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R W Buchanan

Publications and source records attributed to R W Buchanan.

At least 55 records · Page 3Linked to original sources
PubMed1997

Visual information-processing impairments in deficit and nondeficit schizophrenia.

OBJECTIVE: Previous studies of covert visuospatial attention in schizophrenia suggest a subtle form of right hemispatial neglect in acutely ill patients but not in chronic, stable patients. Because of previous work documenting various visual information-processing abnormalities in deficit schizophrenia, the authors investigated whether the deficit/nondeficit categorization would help clarify the presence of visual attentional asymmetries in schizophrenia. METHOD: Performance on a covert visuospatial attention task was examined in clinically stable outpatients with schizophrenia (17 in a deficit subgroup and 28 in a nondeficit subgroup) and 25 normal subjects. Peripheral cue and central cue versions of the covert visuospatial attention task, at 100-, 200-, and 800-msec intervals between cue and target, were administered a week apart. RESULTS: The nondeficit patients exhibited a significant and abnormal asymmetry, with slower reaction time to targets presented in the right visual field than in the left visual field. This right visual field disadvantage was found with both versions of the task, but only at the 100-msec cue-target interval. The deficit patients were slowest in overall reaction time but, similar to the normal subjects, showed no asymmetry. CONCLUSIONS: The results are consistent with slower visual information processing in the left compared to the right cerebral hemisphere in nondeficit schizophrenia. This finding cannot be accounted for by differences between the deficit and nondeficit subgroups in demographic characteristics, chronicity, or medication effects, nor is it secondary to generalized cognitive impairment.

Adolescent↗
PubMed1996

Clozapine response and the 5HT2C Cys23Ser polymorphism.

The presence of the 5HT2C receptor allele, Ser23, has recently been reported to predict favorable response to the antipsychotic drug, clozapine. This finding is of interest as Ser23, compared with the more abundant Cys23, alters pharmacological characteristics of the receptor and therefore may provide insights into the mechanism of action of antipsychotic drugs. We determined 5HT2C receptor genotype at the Cys23Ser locus in 66 subjects participating in double-blind studies of clozapine. There was no relationship between Ser23 and clozapine response (p = 0.30, Fisher's exact) nor was there any effect of Ser23 upon absolute levels of psychiatric symptoms after 10 weeks of clozapine treatment (t = -0.57, p = 0.57). These data suggest that this 5HT2C receptor polymorphism is not associated with clozapine response.

Alleles↗
PubMed1996

Does pursuit abnormality in schizophrenia represent a deficit in the predictive mechanism?

Although an abnormality of smooth pursuit eye movement has been consistently noted in schizophrenia, the underlying ocular motor pathophysiology is unknown. It is unclear whether the abnormality represents deficits in processing of information provided by the moving target, generation of pursuit eye movements, or other ocular motor and related cognitive processes. To evaluate the ability to process information provided by a moving target, saccadic accuracies were studied in step-ramp and single step tasks. Schizophrenic (with and without tardive dyskinesia [TD]) and normal subjects made equally accurate initial corrective saccades to the moving target. Thus, when the target jumped and then smoothly moved (creating a position and a velocity error on the retina), the patients were able to process retinal motion information and generate a normally accurate saccadic response. After the initial corrective saccade, both groups followed the target with a combination of pursuit eye movements and occasional catch-up saccades. During this period, the retinal velocity error is minimal because the eye approximates the target motion, and the major source of target motion information both for the smooth pursuit and saccadic responses is extra-retinal (i.e., predictive mechanism). The accuracies of catch-up saccades were significantly lower in the schizophrenic patients than in the normal subjects. During this period, overall pursuit performance, measured by pursuit gain, was also significantly worse in the patients. Accuracies of subsequent catch-up saccades, but not initial corrective saccades, significantly predicted the pursuit gain. Low pursuit gain was associated with high numbers of saccades per time spent in pursuit, which were similar in both schizophrenic subgroups (i.e., with and without TD), but were only significantly higher in the patients with TD than in the normal subjects. These preliminary data suggest that schizophrenic patients are able to process retinal motion information but have difficulties in using extra-retinal motion information to generate an appropriate saccadic response.

Adult↗
PubMed1996

Catching up on schizophrenia. The Fifth International Congress on Schizophrenia Research, Warm Springs, Va, April 8-12, 1995.

