Pharmacotherapy of first-episode schizophrenia

BACKGROUND

A growing interest in first-episode schizophrenia reflects the belief that this line of investigation will lead to further developments regarding schizophrenia's aetiology, course and outcome.

METHOD

Evidence from more recent clinical trials involving first-episode schizophrenia is integrated with neuroimaging data, specifically positron emission tomography, to provide direction regarding pharmacotherapy.

RESULTS

Individuals with a first episode of schizophrenia appear particularly responsive to pharmacotherapy, as well as quite sensitive to side-effects. At the same time, current clinical and receptor-binding data support the efficacy of low-dose neuroleptic treatment.

CONCLUSIONS

Early and effective treatment of schizophrenia has been associated with better long-term outcome. Low-dose neuroleptic therapy is an effective treatment strategy and the diminished risk of side-effects with this approach may further enhance compliance and outcome.

Temporal horn enlargement is present in schizophrenia and bipolar disorder

BACKGROUND

Ventricular enlargement and temporal lobe volume deficits have been demonstrated in patients with affective disorder as well as those with schizophrenia. This study compares quantitative measures of temporal lobe, hemispheric, and ventricular volumes in a group of patients with chronic schizophrenia and bipolar disorder and seeks to determine if the groups can be differentiated on the basis of measured brain abnormalities.

METHODS

A series of coronal magnetic resonance imaging sections were acquired and analyzed for each of 22 patients with chronic schizophrenia, 14 patients with bipolar disorder, and 15 community volunteers. Eleven regions of interest for each brain were defined, which included temporal lobe, superior temporal gyrus, hemisphere, lateral ventricle, third ventricle, and temporal horn measures. Tissue measures were obtained by tracing, and cerebrospinal fluid measures were obtained by fluid-tissue thresholding using specialized computer software.

RESULTS

Both patient groups had significantly larger temporal horn volumes in comparison with the control group both before and after correction for intracranial volume. The two patient groups did not differ from each other or controls on any other tissue or fluid measure.

CONCLUSIONS

This study confirms the findings of increased temporal horn volume in patients with schizophrenia and suggests that this structural abnormality does not differentiate the structural neuropathology of schizophrenia from that of bipolar disorder.

5-HT2 and D2 receptor occupancy of olanzapine in schizophrenia: a PET investigation

OBJECTIVE

Olanzapine is a new atypical antipsychotic recently introduced for the treatment of schizophrenia. The purpose of this study was to investigate olanzapine's binding to the serotonin 5-HT2 and dopamine D2 receptors in schizophrenic patients being treated with clinically relevant doses.

METHOD

Twelve patients with schizophrenia were randomly assigned to 5, 10, 15, or 20 mg/day of olanzapine in a prospective fashion. Three other subjects taking 30-40 mg/day were also included. Once steady-state plasma levels were achieved, dopamine D2 and serotonin 5-HT2 receptors were assessed by using [11C]raclopride and [18F]setoperone positron emission tomography imaging, respectively. Ratings of clinical status, extrapyramidal side effects, and prolactin levels were also obtained.

RESULTS

Olanzapine induced near saturation of the 5-HT2 receptors, even at 5 mg/day. Its D2 occupancy increased with dose: patients taking 5-20 mg/day showed 43%-80% D2 occupancy, while patients taking 30-40 mg/day showed 83%-88%.

CONCLUSIONS

Olanzapine is a potent 5-HT2 blocker and shows a higher 5-HT2 than D2 occupancy at all doses. However, its D2 occupancy is higher than that of clozapine and similar to that of risperidone. In the usual clinical dose range of 10-20 mg/day, its occupancy varies from 71% to 80%, and this restricted range may explain its freedom from extrapyramidal side effects and prolactin elevation. However, doses of 30 mg/day and higher are associated with more than 80% D2 occupancy and may have a higher likelihood of prolactin elevation and extrapyramidal side effects.

