Psychotic experiences in childhood are associated with increased structural integrity of the left arcuate fasciculus - A population-based case-control study

Around 1 in 5 children under 13 years old experience sub-clinical psychotic experiences (PEs) like hallucinations and delusions. While PEs in childhood are a significant risk factor for adult psychotic disorders, the majority of those experiencing childhood PEs do not develop a psychotic disorder. Individual differences in regional brain maturation rates may be responsible for this age-related and often transient emergence of PEs. Fronto-temporal association tracts undergo extensive maturation and myelination throughout childhood and adolescence, thus we focus on individual differences in one such tract, the arcuate fasciculus. A normative population-based sample of children (aged 11-13) attended a clinical interview and MRI (n = 100), 25 of whom were identified as reporting strong PEs. This group had reduced mean and radial diffusivity in the arcuate fasciculus compared with a group of matched controls (n = 25) who reported no PEs. The group difference was greater in the left hemisphere than the right. Mediation analyses showed that this group difference was driven predominantly by perceptual disturbances and an along-tract analysis showed that the group difference was greatest approximately halfway between the frontal and temporal termination points of the tract (adjacent to the left lateral ventricle). This study is the first to investigate links between arcuate fasciculus diffusivity and psychotic experiences in a population sample of children.

Aberrant myelination of the cingulum and Schneiderian delusions in schizophrenia: a 7T magnetization transfer study

BACKGROUND

The structural integrity of the anterior cingulum has been repeatedly observed to be abnormal in patients with schizophrenia. More recently, aberrant myelination of frontal fasciculi, especially, cingulum has been proposed to underlie delayed corollary discharges that can affect sense of agency and contribute to delusions of control (Schneiderian delusions). Using the magnetization transfer phenomenon at an ultra-high field 7T MRI, we investigated the putative myelin content of cingulum bundle in patients with schizophrenia.

METHODS

Seventeen clinically stable patients with schizophrenia and 20 controls were recruited for this 7T MRI study. We used a region-of-interest method and extracted magnetization transfer ratio (MTR) from left and right dorsal cingulum bundles and estimated patients v. controls differences. We also related the cingulum MTR values to the severity of Schneiderian delusions.

RESULTS

Patients had a significant reduction in the MTR, indicating reduced myelin content, in the cingulum bundle (right cingulum Hedges' g = 0.91; left cingulum g = 0.03). The reduced MTR of left cingulum was associated with higher severity of Schneiderian delusions (τ = -0.45, p = 0.026) but no such relationship was seen for the right cingulum MTR (τ = -0.136, p = 0.50) among patients. The association between the left cingulum MTR and Schneiderian delusions was not explained by the presence of other delusions, hallucinations, disorganization or negative symptoms.

CONCLUSIONS

Dysmyelination of the cingulum bundle is seen in a subgroup of patients with schizophrenia and may be involved in the mechanism of Schneiderian delusions.

Gray Matter Changes Associated With the Development of Delusions in Alzheimer Disease

OBJECTIVE

Delusions affect approximately a third of Alzheimer disease (AD) patients and are associated with poor outcomes. Previous studies investigating the neuroanatomic correlates of delusions have yet to reach a consensus, with findings of reduced volume across all lobes, particularly in frontal regions. The current study examined the gray matter (GM) differences associated with delusions in AD.

METHODS

Using voxel-based morphometry, we assessed GM in 23 AD patients who developed delusions (AD+D) and 36 comparable AD patients who did not (AD-D) at baseline and follow-up. Analysis of variance was used to identify consistent differences between AD+D and AD-D patients across time points (main effect of group), consistent changes from baseline to follow-up (main effect of time), and differential changes between AD+D and AD-D over time (interaction of group and time). All data were obtained from the National Alzheimer's Coordinating Center database.

RESULTS

The AD+D group had consistently lower frontal GM volume, although both groups showed decreased GM in frontotemporal brain regions over time. An interaction was observed between delusions and longitudinal change, with AD+D patients having significantly elevated GM in predominantly temporal areas at baseline assessment, becoming significantly lower than the AD-D group at follow-up.

CONCLUSION

These findings suggest that, there are specific volumetric markers that distinguish patients with delusions from those without, before, and after the onset of delusions. Specifically, the decline of GM in temporal areas that had elevated levels prior to the onset of delusions may be involved in the manifestation of delusions.

Network localization of heterogeneous neuroimaging findings

Studies of the same disease often implicate different brain regions, contributing to a perceived reproducibility crisis in neuroimaging. Here, we leverage the normative human brain connectome to test whether seemingly heterogeneous neuroimaging findings localize to connected brain networks. We use neurodegenerative disease, and specifically Alzheimer's disease, as our example as it is one of the diseases that has been studied the most using neuroimaging. First, we show that neuroimaging findings in Alzheimer's disease occur in different brain regions across different studies but localize to the same functionally connected brain network. Second, we show that neuroimaging findings across different neurodegenerative diseases (Alzheimer's disease, frontotemporal dementia, corticobasal syndrome, and progressive non-fluent aphasia) localize to different disease-specific brain networks. Finally, we show that neuroimaging findings for a specific symptom within a disease (delusions in Alzheimer's disease) localize to a symptom-specific brain network. Our results suggest that neuroimaging studies that appear poorly reproducible may identify different regions within the same connected brain network. Human connectome data can be used to link heterogeneous neuroimaging findings to common neuroanatomy, improving localization of neuropsychiatric diseases and symptoms.