It is axiomatic that the diversity and ingenuity of strategies in the study of schizophrenia bear testimony to the complexity of this disorder. Accordingly, the opportunity for investigators of diverse interests to share their latest findings and be informed of developments in key areas of science is critical to advance our understanding of schizophrenia. Nearly 700 investigators from around the world gathered at Warm Springs, Va, to present their data at the Fifth International Congress on Schizophrenia Research (April 8-12, 1995). This 5-day conference, held every other year alternating with the European Winter Workshop on Schizophrenia, is co-organized by S. Charles Schulz, MD, Case Western Reserve University, Cleveland, Ohio, and Carol Tamminga, MD, Maryland Psychiatric Research Center, University of Maryland at Baltimore. Drs Schulz and Tamminga first held the Congress in 1987 in Clearwater, Fla, with 170 investigators presenting. The Congress has flourished since then and is now the largest research meeting devoted solely to schizophrenia. The Congress organizers, the program coordinator (Jeffrey Lieberman, MD, Hillside Hospital, Glen Oaks, NY), and the Congress coordinator (Susan Nusbaum, Maryland Psychiatric Research Center) are congratulated on the success of this event and its contribution to fostering initiatives and collaborations within schizophrenia research.

Female↗
PubMed1996

The deficit syndrome in the DSM-IV Field Trial. Part II. Depressive episodes and persecutory beliefs.

Patients with the deficit syndrome are remarkable for their decrease in interest in social relationships, suggesting they have an abnormality in those brain regions controlling social behavior and social cognition. To further assess social behavior and social cognition in this group of patients, we examined the relationships among three aspects of the psychopathology: suspiciousness; major depressive episodes; and the deficit syndrome. These features of psychopathology were examined in two clinical samples: stable outpatients from a research clinic (the MPRC sample), and patients in the DSM-IV Field Trial. In both samples, patients with history of a depressive episode had more severe suspiciousness than those without such a history; other psychotic symptoms were not associated with depressive episodes. In the MPRC sample, patients with the deficit syndrome exhibited less severe suspiciousness than nondeficit patients; in the Field Trial sample, this same comparison had a nonsignificant trend in the same direction. In the Field Trial sample, patients with the deficit syndrome also had less severe delusions with a predominantly social content than did nondeficit patients. These findings suggest suspiciousness is a risk factor for major depression in schizophrenia, and that the decreased interests in social relationships exhibited by deficit syndrome patients is reflected in the content of their delusions.

Adult↗
PubMed1996

Negative symptoms: diagnosis, treatment and prognosis.

The concept of negative symptoms is derived from Kraeplin's description of the dissolution of the personality in patients with schizophrenia. Negative symptoms may be either primary, or secondary to positive symptoms, antipsychotic side effects, dysphoric affect and environmental deprivation. Primary negative symptoms represent core features of the illness, and have been termed deficit symptoms. The differentiation of primary from secondary negative symptoms has important treatment implications, as treatment approaches vary greatly for the different types of negative symptoms. Specific pharamacological and psychosocial treatments are available for secondary negative symptoms. However, to date, there are no known effective treatments for primary negative symptoms. The importance of developing effective treatments for primary negative symptoms is underscored by the relationship of these symptoms to poor social, occupational, and global outcome.

Antipsychotic Agents↗
PubMed1996

Clozapine conflict.

Explore the source record for details and available documents.

Antipsychotic Agents↗
PubMed1996

Fluoxetine augmentation of clozapine treatment in patients with schizophrenia.

OBJECTIVE: The authors examined the efficacy of fluoxetine augmentation of clozapine treatment response in schizophrenic outpatients who, despite adequate treatment with clozapine, continued to exhibit persistent positive or negative symptoms. METHOD: Thirty-three patients completed on 8-week, double-blind, parallel-groups comparison of adjunctive fluoxetine and placebo. RESULTS: There were no significant differences in positive, negative, depressive, or obsessive-compulsive symptoms between patients given adjunctive fluoxetine or placebo. CONCLUSIONS: These results suggest that fluoxetine is not effective in augmenting clozapine treatment response.

Adult↗
PubMed1996

Differential effect of clozapine on weight: a controlled study.