Functional network differences in schizophrenia: a rCBF study of semantic processing

Studies of regional cerebral blood flow in patients with schizophrenia have led to the idea that dysfunctional neurocircuitry may play a role in patients' cognitive deficits. The present PET study was designed to explore this idea by comparing the functional neural networks associated with semantic processing for patients and normal controls through structural equation modeling (path analysis). The patients showed significantly different neural interactions among frontal regions, between the frontal and temporal cortices, and between the frontal lobe and anterior cingulate than controls. These discrepancies were especially striking given there were minimal group differences in task performance. Results suggest that schizophrenia involves a neural abnormality that is evident in functional networks during cognitive performance.

Cerebral gray matter volume deficits in first episode psychosis

BACKGROUND

Structural brain differences including decreased gray matter and increased cerebrospinal fluid volumes have been observed in the brains of chronically ill patients with schizophrenia. We hypothesized that deficits in gray matter volume would be present in patients presenting with a first episode of nonaffective psychosis.

METHODS

We used magnetic resonance imaging to compare the brains of 77 patients assessed as having a first episode of psychosis (meeting DSM-III-R criteria for schizophrenia, schizophreniform disorder, schizoaffective disorder, delusional disorder, or psychotic disorder not otherwise specified) with those of 61 healthy controls matched for age, sex, race, and parental socioeconomic status. Axial, dual-echo scans of the whole brain were segmented into gray matter, white matter, and cerebrospinal fluid compartments using a computerized volumetric approach. These measures were corrected for the significant effects of intracranial volume and age prior to performing between-group comparisons.

RESULTS

The first episode psychosis group had significantly smaller gray matter volume (t[136] = -2.2; P = .03) and greater cerebrospinal fluid volume (t[136] = 2.5; P = .02) than normal controls. In the patient group, gray matter volumes were positively correlated with estimates of IQ but not with age of onset, duration of illness, or measures of premorbid functioning.

CONCLUSIONS

Deficits in gray matter volume are present in patients experiencing first episode nonaffective psychosis. The magnitude of these differences is smaller than has been described in more chronically ill patients.

MRI correlates of treatment response in first episode psychosis

It is not known whether the magnitude of the structural brain abnormalities that underlie schizophrenia is a determinant of the extent to which patients respond to antipsychotic medication. This study was undertaken in order to explore this relationship. Twenty-six patients receiving treatment for a first episode of psychosis were involved in both a study measuring treatment response and a magnetic resonance imaging (MRI) study. In the treatment study, haloperidol dose was increased weekly beginning at 2 mg/day until patients showed evidence of a response or extrapyramidal symptoms. MRI scans were analyzed using a computerized volumetric approach to yield estimates of cerebrospinal fluid (CSF), gray-matter and white-matter volumes. Improvement in positive and negative symptoms after 1 week of treatment was significantly correlated with cortical gray-matter volumes. Those patients who were maintained on 2 mg/day of haloperidol had greater cortical gray-matter volume than those who were treated with higher doses. The severity of structural brain abnormalities at the onset of psychosis may contribute to individual variation in response to antipsychotic medication. It remains to be determined whether the degree to which particular domains of symptomatology can improve is related to the severity of structural brain pathology in specific brain regions.

Deficits in gray matter volume are present in schizophrenia but not bipolar disorder

Studies using magnetic resonance (MR) imaging have provided strong evidence that patients with schizophrenia as a group have structural brain abnormalities, including enlarged ventricles and sulci as well as smaller cortical gray matter volumes. This study was undertaken to investigate whether the brain abnormalities found in schizophrenia could be distinguished from those seen in bipolar disorder. The MR scans of 23 patients with schizophrenia were compared to those of 17 healthy community volunteers and 14 patients with bipolar disorder. Images were processed using computer-based image processing techniques to generate quantitative measures of cerebrospinal fluid (CSF), gray matter and white matter volumes. Compared to the community volunteers, the schizophrenia group had larger total CSF volumes while the bipolar group had larger ventricles. Smaller cortical gray matter volumes were found in the schizophrenia group, but not in the bipolar group. The schizophrenia group had regional deficits in gray matter volumes in comparison with both the community volunteers and the bipolar group. These findings suggest that the brain tissue abnormalities found in schizophrenia and bipolar disorder may be distinguishable using MR imaging.

