Absence of the adhesio interthalamica as a marker of early developmental neuropathology in schizophrenia: an MRI and postmortem histologic study

Several recent studies have reported an association between midline cerebral malformations (e.g., corpus callosum, cavum septum pellucidum) and schizophrenia. The authors investigated whether absence of the adhesio interthalamica (AI), a midline structure that develops in concert with prominent features of the ventricular system soon after the bridge from the late embryonic stages to early fetal life, might constitute a marker of early developmental neuropathologic changes in schizophrenia. Eighty-two patients (54 men, 28 women) with a diagnosis of first-episode schizophrenia (FES) were recruited from consecutive admissions to a psychiatric inpatient service. Fifty-two healthy control subjects (30 men, 22 women) were recruited and matched to the patient sample on distributions of sex and age. Magnetic resonance imaging studies were performed, and the presence versus absence of the AI was determined for each subject. The length and volume of the third ventricle were measured for each subject. The AI was found to be absent more often among patients with FES compared with control subjects, and patients without an observable AI also had larger third-ventricle volumes. These differences in presence or absence of the AI observed in vivo (but not in a comparable postmortem sample of histologically fixed and prepared brain slices), which are likely related to third-ventricle enlargement, may represent yet another early developmental marker of cerebral malformation among patients with FES.

Meta-analysis of symptom factors in schizophrenia

Factor and correlational analyses have been used to characterize symptom dimensions in schizophrenia, though they have yielded divergent models. This study used meta-analysis of published work to determine the number and composition of symptom dimensions. Principal components analysis of data from 10 empirical studies (pooled n = 896) yielded three factors, 'positive', 'negative' and 'conceptual disorganization'. The findings suggest that a three-factor solution is a relatively stable outcome of studies assessing these symptoms in chronic patients, and that some symptoms (alogia, attentional impairment) are less likely to load uniquely on a single factor.

Brain morphometric comparison of first-episode schizophrenia and temporal lobe epilepsy

BACKGROUND

Converging evidence has suggested that the abnormalities in brain morphology observed in schizophrenia are similar to those seen in temporal lobe epilepsy (TLE). The purpose of this study was to compare the features of these groups directly with measures of the brain using magnetic resonance (MR) morphometry.

METHOD

Morphometric measures of ventricular and hippocampal volumes obtained from FLASH MR images were studied in 32 patients with first-episode schizophrenia (FES), 39 patients with TLE (21 left, 18 right), and 42 healthy controls.

RESULTS

Ventricular volumes in the FES and TLE groups were both significantly larger that those seen in controls and did not differ from each other. The FES group showed significantly larger temporal horns, while the TLE group had relatively larger frontal horns. Analyses of hippocampal volumes revealed a significant group by hemisphere effect. The FES group showed relative reductions in left hippocampal volume that were comparable only to TLE patients with seizures originating from the left hemisphere.

CONCLUSION

The results indicate that FES and TLE groups both show evidence of ventricular enlargement. Lateralised morphological abnormalities of the hippocampal formation in FES and left TLE are comparable, and may be specific to temporolimbic regions.

Neurocognitive impairment in schizophrenia and how it affects treatment options

OBJECTIVE

To review the roles played by neurocognitive assessment in the treatment of schizophrenia and in the design of treatment research strategies.

METHOD

A review of the literature and summaries of clinical and research implications are presented, with directions for future research.

RESULTS

Neurocognitive deficits are now targets of antipsychotic drug treatment and should increasingly be used to refine both theory and clinical practice by considering the effects of treatments at the level of neural systems.

CONCLUSION

Efforts to bridge the gaps between preclinical and clinical assessments should yield large rewards in drug development and individualized treatment strategies. Functional neuroimaging may play a major role in these developments.

Anterior hippocampal volume reductions predict frontal lobe dysfunction in first episode schizophrenia

This study examined relations of mesiotemporal lobe tissue volumes with neuropsychological (NP) functions in a sample of patients with first episode schizophrenia. Three contiguous compartments of the mesiotemporal lobe were measured on magnetic resonance images, comprising primarily amygdaloid, anterior hippocampal, and posterior hippocampal tissue volumes. NP measures were derived from a comprehensive battery. Decreased volume selectively in the anterior hippocampal formation was associated with lower scores on measures of executive and motor functions usually considered sensitive to the integrity of frontal lobe systems. Measures of other NP functions, and global intellectual ability, were not related to mesiotemporal volumes. The findings that morphologic abnormalities in the mesiotemporal lobe are associated with impairment of frontal lobe functions point to a defect in an integrated functional system that includes both frontal and mesiotemporal components. The findings are consistent with the hypothesis that neurodevelopmental defects affecting the morphology of the anterior hippocampal formation may be manifest later in life as impairments in fronto-limbic control. </p>.

