006

Treatment of delusions in Alzheimer's disease--response to pharmacotherapy.

Delusions are commonly encountered symptoms in patients with Alzheimer's disease and may lead to significant morbidity. The purpose of this article is to review all clinical trials to date focusing on the management of delusions in patients with Alzheimer's disease to determine the level of evidence for treatment. To achieve this objective, Medline was searched using the key words delusions, dementia, Alzheimer's disease and psychosis. Three main categories of treatment were identified: atypical antipsychotics, cholinesterase inhibitors, and other miscellaneous treatments. It was concluded that all forms of treatment were effective although the greatest burden of evidence existed for risperidone and donepezil. Side effects were noted in all forms of treatment and included somnolence and extrapyramidal effects for antipsychotic medications, whereas gastrointestinal effects were more prevalent in studies involving cholinesterase inhibitors. Further large scale, double-blind, randomized, controlled studies are required before a definitive conclusion can be reached. To our knowledge this is the only systematic review of this area.

Aged↗
PubMed1975

A genetic study of chronic delusions.

There is a nosologic difference between the French schizophrenia and the English schizophrenia which include all chronic delusions. A genetic study of chronic delusions, based on the rules of the French nosology, has two goals: two clarify their genetic etiology, and to test those nosologic differences. This study was made on the families of 45 patients with chronic delusions. The conclusions are: the 'délires paranoïaques chroniques' have a genetic etiology and are related to schizophrenia; the 'psychoses hallucinatoires chroniques' are not influenced by the genetic etiology and are not related to schizophrenia. Therefore, the psychoses hallucinatoires chroniques' constitute an autonomic entity according to the French nosology.

Adult↗
PubMed1989

Hallucinations and delusions in 1,715 patients with unipolar and bipolar affective disorders.

The prevalence of hallucinations and delusions was studied in 1,715 patients with unipolar or bipolar affective disorders hospitalized at a tertiary care facility. The authors found that the presence of psychotic features was significantly associated with diagnostic subtype. Bipolar manics were more likely than primary depressives, secondary depressives, and bipolar depressives to have hallucinations and/or delusions; primary depressives were significantly more likely than secondary depressives to have psychotic features. Among psychotic patients, bipolar manics were more likely than the other diagnostic groups to have delusions only and less likely to have hallucinations only. Possible explanations for these findings are discussed.

Bipolar Disorder↗
PubMed1994

Psychodynamic approaches to the Capgras delusion: a critical historical review.

Over the last eight decades a plethora of psychodynamic explanations have been invoked to account for the Capgras delusion. While often ill-founded and convoluted, these formulations have, until recently, dominated many theoretical approaches to the phenomenon. Generally post hoc and teleological in nature, they postulate motives that are not introspectable and defence mechanisms that cannot be observed, measured or refuted. While psychosocial factors can and often do play a part in the development, content and course of the Capgras delusion in individual patients it remains to be proven that such factors are necessary and sufficient to account for delusional misidentification in general and the Capgras delusion in particular.

Capgras Syndrome↗