A longitudinal magnetic resonance imaging study of brain changes in adolescents with anorexia nervosa

OBJECTIVE

To assess whether the cerebral gray and white matter volume deficits described in patients with anorexia nervosa (AN) are fully reversible with weight rehabilitation.

DESIGN

A prospective cohort study using magnetic resonance imaging to examine the brains of female adolescents after weight recovery from AN.

SETTING

An adolescent eating disorder program located in a tertiary care children's hospital.

PARTICIPANTS

Of 13 patients who underwent a previous magnetic resonance imaging study at a low weight, 6 patients were weight recovered and underwent rescanning. All brain measures were corrected for the effects of intracranial volume and age, based on a regression analysis of a group of 34 healthy female control subjects. Scans from the patients with AN were also compared with scans from an age-matched subset of 16 healthy female controls.

MAIN OUTCOME MEASURES

White matter volumes, gray matter volumes, and cerebrospinal fluid volumes in the weight-recovered AN group.

RESULTS

Quantitative analysis showed that white matter and ventricular cerebrospinal fluid volumes changed significantly (P = .03 for both) on weight recovery from AN. The weight-recovered patients had significant gray matter volume deficits (P = .01) and elevated cerebrospinal fluid volumes (P = .005) compared with those of the age-matched controls. They no longer had significant (P = .30) white matter volume deficits.

CONCLUSION

The finding of persistent gray matter volume deficits in patients who have recovered their weight after AN suggests an irreversible component to the structural brain changes associated with AN, in addition to a component that resolves on weight recovery.

Cerebral gray matter volume deficits after weight recovery from anorexia nervosa

BACKGROUND

Structural changes have been observed in the brains of low-weight patients with anorexia nervosa (AN), including increased cerebrospinal fluid (CSF) volumes and decreased gray matter and white matter volumes. We hypothesized that subjects who are weight-recovered from AN would show elevated CSF volumes and reduced gray matter volumes compared with controls.

METHODS

We used magnetic resonance imaging to compare the brains of 12 subjects who are weight-recovered from AN (time since weight recovery, 1-23 years) with those of 18 healthy control subjects and 13 low-weight patients with AN. Axial, dual-echo scans of the whole brain were segmented into gray matter, white matter, and CSF compartments by means of a computerized volumetric approach. Brain measures were corrected for the significant effects of intracranial volume and age, based on regression analysis of a larger group of 30 healthy female controls.

RESULTS

Tests showed that the weight-recovered group had significantly greater CSF volumes and smaller gray matter volumes than the control group. By comparison with low-weight patients, the weight-recovered subjects had significantly smaller CSF volumes and significantly larger gray matter and white matter volumes. In the weight-recovered group, neither the CSF elevations nor gray matter deficits were correlated with the length of time since weight recovery.

CONCLUSIONS

The persistent gray matter volume deficits in subjects who are weight-recovered from AN suggest that there may be an irreversible component to the brain changes associated with the illness. The neuropathological features of this irreversible component have yet to be characterized.

Relationship between negative symptoms in chronic schizophrenia and neuroleptic dose, plasma levels and side effects

The negative symptoms of schizophrenia are often difficult to distinguish from the side effects of antipsychotic medication. In this study, we tried to clarify this issue by studying a group of patients in a clinic setting where a wide range of antipsychotic doses were being prescribed. Thirty-one patients meeting DSM-III-R criteria for schizophrenia or schizoaffective disorder were studied. Clinical ratings were carried out to assess the positive and negative symptoms of schizophrenia, parkinsonism, akathisia and tardive dyskinesia. Plasma levels were also measured for the majority of patients. Antipsychotic plasma levels were found to be highly correlated with dose. Antipsychotic dose and plasma levels were not correlated with the severity of negative symptoms, akathisia or parkinsonism. However, the severity of positive symptoms and tardive dyskinesia were positively correlated with both dose and plasma level. These findings do not support the hypothesis that higher doses of antipsychotic medication are associated with more severe negative symptoms.