OBJECTIVE: This study examined whether clozapine induces more weight gain than haloperidol and whether weight gain is related to clinical improvement. METHOD: The weight and symptoms of 39 outpatients with schizophrenia who were randomly assigned to double-blind treatment with either clozapine or haloperidol were assessed. The weight and symptoms of 33 of the patients who chose to take clozapine during a 1-year follow-up after the study ended were also assessed. RESULTS: The patients treated with clozapine gained significantly more weight over baseline (7%) than the haloperidol-treated patients (1%). Weight gain was not significantly correlated with improvements in either positive or negative symptoms. Fifty-eight percent of the patients followed for 1 year gained at least 10% over their baseline weight. CONCLUSIONS: Weight gain is an important side effect of clozapine and is unrelated to the drug's differential antipsychotic efficacy.

Ambulatory Care↗
PubMed1996

Association of abnormal smooth pursuit eye movements with the deficit syndrome in schizophrenic patients.

OBJECTIVE: The authors' goal was to test the hypothesis that abnormal smooth pursuit eye movements in schizophrenic patients are associated with the deficit syndrome. METHOD: The eye movements of 24 normal comparison subjects, 32 patients with nondeficit schizophrenia, and 11 patients with deficit schizophrenia were tested with infrared oculography using foveapetal step-ramp targets. RESULTS: The group of schizophrenic patients had normal latency to pursuit onset, abnormally decreased open-loop acceleration and abnormally decreased velocity during the periods of closed-loop acceleration and steady-state pursuit. The subgroup of schizophrenic patients with the deficit syndrome had particularly poor performance during the periods of open- and closed-loop acceleration. CONCLUSIONS: Patients with schizophrenia have abnormal smooth pursuit eye movements in response to a step-ramp stimulus, and the defects are particularly pronounced in patients with the deficit syndrome. Abnormal smooth pursuit eye movements in schizophrenia and related disorders have been consistently linked with primary and enduring negative symptoms.

Adult↗
PubMed1995

Borna disease virus and schizophrenia.

The development of a new serological assay method to detect antibodies in human sera recognizing Borna disease virus (BDV) proteins and a clinical pilot study are presented. Psychiatric patients from a schizophrenia research clinic in Baltimore, Maryland, were examined for antibodies to BDV antigen with traditional indirect immunofluorescence assays (IFA) that used both single and double labeling techniques and also with a Western blot assay capable of detecting antibodies to the three BDV proteins from a human neuroblastoma cell line. Thirteen of 90 (14.4%) patients and 0/20 control subjects had antibodies that recognized more than one BDV protein on the Western blot. Three patients had antibodies that recognized all three BDV proteins. Magnetic resonance imaging assessments of the volume of the putamen (with controls for total cranial volume) differentiated BDV+ from BDV- patients, and there were trend differences for bilateral amygdalae and the left amygdala-hippocampal process. We conclude that: (1) the Western blot assay is superior to IFA assays in BDV serology studies, (2) detection of antibodies to more than one BDV protein is a useful working criterion for seropositivity, (3) the 14.5 kDa BDV protein is 10 times more predictive of seropositivity than either the 38/40 kDa or the 24 kDa protein, (4) there is tentative evidence for a schizophrenia-control difference in the prevalence of anti-BDV antibodies, and (5) it is likely that there are neuroanatomical/behavioral features that differentiate seropositive from seronegative schizophrenic patients.

Adult↗
PubMed1995

Prodromal symptoms vs. early warning signs and clinical action in schizophrenia.

The term "prodromal symptoms" has traditionally referred to prepsychotic changes in thought, affect, and cognition that precede the initial onset of schizophrenia. Recently, however, the term has been extended into a clinical action context to refer to the early warning signs (EWS) of impending relapse in patients already diagnosed as having schizophrenia. However, recent reports reviewed by Norman and Malla (1995, this issue) use a narrow definition of prodromal symptoms and question their use in the clinical action context. We argue that the dual use of the term "prodromal symptoms" has led to conceptual confusion and to the impression that EWS cannot be used effectively for clinical action. The ability to base clinical action on EWS is central to schizophrenia therapeutics and is the cornerstone of pharmacological strategies based on early intervention. Our review of the evidence suggests that the effective clinical use of EWS depends on (1) the inclusion of both psychotic and nonpsychotic symptoms as EWS; (2) the use of clinician judgment in combination with predefined symptom changes to define the occurrence of EWS; (3) frequent clinical visits; and (4) the use of family or caregiver informants. We therefore suggest that, in the clinical action context, the terminology "early warning signs of impending relapse" should be used instead.

