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Biomedical subjects

Jan Volavka

Publications and source records attributed to Jan Volavka.

At least 19 recordsLinked to original sources
PubMed2004

COMT158 polymorphism and hostility.

The main study was designed primarily to compare the clinical effects of four antipsychotics in 157 patients with schizophrenia or schizoaffective disorder. The secondary genetic study, reported here, is based on a subset of 60 patients who consented to genotyping assays. Based on previous work with the catechol-O-methyltransferase (COMT) 158 polymorphism, we hypothesized that the Met-Met homozygotes would be more hostile than the heterozygotes and the Val-Val homozygotes. Hostility ratings at baseline were used to test this hypothesis. The Met-Met homozygotes (N = 7) were found to have significantly higher levels of hostility than the other patients (N = 53). The hypothesis was thus supported. The finding should be replicated in a larger sample.

Antipsychotic Agents↗
PubMed2004

The catechol-O-methyltransferase polymorphism: relations to the tonic-phasic dopamine hypothesis and neuropsychiatric phenotypes.

Diverse phenotypic associations with the catechol-O-methyltransferase (COMT) Val158Met polymorphism have been reported. We suggest that some of the complex effects of this polymorphism be understood from the perspective of the tonic-phasic dopamine (DA) hypothesis. We hypothesize that the COMT Met allele (associated with low enzyme activity) results in increased levels of tonic DA and reciprocal reductions in phasic DA in subcortical regions and increased D1 transmission cortically. This pattern of effects is hypothesized to yield increased stability but decreased flexibility of neural network activation states that underlie important aspects of working memory and executive functions; these effects may be beneficial or detrimental depending on the phenotype, a range of endogenous factors, and environmental exigencies. The literature on phenotypic associations of the COMT Val158Met polymorphism is reviewed, highlighting areas where this hypothesis may have explanatory value, and pointing to possible directions for refinement of relevant phenotypes and experimental evaluation of this hypothesis.

Animals↗
PubMed2004

Overt aggression and psychotic symptoms in patients with schizophrenia treated with clozapine, olanzapine, risperidone, or haloperidol.

The subjects were 157 treatment-resistant inpatients diagnosed with chronic schizophrenia or schizoaffective disorder. They were randomly assigned to treatment with clozapine, olanzapine, risperidone, or haloperidol in a 14-week, double-blind trial. Incidents of overt aggression were recorded and their severity was scored. The Positive and Negative Syndrome Scale was administered. Atypical antipsychotics showed an overall superiority over haloperidol, particularly after the first 24 days of the study when the dose escalation of clozapine was completed. Once an adequate therapeutic dose of clozapine was reached, it was superior to haloperidol in reducing the number and severity of aggressive incidents. Patients exhibiting persistent aggressive behavior showed less improvement of psychotic symptoms than the other patients. There was an interaction between aggressiveness, medication type, and antipsychotic response: risperidone and olanzapine showed better antipsychotic efficacy in patients exhibiting less aggressive behavior; the opposite was true for clozapine. Clozapine appears to have superior antiaggresive effects in treatment-resistant patients; this superiority develops after the patient has been exposed to an adequate dose regimen.

Aggression↗
PubMed2004

Catechol O-methyltransferase Val158Met polymorphism in schizophrenia: differential effects of Val and Met alleles on cognitive stability and flexibility.

OBJECTIVE: The catechol O-methyltransferase (COMT) Val158Met polymorphism has been associated with cognitive and behavioral phenotypes in schizophrenia. Whether COMT genotype is beneficial may depend on phenotype definition. The authors examined the effects of COMT genotype on a task that distinguishes imitation from reversal learning. They hypothesized that the Val and Met alleles would be associated with deficits in imitation learning and reversal learning, respectively. METHOD: Twenty-six patients with schizophrenia and schizoaffective disorder completed a task requiring alternation between imitation and reversal rules. RESULTS: Met homozygotes showed better acquisition of the imitation rule but greater deficit shifting from imitation to reversal. Val homozygotes had poorer imitation performance and slower reaction times. CONCLUSIONS: The Met allele, by increasing tonic dopamine, may promote cognitive stability but limit cognitive flexibility.

Adult↗
PubMed2004

Course of patients with histories of aggression and crime after discharge from a cognitive-behavioral program.