Patterns of content, contextual, and working memory impairments in schizophrenia and nonamnesic alcoholism

This study used tests of content memory (item recognition of words and abstract designs), context memory (order recognition of verbal and nonverbal items), and working memory (recognition at a short retention interval) to examine patterns of performance in 27 schizophrenic patients, 52 chronic alcoholic patients, and 66 healthy control participants. When performance was age- and IQ-adjusted the schizophrenia group was significantly impaired in item and order recognition of verbal and nonverbal material; the alcoholic group was impaired only in order recognition for both material types. Item- and order-recognition deficits in the schizophrenia group were greatest at the shortest retention intervals, a pattern previously observed in patients with Parkinson's disease, suggesting a prominence of a working memory deficit in schizophrenia.

The D2 receptor occupancy profile of loxapine determined using PET

Positron emission tomography (PET) studies of typical neuroleptics suggest that 60% to 80% of striatal D2 occupancy may be sufficient for optimal clinical treatment of psychosis. Therefore, striatal D2 occupancy may be used as an index to determine the optimal dose range. Toward this end, we determined the in vivo D2 profile of loxapine, using [11C]-raclopride and PET. Seven patients selected from a clinical population were scanned while taking steady-state oral loxapine from 10 to 100 mg/day. Their D2 receptor occupancy was estimated by comparing them to age-matched data from neuroleptic-naive patients. The D2 receptor occupancy ranged from 52% to 90%, and there was a very strong relationship between dose and D2 occupancy, suggesting that 15 to 30 mg/day of loxapine would produce, the putatively optimal, 60% to 80% striatal D2 blockade. This dose range is much lower than that used in most clinical settings and points to the potential efficacy of loxapine at lower doses.

Cerebral gray matter and white matter volume deficits in adolescent girls with anorexia nervosa

OBJECTIVES

This study was undertaken to determine whether the increased cerebrospinal fluid (CSF) volumes found in anorexia nervosa (AN) are the result of differences in gray matter or white matter volumes or both.

METHODS

Thirteen adolescent girls with AN who were receiving inpatient care at a tertiary-care university children's hospital and eight healthy female control subjects were studied by using magnetic resonance imaging. Images were processed by means of software developed to classify all pixels as either CSF, gray matter, or white matter. Pixels of each class were then summed across all sections.

RESULTS

The AN group had larger total CSF volumes in association with deficits in both total gray matter and total white matter volumes. Lowest reported body mass index was inversely correlated with total CSF volume and positively correlated with total gray matter volume. Urinary free cortisol levels were positively correlated with total CSF volume and inversely correlated with central gray matter volume.

CONCLUSIONS

These findings add support to the view that the brain abnormalities found in AN are in large part the result of the effects of the illness. The extent to which these differences in gray matter and white matter volumes are reversible with recovery remains to be established.

Cortical gray matter volume deficits in schizophrenia: a replication

We sought to replicate an earlier finding of widespread deficit in cortical gray matter in schizophrenia by testing new samples of 22 schizophrenic patients and 27 controls between the ages of 21-46 years. Brain values for both patients and controls were standardized against age and head size norms derived from a larger control group (n = 73) spanning a wider age range (21-70). Compared to the new age-matched controls, the new schizophrenic sample showed a deficit in gray matter volume affecting the cortex as a whole and enlargement of the lateral and third ventricles. Thus, widespread cortical gray matter deficit is a replicable feature of the brain dysmorphology of schizophrenia in young to middle-aged men.

Cognitive and motor impairments are related to gray matter volume deficits in schizophrenia

This study examined whether the neuropsychological deficits observed in patients with schizophrenia were related to cortical gray matter volume deficits in these patients. All subjects were men and included 34 patients with DSM-III-R Schizophrenia and 47 age-matched healthy controls. Subjects received a battery of 21 tests, assessing four different functional domains: executive functions, short-term memory and production, declarative memory, and motor ability. MRI volumes were corrected for normal variation in head size and age, and neuropsychological test scores were corrected for normal variation in age. The schizophrenic group had significantly smaller cortical gray matter volumes (p < .05) and lower test scores in all functional domain than the control group (p = .0001). Within the schizophrenic group, lower scores in each domain were significantly correlated with smaller total cortical gray matter volumes; however, no predictable relationships were observed between neuropsychological test performance and the volumes of specific cortical regions.