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.

Association Between Psychosis Phenotype and APOE Genotype on the Clinical Profiles of Alzheimer's Disease

BACKGROUND

Psychosis is a common phenomenon in Alzheimer's disease (AD). The APOE ε4 allele is the strongest genetic risk factor for the development of AD, but its association with psychosis remains unclear.

OBJECTIVE

We investigated the associations between psychosis, subdivided into delusions and hallucinations, as well as APOE ε4 allele on cognitive and functional outcomes. Secondarily, we investigated the associations between APOE ε4, Lewy bodies, and psychosis.

METHODS

Data from the National Alzheimer's Coordinating Center (NACC) were used. Nine hundred patients with a confirmed diagnosis of AD based on the NIA-AA Reagan were included in the analysis. Global cognition was assessed using the Mini-Mental State Exam (MMSE) and functional status was assessed using the Functional Activities Questionnaire (FAQ). Psychosis status was determined using the Neuropsychiatric Inventory Questionnaire (NPI-Q). Factorial design was used to assess the effects of psychosis and APOE ε4, as well as their interaction.

RESULTS

Psychosis and the presence of APOE ε4 were both associated with lower MMSE scores, while only psychosis was associated with higher FAQ scores. Furthermore, patients with hallucinations had lower MMSE and higher FAQ scores than patients with only delusions. There was a significant interaction effect between psychosis and APOE ε4 on MMSE scores, with APOE ε4 negatively affecting patients with hallucinations-only psychosis. APOE ε4 was positively associated with the presence of Lewy body pathology, and both were found to be more prevalent in psychotic patients, with a stronger association with hallucinations.

CONCLUSION

Psychosis in AD was associated with greater cognitive and functional impairments. Patients with hallucinations-with or without delusions-conferred even greater deficits compared to patients with only delusions. The APOE ε4 allele was associated with worse cognition, especially for patients with hallucination-only psychosis. APOE ε4 may mediate cognitive impairment in the hallucinations phenotype through the development of Lewy bodies. Our findings support that subtypes of psychosis should be evaluated separately.

Capgras Syndrome and Other Delusional Misidentification Syndromes

The delusional misidentification syndromes (DMS) are a group of disorders, characterized by patients mistaking the identity of people they know, although they recognize them physically. The term DMS is an umbrella term which may cover disorders whose definition extends to objects other than people, such as animals, places, or familiar material objects. The most common and best known DMS is Capgras syndrome. In this disorder, the misidentification leads to the delusional conviction that a close friend or relative has been replaced by an identical - or almost identical - "double," whose original has disappeared. This double is an imposter without name or identity. Most often considered as a persecutor, the double may be subjected to aggression, which may be very violent. Neuropsychological hypotheses based on cerebral dysfunctions are now commonly considered to be at the origin of the disorder. They have been elaborated from achievements in the neurosciences, particularly the facial recognition models. In return, knowledge about the normal cognitive processes involved in recognition and familiarity has benefited from the work that cognitive neuropsychiatry has invested in these disorders. The DMS are observed in various contexts of morbidity: primary psychiatric diagnosis, or secondary to various organic disorders, particularly in neurodegenerative disease; they are rarely met in isolated form. Most often, they develop in line with the associated pathology. In the absence of consensual clinical description, the epidemiology of DMS is uncertain; they may be more frequent than previously supposed. There is no specific treatment for these disorders; neuroleptics are generally used in association with treatment of the concomitant disorder. The frequent association of DMS with organic disorders which may be curable and the particularly dangerous profile of these patients are factors that underline the need for better screening.

Decreased gray matter volume is associated with the subtypes of psychotic symptoms in patients with antipsychotic-naïve mild or moderate Alzheimer's disease: A voxel-based morphometry study

The purpose of this study was to investigate the association between brain regional gray matter volume and two subtypes of psychotic symptoms, namely paranoid and misidentification subtypes, in antipsychotic-naïve mild or moderate Alzheimer's disease (AD) patients. Forty AD patients with psychotic symptoms and 25 AD patients without psychotic symptoms were assessed for cognitive and functional impairment. Presence and subtype of psychotic symptoms were assessed by using the delusion and hallucination subscale of the Korean Neuropsychiatric Inventory (K-NPI). Structural MRI images were acquired on a 3 T scanner, and were analyzed using voxel-based morphometry (VBM) for automated analysis. The misidentification subtype is associated with more severe gray matter atrophy, and paranoid subtype is associated with less severe gray matter atrophy compared to non-psychosis group. These results suggest that the misidentification, the paranoid subtype and the non-psychosis group have a distinct neural correlation.

