A profile of cortical gray matter volume deficits characteristic of schizophrenia

P300 amplitude is related to clinical state in severely and moderately ill patients with schizophrenia

BACKGROUND

Relationships between illness severity and neurobiologic abnormalities in schizophrenia were studied in subpopulations varying in clinical severity.

METHODS

Auditory ERPs were collected from 28 severely ill, chronically hospitalized schizophrenic men from a state hospital; 29 moderately ill inpatient and outpatient schizophrenic men from a veterans hospital; and 30 healthy male subjects from the community as controls. Clinical symptoms were evaluated in patients using the Brief Psychiatric Rating Scale (BPRS).

RESULTS

Both schizophrenic patient groups had smaller P300 amplitude than the control subjects. Severely ill patients had smaller P300s than moderately ill patients and scored higher on three BPRS factor scores as well as BPRS Total. Among severely ill patients, P300 amplitude was unrelated to clinical symptoms. Among moderately ill patients, P300 was related to Withdrawal/Retardation, Anxiety/Depression, and BPRS Total. After combining patients, Thinking Disturbance emerged as an additional correlate of P300. Group differences in P300 could not be accounted for by group differences in symptom severity using analysis of covariance.

CONCLUSIONS

Reduced P300 amplitude marks the diagnosis of schizophrenia, but also reflects individual differences in severity, including positive symptoms. Previous failures to find relationships between positive symptoms and P300 may have been due to a restricted range of clinical severity.

Mapping of grey matter changes in schizophrenia

Studies of brain changes in schizophrenia have suggested that the disorder is associated with reductions in both global and regional grey matter. In this study, we used structural neuroimaging to differentiate between these two types of change and to examine regional grey matter throughout the whole brain. Grey matter from magnetic resonance images was segmented and transformed into stereotactic space, and patients with schizophrenia and controls were compared with respect to regional grey matter (after compensating for global grey matter differences). In two preliminary analyses to test our methodology, we demonstrated that: (1) in the transformed grey matter maps, voxel values at the location of the caudate nuclei were correlated with region-of-interest measurements of caudate area in native image space, and (2) the technique detected regional grey matter changes resulting from artificial lesions created in the native images. We then used a factorial design to examine data from two studies, comprising a total of 42 schizophrenics and 52 controls. Analysis of the main effect of schizophrenia on regional grey matter revealed significant reductions in (a) the right temporal pole, insula and amygdala, (b) the left temporal pole, insula and dorsolateral prefrontal cortex.

Severity of schizophrenia and magnetic resonance imaging abnormalities: a comparison of state and veterans hospital patients

BACKGROUND

The relationship between illness severity and neuroanatomical abnormalities in schizophrenia remains unclear. The purpose of this study was to test whether the pattern and extent of brain volume abnormalities differed between two patient groups, distinguished by their overall severity and clinical course of schizophrenia.

METHODS

Subjects were 56 severely ill, chronically hospitalized schizophrenic men from Napa State Hospital (SH-SZ), 44 moderately ill, acutely hospitalized schizophrenic men from the Palo Alto Veterans Administration Health Care System (VA-SZ), and 52 healthy male control subjects. Temporolimbic, ventricular, and frontoparietal volumes, quantified from 3-mm coronal spin-echo magnetic resonance images and adjusted for cerebral volume and age, were compared using analysis of variance.

RESULTS

Compared to control subjects, both SZ groups had smaller (p < .05) temporal lobe and frontoparietal gray matter volumes and larger ventricles and temporal sulci. Whereas SH-SZ had more pronounced cerebrospinal fluid and frontoparietal abnormalities relative to VA-SZ; VA-SZ had greater temporal lobe gray matter deficits. Neither patients group had hippocampal or cerebral volume deficits relative to control subjects. There were no differences between diagnostic subtypes.

CONCLUSIONS

The magnitude of volume abnormalities in schizophrenia varies with respect to disease severity and to brain region, but disease severity is not associated with anatomically distinct subgroups.

Association between regional brain volumes and clozapine response in schizophrenia

BACKGROUND

Clozapine has shown considerable therapeutic promise in the treatment of schizophrenia; however, the clinical risks and initial high treatment costs associated with its administration motivate the search to identify patients who will best respond. Neuroimaging studies have suggested that prefrontal sulcal prominence may be a predictor of nonresponsiveness.

METHODS

We used magnetic resonance imaging (MRI) to test whether volumes in any cortical regions of the brain were associated with symptom improvement with clozapine treatment. The 21 schizophrenic men studied were clinically evaluated during treatment with typical neuroleptics (baseline) and after a mean of 6.2 months treatment with clozapine (final dose 300-900, median = 562 mg/day). At least a 20% improvement on total Brief Psychiatric Rating Scale (BPRS) was seen in 47.6% of the schizophrenics. Clinical improvement was regressed on baseline differences in clinical severity, and the residual scores were related to MRI values.

RESULTS

Patients with larger anterior superior temporal lobe cerebrospinal fluid volumes (primarily sylvian fissure) showed greater improvement on total BPRS and withdrawal/retardation symptoms.

CONCLUSIONS

Even schizophrenics with significant brain dysmorphology can have a positive clinical response to clozapine.