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.