Cerebellar volume asymmetries are related to handedness: a quantitative MRI study

Four cerebellar subregions were delineated (left, right; anterior, posterior), and their volumes measured on contiguous 3.1 mm coronal MR images in 15 dextral and 8 nondextral healthy control subjects. (1) Left and right cerebellar hemisphere volume asymmetries interacted with anterior-posterior level (anterior: right > left; posterior: left > right), following a pattern commonly found in the neocortex; (2) A significant handedness effect was found (P < or =0.01) on a composite index of cerebellar asymmetry, such that dextrals showed more asymmetry than nondextrals. These data suggest that the same pattern of asymmetries observed at the neocortical level is also present in the metencephalon. These asymmetries, possibly resulting from multiple developmental growth gradients acting on the metencephalon early in gestation, are associated with handedness differences in adulthood.

Absence of regional hemispheric volume asymmetries in first-episode schizophrenia

OBJECTIVE

The goal of this study was to determine whether patients experiencing their first episode of schizophrenia differ from healthy subjects in regional cerebral hemispheric volumes or asymmetries.

METHOD

Regional volumes corresponding to prefrontal, premotor, sensorimotor, occipitoparietal, and temporal lobes in each hemisphere were measured on contiguous coronal magnetic resonance images in 70 patients experiencing their first episode of schizophrenia and in 51 healthy comparison subjects.

RESULTS

Patients did not differ from the comparison subjects in regional or total hemispheric volumes, but they had abnormal hemispheric asymmetries. Subjects in the comparison group had significant lateral asymmetries in each region: their occipitoparietal and sensorimotor regions were larger on the left, and their premotor, prefrontal, and temporal regions were larger on the right. Patients lacked lateral asymmetries and showed significantly less asymmetry than healthy subjects in occipitoparietal, premotor, and prefrontal regions. Absence of the normal asymmetry was more common among patients initially diagnosed with the undifferentiated than with the paranoid subtype of schizophrenia and was associated with more severe negative symptoms among men. Asymmetries were related to sex and handedness regardless of diagnosis; specifically, dextral men showed more asymmetry than nondextral men or dextral women.

CONCLUSIONS

The absence of normal hemispheric asymmetries suggests an anomaly in the development of laterally specialized cerebral systems in schizophrenia, and this may be associated with an initial presentation of nonparanoid psychosis.

Increase in caudate nuclei volumes of first-episode schizophrenic patients taking antipsychotic drugs

OBJECTIVE

This study examined the pathomorphology of the caudate nuclei in first-episode schizophrenic patients with minimal previous neuroleptic exposure.

METHOD

Magnetic resonance imaging (MRI) of the brain was used to examine longitudinally the caudate pathomorphology in 29 first-episode schizophrenic patients and 10 healthy comparison subjects. MRI scans were obtained after the subjects entered the study and at 18-month follow-up. The patients were treated with standardized neuroleptic regimens during the 18-month period. Volumetric assessments of the cerebral cortex, lateral ventricles, and caudate nuclei were performed on T1-weighted coronal brain sections. In addition, the patients were systematically evaluated for psychopathology at baseline and during treatment.

RESULTS

Caudate volumes increased 5.7% in the patients during the 18-month treatment interval, whereas they decreased 1.6% in the comparison subjects over the same time period. Greater amounts of antipsychotic medication received by patients before the first scan and younger age at the time of the first scan were associated with larger increases in caudate volume.

CONCLUSIONS

Caudate enlargement occurs early in the course of treatment in young first-episode schizophrenic patients. This may be a result of an interaction between neuroleptic treatment and the plasticity of dopaminergic neuronal systems in young patients.

Cerebral morphometry and clozapine treatment in schizophrenia

Studies of brain morphology in schizophrenia may be informative about basic pathophysiologic processes, provide clinically useful indicators of treatment response, and lead to the identification of markers for selective treatment effects. This paper reviews findings from magnetic resonance imaging studies of patients with schizophrenia conducted at Hillside Hospital, with special attention to (1) findings that have helped distinguish patients who respond well to typical neuroleptics from those who have gone on to trials of clozapine, (2) the capacity of morphological measures to predict clozapine treatment response, and (3) the possibility that selective hypertrophy of striatal structure may be caused by chronic treatment with typical neuroleptics, but not by clozapine.