Testing the connections within face processing circuitry in Capgras delusion with diffusion imaging tractography

Although Capgras delusion (CD) patients are capable of recognizing familiar faces, they present a delusional belief that some relatives have been replaced by impostors. CD has been explained as a selective disruption of a pathway processing affective values of familiar faces. To test the integrity of connections within face processing circuitry, diffusion tensor imaging was performed in a CD patient and 10 age-matched controls. Voxel-based morphometry indicated gray matter damage in right frontal areas. Tractography was used to examine two important tracts of the face processing circuitry: the inferior fronto-occipital fasciculus (IFOF) and the inferior longitudinal (ILF). The superior longitudinal fasciculus (SLF) and commissural tracts were also assessed. CD patient did not differ from controls in the commissural fibers, or the SLF. Right and left ILF, and right IFOF were also equivalent to those of controls. However, the left IFOF was significantly reduced respect to controls, also showing a significant dissociation with the ILF, which represents a selective impairment in the fiber-tract connecting occipital and frontal areas. This suggests a possible involvement of the IFOF in affective processing of faces in typical observers and in covert recognition in some cases with prosopagnosia.

Gray matter atrophy in patients with mild cognitive impairment/Alzheimer's disease over the course of developing delusions

OBJECTIVE

We conducted a neuroimaging analysis to understand the neuroanatomical correlates of gray matter loss in a group of mild cognitive impairment and early Alzheimer's disease patients who developed delusions.

METHODS

With data collected as part of the Alzheimer's Disease Neuroimaging Initiative, we conducted voxel-based morphometry to determine areas of gray matter change in the same Alzheimer's Disease Neuroimaging Initiative participants, before and after they developed delusions.

RESULTS

We identified 14 voxel clusters with significant gray matter decrease in patient scans post-delusional onset, correcting for multiple comparisons (false discovery rate, p < 0.05). Major areas of difference included the right and left insulae, left precuneus, the right and left cerebellar culmen, the left superior temporal gyrus, the right posterior cingulate, the right thalamus, and the left parahippocampal gyrus.

CONCLUSIONS

Although contrary to our initial predictions of enhanced right frontal atrophy, our preliminary work identifies several neuroanatomical areas, including the cerebellum and left posterior hemisphere, which may be involved in delusional development in these patients.

Correlation between right medial temporal lobe atrophy and persecutory delusions in patients with dementia of the Alzheimer's type demonstrated on VSRAD advance

BACKGROUND

The relationship between focal brain atrophy and delusions in patients with Dementia of the Alzheimer's Type (DAT) is not well understood. Few studies have been reported on the association between medial temporal atrophy (MTA) and persecutory delusions in patients with DAT. We investigated the relationship between MTA and persecutory delusions in patients with DAT using voxel-based specific regional analysis system for Alzheimer's disease (VSRAD) advance software, which allows us to quantify the laterality and the degree of MTA on magnetic resonance imaging (MRI) scans.

METHODS

Thirty-one patients diagnosed with DAT were recruited and scanned with a 1.5 tesla MRI scanner. All MRI data were analyzed using VSRAD advance. The target volume of interest (VOI) included the entire region of the entorhinal cortex, hippocampus, and amygdala. The degree of MTA was obtained from the averaged positive z score (Z-score) on the target VOI, with higher scores indicating more severe. These DAT patients were divided into a group with (D group: n = 13) and without (ND group: n = 18) persecutory delusions.

RESULTS

In the D group, the mean the bilateral, right, and left Z-scores were 2.45, 2.69, and 2.19, respectively. These mean Z-scores of the ND group were 2.00, 2.00, and 1.95, respectively. The right Z-scores for the D group were significantly higher than those for the ND group (p < 0.05).

CONCLUSIONS

These findings suggest that right MTA could contribute to the development of persecutory delusions in patients with DAT.

[Delusional disorder, autoaggression und suicide]

The authors report on the suicide of a 27-year-old woman with extreme self-inflicted injuries. The victim suffered from schizophrenic psychosis with several stays in mental institutions and one previous suicide attempt. Autopsy revealed multiple cut and stab injuries in various body regions (51 stabs to the chest, cutting off parts of ears and nose, stab to the eye and transection of the scalp). Death was caused by exsanguination.

The neurobiology of schizotypy: fronto-striatal prediction error signal correlates with delusion-like beliefs in healthy people

Healthy people sometimes report experiences and beliefs that are strikingly similar to the symptoms of psychosis in their bizarreness and the apparent lack of evidence supporting them. An important question is whether this represents merely a superficial resemblance or whether there is a genuine and deep similarity indicating, as some have suggested, a continuum between odd but healthy beliefs and the symptoms of psychotic illness. We sought to shed light on this question by determining whether the neural marker for prediction error - previously shown to be altered in early psychosis--is comparably altered in healthy individuals reporting schizotypal experiences and beliefs. We showed that non-clinical schizotypal experiences were significantly correlated with aberrant frontal and striatal prediction error signal. This correlation related to the distress associated with the beliefs. Given our previous observations that patients with first episode psychosis show altered neural responses to prediction error and that this alteration, in turn, relates to the severity of their delusional ideation, our results provide novel evidence in support of the view that schizotypy relates to psychosis at more than just a superficial descriptive level. However, the picture is a complex one in which the experiences, though associated with altered striatal responding, may provoke distress but may nonetheless be explained away, while an additional alteration in frontal cortical responding may allow the beliefs to become more delusion-like: intrusive and distressing.