The D2 dopamine receptor occupancy of risperidone and its relationship to extrapyramidal symptoms: a PET study

Risperidone is a recently introduced neuroleptic distinguished by a decreased incidence of extrapyramidal side effects (EPS). The mechanism of its low EPS is unclear. Since it has been shown that EPS is related to the level of D2 receptor occupancy, we studied nine patients receiving 2-6 mg/day of risperidone using [11C]-raclopride PET scans in order to determine the in vivo D2 receptor binding characteristics of risperidone. The mean level of receptor occupancy was 66% at 2 mg; 73% at 4 mg; and 79% at 6 mg. Three patients, those with the highest receptor occupancies, exhibited mild EPS, though none required anitparkinsonian medications. Our results suggest that at doses of 4-6 mg the in vivo D2 receptor occupancy of risperidone is similar to that of typical neuroleptics and higher than that of clozapine. This would suggest that the EPS benefits of risperidone cannot be explained by a low D2 binding but may be related to its high 5-HT2 affinity. However, the emergence of EPS at higher levels of D2 receptor occupancy, in this study and in previous clinical trials, would suggest that risperidone's high 5-HT2 affinity provides only a relative protection from EPS. And once the D2 occupancy exceeds a certain threshold this 'relative' 5-HT2-mediated protection from EPS may be lost.

A deficit profile of executive, memory, and motor functions in schizophrenia

This study examined the neuropsychological deficits associated with schizophrenia and the interrelationships among multiple dissociable cognitive and motor functions. The tests were selected for their previously demonstrated sensitivity to circumscribed brain pathology and included four functional domains: executive functions, short-term memory and production, motor ability, and declarative memory. Each test composite was divided according to verbal versus nonverbal material or left- versus right-hand performance; this distinction permitted functions principally subserved by the left or right cerebral hemispheres to be tested separately. Data reduction was theoretically driven by the test selection and was achieved first by standardizing the scores of each test for age-related differences observed in the normal control group, and then by calculating test composite scores as an average of the age-corrected Z-scores of the tests comprising a functional composite. The schizophrenic group was impaired equivalently on all composites for both cerebral hemispheres; on average, the Z-scores of the patients were 1 standard deviation below those of the control group. The cognitive test composite scores were highly intercorrelated but showed only weak associations with motor ability. Multiple regression analyses suggested that symptom severity was a significant predictor of the Declarative Memory and Short-Term Memory/Production composite scores after accounting for disease duration, whereas disease duration uniquely contributed to the Executive Functions composite scores after controlling for symptom severity. Even though the schizophrenics as a group showed an equivalent level of deficit across all test composites, 1) the deficits were associated with different aspects of psychiatric symptomatology, 2) the motor deficit was independent of the cognitive deficits, and 3) each neuropsychological domain contributed independently to the deficit pattern. Thus, what appears to be a generalized functional deficit in schizophrenia may actually be, at least in part, combinations of multiple specific deficits.

The role of the left prefrontal cortex in verbal processing: semantic processing or willed action?

This study was designed to test the various proposed explanations (semantic processing, willed action, production of a spoken response) for the unilateral activation of the left prefrontal cortex noted in PET studies of verbal processing. Twenty subjects underwent 15O-water PET scans while undertaking a lexical task (detecting the letter 'a' in visually presented words) and a semantic task (categorizing nouns into living/non-living). The semantic task resulted in a significant unilateral left dorsolateral prefrontal activation. This finding suggests that the left inferior prefrontal cortex is the anatomical region involved in 'working with meaning', and that the activation does not reflect willed action, is not task-specific and is not attributable to the requirements of a spoken response.