OBJECTIVE: Patients exhibiting aggressive or criminal behavior present a challenge to treaters and caregivers. After discharge from an inpatient facility, such patients are at high risk of rehospitalization and rearrest. A long-term behaviorally based cognitive skills program was developed and administered to a group of such high-risk inpatients. The authors report the results of a postdischarge follow-up of this group. METHODS: After patients entered the inpatient treatment program, their psychiatric and criminal histories were recorded, and a battery of psychological measures were administered, including IQ tests and the Hare Psychopathy Checklist. After discharge, multiple sources were used to obtain information about patients' outcomes. RESULTS: Eighty-five patients were followed for between six months and two years after discharge. Thirty-three of these patients (39 percent) remained stable in the community, 35 (42 percent) were rehospitalized, and 17 (20 percent) were arrested. Several variables that were ascertained before discharge predicted rehospitalization or arrest rates: comorbid antisocial personality disorder, higher score on the Psychopathy Checklist, history of arrests for violent crimes, and history of a learning disability. In addition, patients who developed substance use problems or did not adhere to medication treatment after discharge were more likely to be rehospitalized or arrested. CONCLUSIONS: Arrest rates were low compared with those observed in studies with similar populations. Although this outcome may be attributable to the treatment program, this naturalistic study could not prove that. The predictors of poor outcome may be used to develop a follow-up treatment program that focuses more resources on patients who are at the highest risk.

Adult↗
PubMed2004

Prolactin levels in schizophrenia and schizoaffective disorder patients treated with clozapine, olanzapine, risperidone, or haloperidol.

BACKGROUND: Prolactin levels are elevated to varying degrees by antipsychotics. Prolactin elevations may result in sexual and other adverse effects, and they may be related to antipsychotic effects. We used the data collected in a trial of antipsychotics to study the differential effect of these drugs on prolactin level, to explore the relation between clinical effects and prolactin level, and to determine the relationship between plasma levels of antipsychotics and prolactin level. METHOD: Treatment-resistant patients (133 men, 24 women) diagnosed with DSM-IV schizophrenia or schizoaffective disorder participated in a double-blind, randomized, 14-week trial comparing clozapine (N = 40), olanzapine (N = 39), risperidone (N = 41), and haloperidol (N = 37). Plasma levels of prolactin and antipsychotics were determined at baseline and at weeks 5, 8, 10, 12, and 14 during the trial. Clinical effects were measured with the Positive and Negative Syndrome Scale and the Extrapyramidal Symptom Rating Scale. Statistical analyses were limited to the 75 men for whom repeated prolactin levels were available. Data were gathered from June 1996 to December 1999. RESULTS: Risperidone caused significant elevation of prolactin levels (p <.05) that appeared to be dose-dependent. Clozapine and olanzapine were associated with decreases of prolactin, whereas haloperidol led to a minor, nonsignificant increase. Plasma olanzapine and prolactin levels were correlated. Prolactin levels were not related to clinical improvement or extrapyramidal side effects. CONCLUSION: Antipsychotics show major differences in their effects on prolactin, and risperidone has clearly the most robust effect.

Adult↗
PubMed2004

Effects of atypical antipsychotics on the syndromal profile in treatment-resistant schizophrenia.

BACKGROUND: There has been considerable support for the observation that atypical antipsychotics have a broader range of therapeutic effects than traditional antipsychotics. We are exploring whether this expanded clinical efficacy can also be seen in patients with treatment-resistant schizophrenia. METHOD: The subjects were 157 treatment-resistant inpatients diagnosed with DSM-IV schizophrenia or schizoaffective disorder. They were randomly assigned to treatment with clozapine, olanzapine, risperidone, or haloperidol in a 14-week double-blind trial and rated with a standard measure of clinical antipsychotic efficacy (Positive and Negative Syndrome Scale [PANSS]). Factor analysis at baseline and endpoint together with changes in 5 PANSS-derived factors were examined. Data were gathered from June 1996 to December 1999. RESULTS: The underlying PANSS factor structure, as indicated by the factor loadings, was essentially identical at baseline and endpoint. At baseline, the excitement factor was followed by the positive, negative, cognitive, and depression/anxiety factors, explaining 49.4% of the total variance. At endpoint, the positive factor was followed by the negative, excitement, cognitive, and depression/anxiety factors, explaining 55.5% of the total variance. The endpoint data indicated statistically significant (p <.05) improvements over time on the positive factor for all 3 atypicals, but not for haloperidol. The negative factor showed significant improvement for clozapine and olanzapine, with significant worsening for haloperidol. Clozapine, olanzapine, and risperidone were superior to haloperidol on the negative factor, while clozapine was also superior to risperidone. The cognitive factor showed significant improvement for all atypicals, as did the depression/anxiety factor. Only clozapine showed improvement on the excitement factor and was superior to both haloperidol and risperidone. CONCLUSIONS: Treatment with atypical antipsychotics did not substantially change the underlying PANSS 5-factor structure. However, antipsychotic treatment with all 3 atypical medications was associated with significant improvements on 3 of 5 syndromal domains (positive, cognitive, and depression/anxiety) of schizophrenia. Clozapine and olanzapine also showed improvement on the negative factor. Only clozapine was associated with improvement on the excitement domain. This finding confirms that atypicals are associated with improvement of an expanded spectrum of symptoms in treatment-resistant patients.