Attributional style in a case of Cotard delusion

Young and colleagues (e.g. Young, A. W., & Leafhead, K. M. (1996). Betwixt life and death: case studies of the Cotard delusion. In P. W. Halligan & J. C. Marshall (Eds.), Method in madness: Case studies in cognitive neuropsychiatry. Mahway, NJ: Lawrence Erlbaum Associates.) have suggested that cases of the Cotard delusion (the belief that one is dead) result when a particular perceptual anomaly (caused by a disruption to the affective component of visual recognition) occurs in the context of an internalising attributional style. This hypothesis has not previously been tested directly. We report here an investigation of attributional style in a 24-year-old woman with Cotard delusion ("LU"). LU's attributional style (and that of ten healthy control participants) was assessed using the Internal, Personal and Situational Attributions Questionnaire (Kinderman, P., & Bentall, R. P. (1996). A new measure of causal locus: the internal, personal and situational attributions questionnaire. Personality and Individual Differences, 20(2), 261-264.). LU showed a significantly greater proportion of internalising attributions than the control group, both overall and for negative events specifically. The results obtained thus support an association of Cotard delusion with an internalising attributional style, and are therefore consistent with the account of Young and colleagues. The potential brain basis of Cotard delusion is discussed.

On a peculiar environmental dependency syndrome in a case with frontal-temporal damage: Zelig-like syndrome

We report on the case of a patient with frontal-temporal damage from cerebral hypoxia, affected by amnesic disturbances and behaviour disorder, who presented a peculiar phenomenon of environmental dependency. He assumed a different social role in keeping with different environmental circumstances by interpreting a character corresponding to the particular context. Three experiments were carried out in which the environmental variables were manipulated to verify the phenomenon in controlled conditions, and an investigation was conducted during the patient's spontaneous manifestations. The phenomenon was interpreted as a loss of frontal inhibition whose function was the control of his own identity and consequent "attraction" towards a social role proposed by the environment.

Hippocampal abnormalities and memory deficits: new evidence of a strong pathophysiological link in schizophrenia

The central goals of this manuscript are (1) to better characterize what appears to be the most parsimonious account of schizophrenic long-term memory impairment in the neuropsychological literature: a contextual binding deficit rooted in the medial temporal lobes; (2) to link this deficit to concrete abnormalities at the level of the hippocampus; and (3) to suggest that this deficit could lead to the functional impairment experienced by schizophrenia patients in their daily lives. As far as long-term memory is concerned in schizophrenia, there seems to be a general agreement to conclude that explicit mechanisms are disturbed compared to relatively spared implicit mechanisms. More precisely, both subsystems of explicit memory (i.e., episodic and semantic) appear to be dysfunctional in this patient population. Errors during the encoding processes could be responsible for this dysfunction even if retrieval per se is not totally spared. Recently, a number of studies have suggested that impairments in conscious recollection and contextual binding are closely linked to episodic memory deficit. Since the hippocampal formation is considered to be the central element in the neural support for contextual binding and episodic memory, we have conducted an extensive review of the literature concerning the hippocampal formation in schizophrenia. Emerging evidence from varying disciplines confirm the coherence of the different anomalies reported concurrently at the neuroanatomical, neurodevelopmental, biochemical, and genetic levels. It seems highly probable that the synaptic disorganization in the hippocampus concerns the regions crucial for encoding and contextual binding memory processes. The consequences of these deficits could result in schizophrenia patients experiencing major difficulties when facing usual events which have not been encoded with their proper context.

Theories of delusional disorders. An update and review

Delusional syndromes can occur in a number of psychiatric, neurological or other disorders. They can also be caused by neurotoxic agents (e.g., heavy metals) as well as substance addiction. There are several hypotheses on the underlying cognitive or emotional processes associated with organic factors of delusional disorders, depending on the patient groups examined and the methods used. The aim of this paper is to provide a comprehensive review and critical assessment of the various, rather heterogeneous theories in this field.

Selective impairment in the retrieval of family relationships in person identification: A case study of delusional misidentification

We describe a 74-year-old, right-handed woman who exhibited a peculiar form of delusional misidentification due to Alzheimer's disease (AD) combined with idiopathic normal pressure hydrocephalus (iNPH). The patient's most distinctive symptom was that she often misidentified her daughters as her sisters. She had severe atrophy of the bilateral medial temporal lobe and right-hemisphere-dominant hypoperfusion in the fronto-temporo-parietal cortices. Detailed tests revealed that she had a selective deficit in retrieving the family relationships between herself and her daughters/husband (i.e., she misidentified her daughters as her sisters and her husband as her father), despite being able to retrieve the names and faces of her family members, and some person-specific semantic information (e.g., occupation) related to them. We speculate that this specific type of misidentification can be elicited by failure to update semantic memory through the encoding of new episodic memory due to right-hemisphere-dominant fronto-temporal dysfunction.

The mystery of Morgellons disease: infection or delusion?