A quantitative magnetic resonance imaging study of changes in brain morphology from infancy to late adulthood

OBJECTIVE

To model in vivo the dynamic interrelations of head size, gray matter, white matter, and cerebrospinal fluid (CSF) volumes from infancy to old age using magnetic resonance imaging (MRI).

DESIGN

Cross-sectional, between-subjects using an age-regression model.

SETTING

A Veterans Affairs medical center and community hospitals.

PARTICIPANTS

There were 88 male and female subjects aged 3 months to 30 years whose clinical MRI film had been read as normal and 73 healthy male volunteers aged 21 to 70 years who had an MRI performed specifically for this study.

MAIN OUTCOME MEASURES

These MRI data were quantified using a semiautomated computer technique for segmenting images into gray matter, white matter, and CSF compartments. The cortex was defined geometrically as the outer 45% on each analyzed slice, and the volumes of cortical white matter, gray matter, and CSF were computed. Subcortical (ventricular) CSF volume was computed for the inner 55% of each analyzed slice.

RESULTS

In the younger sample, intracranial volume increased by about 300 mL from 3 months to 10 years. The same patterns of change in volume of each compartment across the age range were seen in both sexes: cortical gray matter volume peaked around age 4 years and decreased thereafter; cortical white matter volume increased steadily until about age 20 years; cortical and ventricular CSF volumes remained constant. In the older sample, brain volumes were statistically adjusted for normal variation in head size through a regression procedure and revealed the following pattern: cortical gray matter volume decreased curvilin-early, showing an average volume loss of 0.7 mL/y, while cortical white matter volume remained constant during the five decades; complementary to the cortical gray matter decrease, cortical CSF volume increased by 0.6 mL/y and ventricular volumes increased by 0.3 mL/y.

CONCLUSIONS

These patterns of growth and change seen in vivo with MRI are largely consistent with neuropathological studies, as well as animal models of development, and may reflect neuronal progressive and regressive processes, including cell growth, myelination, cell death, and atrophy.

Volumetric MRI assessment of temporal lobe structures in schizophrenia

This magnetic resonance imaging (MRI) study was designed to investigate whether patients with schizophrenia have focal or lateralized deficits in the volumes of temporal lobe structures. Estimated volumes of the temporal lobes, hippocampi, superior temporal gyri, lateral ventricles, third ventricle, temporal horns of the lateral ventricles, and a frontal-parietal reference area (FPRA) were quantified for each hemisphere. The schizophrenic group had less gray matter (GM) in the temporal lobes and the FPRA relative to controls. Ventricular volumes were significantly larger in the schizophrenic group, as was cerebrospinal fluid (CSF) volume for temporal lobe sulci. No significant differences in hippocampal volumes emerged between groups. The magnitude of GM deficit was not greater in the temporal lobes relative to the FPRA. These results confirm the presence of bilateral GM volume deficits of the temporal lobes in schizophrenia but do not support the hypothesis that structural changes preferentially affect the temporal lobes or the left cerebral hemisphere.

Factors of the Wisconsin Card Sorting Test as measures of frontal-lobe function in schizophrenia and in chronic alcoholism

The purpose of this study was to examine the factor structure of the Wisconsin Card Sorting Test (WCST). The scores of 22 patients with schizophrenia, 20 patients with chronic alcoholism, and 16 normal control subjects were entered into a principal components analysis, which yielded three factors: Perseveration, Inefficient Sorting, and Nonperseverative Errors. WCST performance of seven patients with lesions invading the dorsolateral prefrontal cortex, available from another study, provided criterion validity for the Perseveration factor and, less strongly, for the Inefficient Sorting factor. Two patterns of performance characterized the three patient groups: the schizophrenic group and frontal lobe group had the highest Perseveration factor scores, whereas the alcoholic group had the highest Inefficient Sorting scores; the Nonperseverative Errors factor showed no significant group differences. Construct validity of these factors involved assessing, in all but the frontal group, the degree of overlap (convergent validity) and separation (discriminant validity) of each WCST factor with scores from tests of other cognitive functions. The convergent and discriminant validity of the Perseveration factor, but not the remaining two factors, received support only within the group of schizophrenic patients.