Anti-Anxiety Agents↗
PubMed1995

Clozapine: efficacy and safety.

Clozapine (Clozaril) represents the first major advance in the pharmacological treatment of schizophrenia since the introduction of antipsychotics into clinical practice in the 1950s. Studies consistently support its efficacy for reducing positive symptoms in acutely psychotic patients and in treatment-resistant patients, for preventing positive symptom exacerbations as a maintenance treatment, and for reducing symptoms of hostility and violence. There is evidence to suggest that clozapine may improve social and occupational functioning and quality of life and may reduce affective symptoms, hospitalizations, secondary negative symptoms, and tardive dyskinesia. Its most significant side effects include agranulocytosis, seizures, weight gain, hypotension and tachycardia, sedation, and perhaps rebound psychosis (with abrupt discontinuation of medication).

Antipsychotic Agents↗
PubMed1995

Patient response and resource management: another view of clozapine treatment of schizophrenia.

OBJECTIVE: Issues in clozapine treatment were considered in terms of implications for resource management. METHOD: A critical review of the literature on time course and pattern of response to clozapine was used to address treatment of negative symptoms, late responders, and extent of clinical benefit in ordinary settings. RESULTS: Superior efficacy of clozapine for partial and poor neuroleptic responders is observed in about one-half of the cases. Response is rapid once a therapeutic dose is reached, and the data do not support the proposition that some patients first respond only after 3-12 months of therapy. The cumulative benefit over several months of treatment and the broad range of symptoms involved in response are similar to those for typical neuroleptic drugs, suggesting that clozapine's superiority is based on greater effectiveness rather than a unique profile of treatment effects. Clozapine appears to be effective for secondary, but not primary, negative symptoms. Modal response is moderate, and extensive rehabilitation and clinical services are required to substantially enhance functional outcome. CONCLUSIONS: Many more patients merit trials with clozapine. Economic costs and adverse drug effects can be minimized by selecting patients most likely to benefit and discontinuing clozapine treatment when benefit is not observed within 2-4 months. Appropriate patients include 1) those with good responses to typical neuroleptics who experience substantial adverse effects and 2) those whose disorders respond poorly to standard neuroleptics and are defined by psychotic symptoms, thought disorder, and hostility. Treatment of primary negative symptoms is not supported by the current experimental data.

Antipsychotic Agents↗
PubMed1995

New diagnostic issues in schizophrenic disorders.

The evolution of our understanding of schizophrenia has provided new concepts that substantially alter answers to questions such as age of onset, distribution by sex, and treatment response. Moreover, these new concepts offer heuristic advantages in etiopathophysiological study designs and permit investigators to address key sources of artifact. We discuss the unitary versus the clinical syndromal concept of schizophrenia and describe the implications of the latter with regard to the study of schizophrenia. We also present a heuristic tripartite division of schizophrenic symptoms for reducing syndromal heterogeneity.

Age of Onset↗
PubMed1994

The comparative efficacy and long-term effect of clozapine treatment on neuropsychological test performance.

Previous studies have suggested that clozapine may improve neuropsychological test performance. The current study was designed to examine the comparative efficacy and the long-term effect of clozapine (versus haloperidol), on neuropsychological test performance. Neuropsychological measures of executive/attention, visuospatial, and memory function were administered to schizophrenic patients at baseline, at the end of a 10-week double-blind study, and after 1 year of open clozapine treatment. Symptoms and function ratings were obtained at the same time points. The 10-week double-blind study revealed significant group-by-time interactions for two measures: Categorical Fluency and WAIS-R Block Design. At the end of 1 year of open treatment there were significant improvements in Verbal Fluency, Mooney Faces Closure, and WAIS-R Block Design performance, and trend improvements in Stroop Color-Word Interference, Category Fluency, and WMS-R Logical Memory performance. Improvements in neuropsychological performance were unrelated to symptom changes. Change in selected neuropsychological measures were significantly correlated with improvement in quality of life. The results suggest that long-term clozapine treatment may have beneficial effects on a broad range of cognitive functions.

Adult↗