Morgellons disease is a mysterious skin disorder that was first described more than 300 years ago. The disease is characterized by fiber-like strands extruding from the skin in conjunction with various dermatologic and neuropsychiatric symptoms. In this respect, Morgellons disease resembles and may be confused with delusional parasitosis. The association with Lyme disease and the apparent response to antibacterial therapy suggest that Morgellons disease may be linked to an undefined infectious process. Further clinical and molecular research is needed to unlock the mystery of Morgellons disease.

Mechanisms of spontaneous confabulations: a strategic retrieval account

The 'temporality' hypothesis of confabulation posits that confabulations are true memories displaced in time, while the 'strategic retrieval' hypothesis suggests a general retrieval failure of which temporal confusion is a common symptom. Four confabulating patients with rupture of an anterior communicating artery (ACoA) aneurysm, eight non-confabulating ACoA controls and 16 normal controls participated in three experiments designed to test the two hypotheses. In Experiment 1, participants were tested on two continuous recognition tasks, one requiring temporal context distinctions, previously shown to be sensitive to confabulation and another that only requires content distinctions. Both manipulations were sensitive to confabulation, but not specific to it. Temporal context and content confusions (TCCs and CCs) can be explained as failures to make fine-grained distinctions within memory. In Experiment 2, free recall of semantic narratives that require strategic retrieval but are independent of temporal context was used to induce confabulations associated with remote memory, acquired before the onset of amnesia. Confabulators produced significantly more errors. Thus, when retrieval demands are equated, confabulations can be induced in the absence of temporal confusions. Only confabulators conflated semantic content from different remote semantic narratives and introduced idiosyncratic content, suggesting that qualitatively different mechanisms are responsible for distortions due to normal memory failure and for confabulation. Lesion analyses revealed that damage to ventromedial prefrontal cortex is sufficient for temporal context errors to occur, but additional orbitofrontal damage is crucial for spontaneous confabulation. In Experiment 3, we tested whether failure in memory monitoring is crucial for confabulation. Recognition of details from semantic and autobiographical narratives was used to minimize the initiation and search components of strategic retrieval. Only confabulators made more false alarms on both tasks, endorsed even highly implausible lures related to autobiographical events and were indiscriminately confident about their choices. These findings support a strategic retrieval account of confabulation of which monitoring is a critical component. Post-retrieval monitoring has at least two components: one is early, rapid and pre-conscious and the other is conscious and elaborate. Failure of at least the former is necessary and sufficient for confabulation. Other deficits, including TCC and CC, may be required for spontaneous confabulations to arise. The confluence of different sub-components of strategic retrieval would determine the content of confabulation and exacerbate its occurrence.

The entorhinal cortex in first-episode psychotic disorders: a structural magnetic resonance imaging study

OBJECTIVE

Neuropathological findings regarding the entorhinal cortex in schizophrenia are conflicting. The authors used structural magnetic resonance imaging to examine the entorhinal cortex volumes of healthy subjects and medication-naive patients experiencing their first episode of psychotic illness.

METHOD

The study included 33 patients with schizophrenia and related disorders, 11 patients with nonschizophrenic disorders, and 43 matched healthy subjects. All subjects were rated on the Scale for the Assessment of Positive Symptoms and the Scale for the Assessment of Negative Symptoms, and volumetric measurements of the entorhinal cortex were obtained for all subjects. The authors examined differences across the groups as well as clinical correlations of entorhinal cortex volumes adjusted for intracranial volume.

RESULTS

A significant diagnosis effect was seen in the left entorhinal cortex: patients with schizophrenia and related disorders and patients with nonschizophrenic psychotic disorders had smaller left entorhinal cortex volumes than healthy subjects. The mean entorhinal cortex volume of patients with schizophrenic disorders did not differ from that of patients with nonschizophrenic psychotic disorders. In patients with schizophrenic disorders, the entorhinal cortex volume positively correlated with severity of delusions. The mean entorhinal cortex volume of patients with nondelusional psychotic disorders was significantly smaller than that of patients with delusional psychotic disorders and healthy subjects.

CONCLUSIONS

Smaller entorhinal cortex volume in first-episode, neuroleptic-naive psychotic disorders may not be a confound of the effects of illness chronicity or antipsychotic treatment. Entorhinal cortex pathology appears to have a significant association with positive symptoms, specifically delusions. The impairment of functions in which the entorhinal cortex participates-such as novelty detection, associative learning, and processing episodic, recognition, and autobiographical memory-could be responsible for its association with psychotic disorders and delusions.