Hippocampus-amygdala volumes and psychopathology in chronic schizophrenia

Volumes of the mesiotemporal structures (hippocampus-amygdala complex) were measured in 19 men who were chronic multiepisode schizophrenics and 18 age-matched healthy controls using T1-weighted contiguous coronal magnetic resonance images of 3.1-mm width. Using the level of the mammillary bodies as an anatomical landmark, the whole hippocampus-amygdala complex was divided into an anterior section (mainly containing amygdaloid tissue) and a posterior section (mainly containing the hippocampal formation). Total mesiotemporal tissue volume was reduced significantly in the patient group compared to controls (-11%), with significant reductions in both left (-20%) and right (-15%) hippocampal sections. Reduced limbic tissue volume was associated with increased severity of psychopathology. Severity of positive psychotic symptoms (Brief Psychiatric Rating Scale [BPRS] psychosis factor) was correlated significantly with right and left total mesiotemporal volumes (Spearman rho's = -0.61 p < 0.01). Negative symptom scores (BPRS anergia factor, Scale for Assessment of Negative Symptoms [SANS] global items) were not significantly correlated with any mesiotemporal tissue volumes. The data corroborate and extend previous findings of temporolimbic structure volume reduction in schizophrenia, and suggest that the positive psychotic symptoms of schizophrenia are associated with anatomic anomalies in mesiotemporal structure.

Volumes of ventricular system subdivisions measured from magnetic resonance images in first-episode schizophrenic patients

In vivo brain imaging and postmortem investigations have demonstrated structural anomalies in the brains of schizophrenic patients. However, previous studies have not established clear relationships between the characteristic symptoms of the disorder and neuropathologic changes in specific brain regions. We have obtained high-resolution magnetic resonance brain images of first-episode schizophrenic and normal control subjects and, with a computerized mensuration system, determined the volumes of the different components of the entire ventricular system. Volumes of ventricular segments were significantly larger in patients than controls (differences ranged from 17% to 40%). Temporal horn enlargement consistently demonstrated significant correlations with a broad range of schizophrenic symptoms. Our data indicate that anomalies of limbic structures in the medial temporal lobe surrounding the temporal horn play a crucial pathophysiologic role in schizophrenia.

Intellectual deficits in first-episode schizophrenia: evidence for progressive deterioration

The developmental processes leading to neuropsychological deficits in schizophrenia are poorly understood. Both early developmental defects and subsequent deterioration may occur. Intelligence test profiles are often used to estimate premorbid ability and deterioration from prior levels of functioning. These characteristics were assessed in samples of first-episode (n = 51) and chronic (n = 50) schizophrenic patients. Although the groups showed few differences on tests to estimate premorbid intellectual ability, the chronic group performed worse on measures considered sensitive to deterioration. Dextral (right-handed) patients tended to have better performance; this effect was marked in the first-episode sample, especially on verbal tests. Male patients showed more evidence of deterioration than female patients. Subgroups differing in the time course of premorbid social dysfunction also differed in intelligence test profiles, suggesting that estimates of social and cognitive deterioration may have concurrent validity. The results support the hypothesis that patients differ in the course of cognitive decline and suggest that deterioration of function may follow the onset of overt psychosis in some patients. Prospective longitudinal studies of first-episode schizophrenic patients could directly test this hypothesis.

Prospective study of psychobiology in first-episode schizophrenia at Hillside Hospital

Heterogeneity has been a consistent problem in the research and treatment of schizophrenia. Despite marked variation in the onset, phenomenology, treatment response and outcome of schizophrenic patients, our ability to identify subtypes is remarkably limited. A major problem in schizophrenia research has been the use of cross-sectional study designs and heterogeneous patient samples at different stages of the illness and who have been previously exposed to neuroleptics which have potentially confounding effects on the disease. This study intends to identify biologic correlates of the phenomenology and course of schizophrenia by using a prospective, longitudinal, repeated measures design assessing biologic and clinical parameters including measures of psychopathology, side effects, and social adjustment to examine clinical variables of treatment response, illness course, and outcome; measures of central nervous system dopamine activity and brain morphology in patients, from the onset of their illness. Patients were ascertained at hospital admission and assessed with a battery of clinical, neuropsychologic, and biologic measures before undergoing standardized treatment for the acute and maintenance phases of the illness. Upon completion, approximately 120 first-episode patients will have entered the study and will have been followed prospectively for up to 5 years and assessed at specific time intervals. Preliminary results reveal significant abnormalities in brain morphology, growth hormone secretion, eye movement function, and psychotogenic response to dopamine agonists in first-episode, treatment-naive patients which are associated with treatment response and outcome. This article describes the study's rationale, design, and methods, and a summary of the published results to date. These are discussed in terms of their significance for putative clinical subtypes and pathophysiological models of schizophrenia.