Adult↗
PubMed2003

Placebo or active control trials of antipsychotic drugs?

The placebo-controlled trial has been the standard method to demonstrate efficacy and safety of antipsychotic drugs. We reviewed the scientific and ethical advantages and disadvantages of the placebo-controlled trial and an alternative method, the active-control trial, focusing more specifically on the active-control noninferiority trial. Recent meta-analyses indicate that a therapeutic dose of second-generation antipsychotic will very likely be statistically superior to placebo in an adequate trial, and that the average improvement of schizophrenia symptoms in a placebo arm will be small. These findings strengthen the scientific and ethical justification for the active-control noninferiority trial. New drugs in the pharmacotherapy for schizophrenia are often claimed to differ from their marketed competitors in their safety profile rather than in antipsychotic efficacy. Thus, in many cases, it appears sufficient to demonstrate mere noninferiority (rather than superiority) of antipsychotic efficacy in comparison with a standard antipsychotic. The active-control noninferiority trial is suitable for such demonstration. Sample size requirements for various equivalence margins in noninferiority trials are provided. Scientific and ethical arguments should lead to a more frequent use of the active-control noninferiority trial design.

Antipsychotic Agents↗
PubMed2003

Changes in glucose and cholesterol levels in patients with schizophrenia treated with typical or atypical antipsychotics.

OBJECTIVE: The association of hyperglycemia and hypercholesterolemia with use of atypical antipsychotics has been documented in case reports and uncontrolled studies. The authors' goal was to assess the effects of clozapine, olanzapine, risperidone, and haloperidol on glucose and cholesterol levels in hospitalized patients with schizophrenia or schizoaffective disorder during a randomized double-blind 14-week trial. METHOD: One hundred fifty-seven patients with schizophrenia or schizoaffective disorder who were inpatients at four hospitals were originally included in the study. The 14-week trial consisted of an 8-week fixed-dose period and a 6-week variable-dose period. Planned assessments included fasting glucose and cholesterol, which were collected at baseline and at the end of the 8-week period and the following 6-week period. RESULTS: One hundred eight of the 157 patients provided blood samples at baseline and at least at one point after random assignment to clozapine, olanzapine, risperidone, or haloperidol during the treatment trial. Seven of these patients had diabetes; their glucose levels were >125 mg/dl at baseline. Data from 101 patients were used for statistical analyses. During the initial 8-week period there was an overall significant increase in mean glucose levels. There were significant increases in glucose levels at the end of the 8-week fixed-dose period for patients given clozapine (N=27) and those given haloperidol (N=25). The olanzapine group showed a significant increase of glucose levels at the end of the 6-week variable-dose period (N=22). Fourteen of the 101 patients developed abnormal glucose levels (>125 mg/dl) during the trial (six with clozapine, four with olanzapine, three with risperidone, and one with haloperidol). Cholesterol levels were increased at the end of the 8-week fixed-dose period for the patients given clozapine (N=27) and those given olanzapine (N=26); cholesterol levels were also increased at the end of the 6-week variable-dose period for patients given olanzapine (N=22). CONCLUSIONS: In this prospective randomized trial, clozapine, olanzapine, and haloperidol were associated with an increase of plasma glucose level, and clozapine and olanzapine were associated with an increase in cholesterol levels. The mean changes in glucose and cholesterol levels remained within clinically normal ranges, but approximately 14% of the patients developed abnormally high glucose levels during the course of their participation in the study.

Adult↗
PubMed2003

Characteristics of assaultive behavior among psychiatric inpatients.

OBJECTIVE: The purpose of this study was to assess the extent to which psychosis, disordered impulse control, and psychopathy contribute to assaults among psychiatric inpatients. METHODS: The authors used a semistructured interview to elicit reasons for assaults from assailants and their victims on an inpatient research ward. Video monitoring provided supplemental information to confirm participants' identities and activities before and during the assault. RESULTS: Consensus clinical ratings indicated that approximately 20 percent of the assaults in this sample were directly related to positive psychotic symptoms. Factor analysis revealed two psychosis-related factors, one related to positive psychotic symptoms and the other to psychotic confusion and disorganization, as well as a third factor that differentiated impulsive from psychopathic assaults. CONCLUSIONS: Information obtained from interviews with assailants can reveal the underlying causes of specific assaults. This information is potentially useful in the selection of rational antiaggressive treatment strategies.

Consensus↗
PubMed2002

Neurocognitive correlates of the COMT Val(158)Met polymorphism in chronic schizophrenia.