Parahippocampal gyrus in first episode psychotic disorders: a structural magnetic resonance imaging study

Neuropathological abnormalities in schizophrenia have been demonstrated in the parahippocampal gyrus (PHG). Only a few studies on first-episode neuroleptic-naive schizophrenia patients have been done using in vivo neuroimaging techniques. The authors examined the PHG morphology using structural MRI in neuroleptic-naive subjects with first episode psychoses. Volumetric measurements of PHG and intracranial volume (ICV) were obtained on subjects with schizophrenia and schizoaffective disorders (SCZ; n = 33), nonschizophrenia psychotic disorders (NSCZ; n = 11) and matched healthy subjects (HS; n = 43). The subjects were rated on the Brief Psychiatric Rating Scale (BPRS). Group differences and clinical correlations of ICV-adjusted PHG volumes were examined. Left PHG was significantly different across the groups consisting of SCZ, NSCZ and HS. PHG was larger in NSCZ compared to SCZ but not relative to HS. Bilaterally, PHG was no different between SCZ and HS. In pooled psychotic patients, the PHG volume negatively correlated with total positive symptom, delusion and conceptual disorganization scores on BPRS. Patients with delusions had relatively smaller PHG compared to nondelusional subjects. Observed differences in PHG volume in first-episode neuroleptic-naive patients suggest that these observations are not confounded by illness chronicity or medication effects. Significant association of PHG volume with psychotic symptoms suggests that PHG pathology plays an important role in the etiopathology of psychosis and its symptoms.

Spontaneous confabulation, reality monitoring, and the limbic system--a review

Patients with anterior limbic damage may present a distinct syndrome, spontaneous confabulation: they fail in common memory tests, act on the basis of previous habits rather than currently relevant memories, produce confabulations composed of elements of past true events, are disorientated, and are absolutely convinced about the veracity of their perceived reality. Spontaneous confabulation is independent of other false memories, such as, provoked confabulations or illusory recognition. Studies showed that spontaneous confabulators fail to suppress (inactivate) evoked memories that do not pertain to ongoing reality. Rehabilitation differs from other memory failures. Prognosis depends on the lesion site, but recovery is always associated with recovery of this suppression capacity. Lesions typically involve the posterior medial orbitofrontal cortex or its connections in the basal forebrain. Imaging and evoked potential studies in healthy subjects support the idea that the anterior limbic system provides a reality monitoring mechanism which selects memories of current relevance by suppressing (inactivating) currently irrelevant memories. This mechanism appears to adjust the cortical representation of activated memories before their content is recognised and consolidated. Comparison with animal studies suggests that human reality monitoring is a property of the brain's reward system.

Increased neocortical neurofibrillary tangle density in subjects with Alzheimer disease and psychosis

BACKGROUND

Psychosis is common in patients with Alzheimer disease. While the relationship between psychosis and clinical variables has been examined frequently, few studies have examined the relationship between psychosis and the 2 major neuropathological hallmarks of Alzheimer disease: neurofibrillary tangles and senile plaques. We characterized the occurrence of psychosis in relation to dementia severity and determined if subjects with Alzheimer disease and psychosis had a greater neurofibrillary tangle or senile plaque burden than subjects with Alzheimer disease and no psychosis.

METHODS

One hundred nine subjects with Alzheimer disease were followed longitudinally with semistructured assessments in order to assign a Clinical Dementia Rating and determine whether psychosis was present. After the subjects died, their brains were obtained for histological examination. Analysis of variance was used to compare the densities of neurofibrillary tangles, total senile plaques, and cored senile plaques in subjects with psychosis vs subjects without psychosis, in several neocortical regions, the hippocampus, and the entorhinal cortex.

RESULTS

Psychosis occurred commonly in Alzheimer disease, affecting 63% of subjects. The frequency of psychosis increased with increasing dementia severity. More importantly, we found that subjects with psychosis had a 2.3-fold (95% confidence interval, 1.2-3.9) greater density of neocortical neurofibrillary tangles than did subjects without psychosis. The increase was independent of dementia severity. No similar relationship with psychosis was seen for total senile plaques or cored senile plaques.

CONCLUSIONS

The increase in psychosis frequency that occurs with the progression of dementia severity and the independent association between psychosis and neurofibrillary tangle density suggest the possibility that some common underlying process or processes specific to Alzheimer disease may regulate both phenomena. Arch Gen Psychiatry. 2000;57:1165-1173.

Schizophrenia: an illness of distorted reality

Schizophrenia is a seriously disturbing disorder, both for the victim and for their families. Although treatments are available which can effectively control symptoms, their side effects are severe enough to cause many sufferers to discontinue taking them and their actions are not properly understood.

Hallucinations, REM sleep, and Parkinson's disease: a medical hypothesis

BACKGROUND

Patients with PD can have disabling visual hallucinations associated with dopaminergic therapy. Sleep disorders, including vivid dreams and REM sleep with motor behaviors (RBD), are frequent in these patients.

METHODS

The association of hallucinations and REM sleep both at night and during the day was examined in 10 consecutive nondemented patients with long-standing levodopa-responsive PD and hallucinations. Seven patients presented with paranoia and paranoid delusions. Overnight sleep recordings and standard multiple daytime sleep latency test were performed. The results were compared to those of 10 similar patients with PD not experiencing hallucinations.

RESULTS

RBD was detected in all 10 patients with hallucinations and in six without. Although nighttime sleep conditions were similar in both groups, hallucinators tended to be sleepier during the day. Delusions following nighttime REM period and daytime REM onsets were observed in three and eight of the hallucinators, and zero and two of the others. Daytime hallucinations, coincident with REM sleep intrusions during periods of wakefulness, were reported only by hallucinators. Postmortem examination of the brain of one patient showed numerous Lewy bodies in neurons of the subcoeruleus nucleus, a region that is involved in REM sleep control.