Reduced temporal limbic structure volumes on magnetic resonance images in first episode schizophrenia

Pathomorphology of the limbic system has been described in post-mortem studies of schizophrenia. To determine whether this could be detected in living patients and was not secondary to the treatment or the chronicity of the disease itself, we measured the volumes of the hippocampus-amygdala complex and adjoining temporal horns of 34 patients in their first episode of schizophrenia and 25 normal volunteers using T1 weighted contiguous coronal magnetic resonance images of 3.1 mm width. The results demonstrate abnormal medial temporal lobe morphology in a subgroup of patients at the onset of their illness. There were clear laterality effects and sex differences: hippocampal tissue was significantly smaller only in the left hemisphere of male patients, whereas enlargement of the whole temporal horn or its anterior portion was present on the left side in both sexes. Dysfunction of the limbic mesiotemporal structures might explain some of the clinical features of the disease.

A reticulo-frontal disconnection syndrome

Persistent executive deficit, usually seen following prefrontal damage, is reported in a patient recovering from head trauma. Repeated neuroradidological examinations failed to reveal a lesion within the frontal lobes, but a circumscribed lesion in the ventral mesencephalic tegmentum was found. It is proposed that the observed syndrome was caused by damage to mesencephalic reticular nuclei and their projections into prefrontal cortex. The concept of a "reticulo-frontal disconnection syndrome" is introduced and its possible role in head trauma and schizophrenia discussed.

Schizophrenic symptoms and deterioration. Relation to computed tomographic findings

Thirty-two patients with a research diagnosis of chronic schizophrenia were studied using structured clinical scales for premorbid adjustment, clinical symptomatology, and social deterioration. By computed axial tomography (CAT), ventricle-brain ratio (VBR) and cortical atrophy were assessed. The relation between the clinical variables and CAT findings was assessed using linear correlation. CAT-based subgroups were compared using univariate analysis of variance. Previous findings of ventricular enlargement and cortical atrophy in some schizophrenics were replicated. Premorbid asociality and social deterioration were found to have a modest, positive relation with CAT findings but formal thought disorder had a negative relation to ventricle size. There was no relation between the negative symptoms and CAT measures. Within the CAT-positive group the presence of cortical atrophy appeared to be associated with a more severe illness compared with those with ventricular enlargement but the sample sizes were too small to obtain any significant differences.

Neuropsychological deterioration and CT scan findings in chronic schizophrenia

Structural abnormalities of the brain, particularly ventricular enlargement and prominence of cortical sulci, have been documented reliably in CT scan investigations of chronic schizophrenic patients. Although the clinical significance of these findings is still obscure, neuropsychological (NP) deficits have emerged as relatively robust correlates of the structural anomalies. Unfortunately, it remains unknown whether the previous findings of NP impairment in association with CT scan abnormalities reflect poor premorbid abilities or deterioration from previously higher levels. This study involved administration of an extensive NP battery and CT scans in a chronic schizophrenic sample. In addition to global and specific scales of NP functions, indices of premorbid ability and deterioration were also employed. The results are consistent with the hypothesis that CT scan findings are associated more with deterioration of functioning than with global measures of NP dysfunction or poor premorbid ability. Conversely, the findings suggest that in patients with normal scans, NP morbidity may be a consequence of failure in the acquisition of a normal cognitive repertoire.

Motor perseverations in schizophrenia

Classical neuropsychological descriptions of prefrontal syndromes emphasize qualitative, productive symptoms, among which the phenomena known as motor perseverations occupy a central position. The now popular assertions that selective prefrontal dysfunction characterizes chronic schizophrenia would be more compelling if such productive symptoms could be reliably elicited in these patients. The present study demonstrated the presence of conspicuous motor perseverations in a sample of chronic schizophrenic inpatients, elicited using techniques that were developed and validated in studies of patients with known frontal lobe lesions. The observedperseverations closely resemble, both in severity and typology, those documented in cases with focal damage to prefrontal cortex. The findings support the contention that prefrontal dysfunction exists in chronic schizophrenia.