BACKGROUND: Neurocognitive deficits are recognized as a cardinal feature of schizophrenia, but the determinants of these deficits remain unknown. Recent reports have suggested that a functional polymorphism, Val(158)Met in exon III of the catechol-O-methyltransferase gene, shares approximately 4% variance with performance on the Wisconsin Card Sorting Test. These findings led to suggestions that the catechol-O-methyltransferase polymorphism may exert its effects by modulating prefrontal dopamine function, but few other neurocognitive measures have been examined, leaving open questions about phenotypic specificity. METHODS: We examined the effects of the catechol-O-methyltransferase Val(158)Met polymorphism in 58 individuals with chronic schizophrenia who completed a battery of 15 neurocognitive tests, which were reduced to four reliable neurocognitive domain scores. We examined the effects of genotype on these four domains and on global neurocognitive ability. RESULTS: The Met allele was associated with better performance in the Processing Speed and Attention domain, but not with other domain scores measuring executive and visuoperceptual functions, declarative verbal learning and memory, simple motor ability, or global neurocognitive function. Genotype shared approximately 11% of variance with Processing Speed and Attention scores, and approximately 2% of variance with Wisconsin Card Sorting Test scores. CONCLUSIONS: The findings provide independent support for the hypothesis that the catechol-O-methyltransferase Val(158)Met polymorphism influences neurocognitive function in schizophrenia, and suggest that the functional effects may be expressed on measures of Processing Speed and Attention. This information may prompt reconsideration of the "prefrontal dopamine" hypothesis and invites examination of a broader range of effects in efforts to refine the neurocognitive phenotype that is most relevant to variation in catechol-O-methyltransferase expression.

Adult↗
PubMed2002

Frontal white matter microstructure, aggression, and impulsivity in men with schizophrenia: a preliminary study.

BACKGROUND: Aggression and impulsivity may involve altered frontal white matter. METHODS: Axial diffusion tensor images were acquired in 14 men with schizophrenia using a pulsed gradient, double spin echo, echo planar imaging method. White matter microstructural measures (fractional anisotropy and trace) were calculated from these data. Regions of interest were placed in frontal white matter on four slices. Impulsivity was measured using the Motor Impulsiveness factor of the Barratt Impulsiveness Scale. Aggressiveness was measured using the Assaultiveness scale of the Buss Durkee Hostility Inventory and the Aggression scale of the Life History of Aggression. RESULTS: Lower fractional anisotropy in right inferior frontal white matter was associated with higher motor impulsiveness. Higher trace in these regions was associated with aggressiveness. CONCLUSIONS: Inferior frontal white matter microstructure was associated with impulsivity and aggression in men with schizophrenia. These results implicate frontal lobe dysfunction in aggression and certain aspects of impulsivity.

Adult↗
PubMed2002

Antipsychotic-induced weight gain and therapeutic response: a differential association.

This study investigated the association between antipsychotic-induced weight gain and therapeutic response to haloperidol and three commonly used atypical neuroleptic medications in schizophrenia and schizoaffective disorder. The subjects were 151 patients enrolled in a double-blind experiment with a duration of 14 weeks comparing the therapeutic efficacy of haloperidol (n = 36), clozapine (n = 38), olanzapine (n = 38), and risperidone (n = 39). Absolute and relative (%) gain in body weight and body mass index (BMI) was determined for the entire duration of the double-blind treatment period; therapeutic response was assessed by the total score and the individual subscales of the Positive and Negative Symptom Scale. Compared with the pretreatment baseline, results indicated that for olanzapine and clozapine, therapeutic response was closely related to an absolute and relative gain in weight and to a gain in BMI. No association between weight gain and therapeutic response was found for risperidone and haloperidol. These findings suggest that patients who are likely to have the maximal benefits of olanzapine or clozapine treatment for symptom alleviation are at the highest risk of a clinically significant increase in weight gain.

Adult↗
PubMed2002

Clozapine, olanzapine, risperidone, and haloperidol in the treatment of patients with chronic schizophrenia and schizoaffective disorder.

OBJECTIVE: The authors compared the efficacy and safety of three atypical antipsychotics (clozapine, olanzapine, and risperidone) with one another and with haloperidol in the treatment of patients with chronic schizophrenia or schizoaffective disorder. METHOD: In a double-blind trial, 157 inpatients with a history of suboptimal treatment response were randomly assigned to treatment with clozapine, olanzapine, risperidone, or haloperidol for 14 weeks (an 8-week escalation and fixed-dose period followed by a 6-week variable-dose period). RESULTS: Clozapine, risperidone, and olanzapine (but not haloperidol) resulted in statistically significant improvements in total score on the Positive and Negative Syndrome Scale. Improvements seen in total and negative symptom scores with clozapine and olanzapine were superior to haloperidol. The atypical drugs, particularly olanzapine and clozapine, were associated with weight gain. CONCLUSIONS: The effects of atypical antipsychotics in this population were statistically significant but clinically modest. The overall pattern of results suggests that clozapine and olanzapine have similar general antipsychotic efficacy and that risperidone may be somewhat less effective. Clozapine was the most effective treatment for negative symptoms. However, the differences among treatments were small.

Adolescent↗