CONCLUSION

The visual hallucinations that coincide with daytime episodes of REM sleep in patients who also experience post-REM delusions at night may be dream imagery. Psychosis in patients with PD may therefore reflect a narcolepsy-like REM sleep disorder.

Bilateral anterior cortical atrophy and subcortical atrophy in reduplicative paramnesia: a case-control study of computed tomography in 10 patients

OBJECTIVE

Reduplicative paramnesia (RP) is thought to be related to other delusional misidentification syndromes (DMS) such as Capgras syndrome. DMS are thought to occur when brain lesions disrupt cortical functioning. This study tests this hypothesis and tries to understand whether focal lesions are as important in the etiology of RP as they are in other types of DMS.

METHOD

The computed tomography (CT) scans of 10 consecutive psychiatric inpatients with RP and another principal psychiatric diagnosis were compared with those of control patients without RP matched for age, sex, and principal psychiatric diagnosis. The scans were assessed blindly by a neuroradiologist using a previously published rating scale for the presence of lesions in 11 discrete anatomic areas. The differences between the 2 groups were examined statistically using log-linear analysis.

RESULTS

Statistical analysis revealed that index patient cortical atrophy, cortical fissure enlargement, and deep brain atrophy distinguished the 2 groups significantly (P < 0.05).

CONCLUSIONS

Bilateral anterior cortical, brain stem, and cerebellar vermis atrophy and dysfunction may be important in the pathogenesis of RP in particular and of DMS in general.

Candidate neuroanatomic substrates of psychosis in old-aged depression

1. The authors investigated the candidate neuroanatomic substrates underlying delusional thought disorder in old-aged depressed patients by using magnetic resonance imaging (MRI), and examined the relationship between volumes for individual brain structures and clinical correlates of particular relevance to depression: executive cognitive impairment and global severity of depression. 2. MR morphometry was performed on nineteen deluded depressed patients and 26 non-deluded depressed patients, all older than 55 years of age. Subjects were administered a neuropsychological test battery and measures of depression. 3. The absolute volume of prefrontal cortex (PFC) was smaller in the deluded depressed group than in non-deluded depressed group (131.79 +/- 37.26 ml vs. 152.65 +/- 26.13 ml, p = 0.03); a difference that was statistically significant even after adjusting for the effect of whole brain volume (p = 0.01). No group differences were observed in the volumes of the basal ganglia, the temporal lobes, the superior temporal gyri, the amygdala-hippocampal complex, the lateral ventricles, or whole brain. The relative volume of PFC correlated inversely and significantly with the index of Wisconsin Card Sorting Test (WCST) performance (r = -0.76, p < 0.01) in depressed patients. 4. PFC may be one of the candidate neuroanatomic substrates underlying delusional thought disorder in old-aged depression.

The temporolimbic system theory of positive schizophrenic symptoms

This article proposes that subtle structural and functional disturbance of limbic key structures in the medial temporal lobe-especially of the left hippocampal formation and parahippocampal gyrus-can explain the so-called positive symptoms of schizophrenia. After presenting pathophysiological considerations linking limbic dysfunction to schizophrenia, the article reviews evidence from structural, biochemical, and functional studies supporting the theory. Also discussed here are neurodevelopmental and laterality aspects, as well as predictions, questions, and future tasks derived from the theory.

The temporolimbic system theory of paranoid schizophrenia

The hippocampus serves as a funnel for heavily processed sensory information that has converged at the entorhinal cortex. Lesions of the hippocampus do not alter incoming sensory or motor information but, rather, alter their integration with our baggage of emotional experiences and social values. According to Bogerts, such a lesion would be ideally situated to result in laboriously processed sensory information that is out of context to our outside environment. In this regard, Bogerts describes the pathological findings of a patient with a gross delusional disorder. The salient finding at autopsy was a developmental lesion in the left posterior parahippocampal gyrus. Although a number of lesions have been described in the brains of patients with schizophrenia, Bogerts believes that those in the limbic system appear critical to the expression of paranoid symptoms.

Violent behaviors associated with the antichrist delusion

Delusions involving the antichrist concept have been occasionally reported. Some cases of the antichrist delusion have been associated with violent behavior. In this article we describe the case of a man who suffered from a chronic antichrist delusion and who also displayed repeated and serious violent behaviors. We also discuss the role of the antichrist delusion as well as other psychotic symptoms in the genesis of violence in the present case.

Misidentifications

Misidentifications are misperceptions (i.e., a form of illusion) with an associated belief or elaboration that is held with delusional intensity. Although misidentifications have been defined in several ways, four main types have been described: (a) presence of persons in the patient's own house (the phantom boarder syndrome); (b) misidentification of the patient's own self (often seen as a misrecognition of his or her own mirror reflection); (c) misidentification of other persons; and (d) misidentification of events on television (the patient imagines these events are occurring in real three-dimensional space).

Neuropathology of psychotic symptoms in Alzheimer's disease

An impressive body of literature has been published on the relationship between psychotic symptoms in Alzheimer's disease and pathology demonstrated primarily by neuroimaging and biochemistry studies. Jacoby and Levy in 1980 and Burns and colleagues in 1990, for example, reported less severe atrophy in delusional patients with Alzheimer's disease than in nondelusional patients with Alzheimer's disease. The author and colleagues have found that smaller ventricle-brain ratios are associated with delusions of theft in Alzheimer's disease. Zubenko (1991) and Doty (1989) have reported that delusions and hallucinations in patients with Alzheimer's disease are associated with decreased amounts of serotonin.

Delusional misidentification and subsequent dementia: a clinical and neuropathological study

An 81-year-old man presented with psychotic episodes involving the delusion that his wife had been replaced by a closely resembling double (the so-called Capgras delusion). A comprehensive neuropsychological investigation revealed no signs of dementia at that time, but in the subsequent course the patient became demented and died 5 years later. Neuropathological and neurochemical examination displayed many diffuse plaques in the cortex that escaped detection by Congo-red but were clearly demonstrated by antibodies raised to beta-amyloid protein. Neurofibrillary tangles were absent in the cortex. Antiubiquitin immunohistochemistry revealed some cortical and subcortical Lewy bodies. The hippocampus and the majority of the nigral cells were intact. However, in the frontal and parietal white-matter many small lacunar infarcts were found due to arteriosclerotic and hypertensive vessel wall changes. Though the etiology of psychotic symptoms in the context of dementia is complex, this study shows the possible significance of white-matter lesions in the pathogenesis of delusions and subsequent dementia.

Delusional disorders are a naturally occurring 'experimental psychosis'

A delusion can only be 'explained' if it can be correlated with a demonstrable brain event, and this is only beginning to be possible. The misidentification syndromes are leading the way in demonstrating a close relationship between quite specific brain abnormalities and highly characteristic delusional symptoms. Although delusional disorder (DSM-IV 297.10) and its treatment are well described, virtually no investigations have been carried out on the neuropathological substrate. This article suggests that delusional disorder is a naturally occurring 'model psychosis' which would reward experimental study.

Frontal lobe tumor associated with late-onset seizure and psychosis: a case report

This is a report of a 55-year-old woman with a 6-year history of uncontrollable complex partial seizure and severe delusion. A computed tomography (CT) brain scan showed a nonenhanced low density area with an ill-defined mass located at the right frontal lobe. Magnetic resonance imaging (MRI) demonstrated an area of hyperintensity on T2-weighted images. After a tumorectomy, the patient gradually recovered from the seizures and delusion. A histological diagnosis showed a mixed oligoastrocytoma or dysembryoplastic neuroepithelial tumor (DNT). The clinical and pathological features of the tumor as well as its relation to psychosis were discussed.

A "mock up" of schizophrenia: temporal lobe epilepsy and schizophrenia-like psychosis

Schizophrenia-like psychoses occur more frequently than expected in patients with chronic temporal lobe epilepsy. We have analyzed pathological and clinical data from a series (n = 249) of temporal lobectomies to determine the factors that may relate to the development of schizophrenia-like psychosis. Schizophrenia-like psychoses did not occur at random; they were significantly associated with lesions that (1) originated in the fetus or perinatally, (2) affected neurons in the medial temporal lobe, and (3) gave an early age of first fit. Gangliogliomas--developmental lesions of the medial temporal lobe containing aberrant neurons--were disproportionately (p less than 0.001) associated with risk of psychosis. Schizophrenia-like psychoses arising preoperatively occurred more often (p = 0.1) with left-sided lesions. Asymmetry of lesion was not present in cases with postoperative psychoses. These findings are of interest in relation to recent studies suggesting that the structural abnormalities found in the brains of schizophrenics arise during fetal brain development.

The ventricular-brain ratio (VBR) in functional psychoses: the relationship of lateral ventricular and total intracranial area

CT scans were performed on 72 consecutive patients with a functional psychosis, and compared with 50 community controls. There was a specific difference in lateral ventricular area between these two groups but it accounted for only 11% of the variance in this measure. In contrast, racial and sexual differences in the ventricular-brain ratio (VBR) related to differences in intracranial area. It is argued that analysis of variance, using lateral ventricular area and intra-cranial area, is more informative than VBR in examining these structural changes in functional psychoses.

Reduplicative paramnesia: possible anatomical and neuropsychological mechanisms

A patient is reported who presented with reduplicative paramnesia following a vascular lesion in the right frontal region. Neuropsychological examination revealed significant memory impairment, perservation on a problem solving task and marked left-sided inattention. Recovery from the paramnesic episode was accompanied by selective resolution of the original cognitive deficits. It is suggested that focal right frontal pathology may represent a sufficient condition for the occurrence of reduplicative paramnesia, and that the underlying mechanisms may be dependent on a particular combination and severity of memory, visuospatial and conceptual deficits.

Increased CSF amino acids and ventricular enlargement in schizophrenia: a preliminary study

We found significantly higher levels of cerebrospinal fluid alanine, glycine, leucine, and phenylalanine in schizophrenic patients compared to healthy controls. Ventricular enlargement was present in 4 of 11 schizophrenics, and elevated CSF alanine was highly correlated with ventricular enlargement. The implications of these findings are discussed.