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Biomedical subjects

J A Lieberman

Publications and source records attributed to J A Lieberman.

At least 145 records · Page 8Linked to original sources
PubMed1994

Clozapine dose in the United States and Europe: implications for therapeutic and adverse effects.

The report (1) provides an overview of clozapine doses used in trials conducted in Europe and the United States, (2) compares data on efficacy, and (3) compares side effects of clozapine from recent European and U.S. investigations. The reviewed European trials used a mean dose of 283.7 mg/day, while the mean dose in the U.S. studies was 444 mg/day. Even though the mean doses used in the United States are considerably higher than those used in Europe, the response rates for the two continents are strikingly similar. The main differences in a comparison of two samples evaluated in New York and Innsbruck were found in the prevalence of seizures (Innsbruck, 0%; United States, 7.1%) and confusion (Innsbruck, 0%; United States, 14%). Excitement was less prevalent in the U.S. study. The data presented appear to suggest that a lower dose of clozapine may be as effective as a higher dose in the management of treatment-resistant schizophrenic patients and may cause fewer side effects.

Akathisia, Drug-Induced↗
PubMed1994

The use of clozapine in neurologic disorders.

The advent of clozapine has marked a major advance in the treatment of schizophrenia because of its low incidence of extrapyramidal side effects and superior efficacy. Because of a relatively high incidence of agranulocytosis, approved indications for use are limited to treatment-refractory or neuroleptic-intolerant patients with schizophrenia. However, an emerging body of literature suggests that clozapine may be preferable to typical neuroleptics for treating psychosis in certain neurologic disorders. In addition, clozapine may have a place in the treatment of movement disorders that are caused by or are a result of the pharmacologic treatment of some neurologic illnesses. In general, clozapine doses used in these settings are lower than that for treating psychosis in schizophrenia. This article reviews the experience with clozapine in selected neurologic disorders.

Clinical Trials as Topic↗
PubMed1993

Clozapine-induced agranulocytosis. Incidence and risk factors in the United States.

BACKGROUND: Clozapine is an atypical antipsychotic agent that is more effective than standard neuroleptic drugs in the treatment of patients with refractory schizophrenia. Unlike classic neuroleptic agents, clozapine is not associated with the development of acute extrapyramidal symptoms or tardive dyskinesia. The main factor limiting its use is the risk of potentially fatal agranulocytosis, estimated to occur in 1 to 2 percent of treated patients. After clozapine was approved by the Food and Drug Administration, it became available for marketing in the United States in February 1990 only as part of a special surveillance system (the Clozaril Patient Management System, or CPMS), in which a weekly white-cell count was required for the patient to receive a supply of the drug. METHODS: We evaluated the CPMS data for February 1990 through April 1991 by survival analysis to determine the incidence of agranulocytosis and the effects of potential risk factors such as age and sex. Data were available for 11,555 patients who received clozapine during the period after marketing began. RESULTS: Agranulocytosis developed in 73 patients, resulting in death from infectious complications in 2 patients. Episodes of agranulocytosis occurred in 61 patients within three months after they began treatment. The cumulative incidence of this side effect was 0.80 percent (95 percent confidence interval, 0.61 to 0.99) at 1 year and 0.91 percent (95 percent confidence interval, 0.62 to 1.20) at 1 1/2 years. The risk of agranulocytosis increased with age and was higher among women. CONCLUSIONS: The occurrence of agranulocytosis is a substantial hazard of the administration of clozapine, but this hazard can be reduced by monitoring the white-cell count. The increasing risk of agranulocytosis with age and the reduced incidence after the first six months of treatment provide additional guidelines for the prescription and monitoring of clozapine treatment in the future.

Adult↗
PubMed1993

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.

Adult↗
PubMed1993

Brain morphology, dopamine, and eye-tracking abnormalities in first-episode schizophrenia. Prevalence and clinical correlates.

OBJECTIVE: To characterize the pathophysiology of schizophrenia and to identify biologic markers in first-episode patients with no or little prior treatment exposure. DESIGN: Prospective study of an inception cohort. SETTING: Psychiatric division of an academic medical center with a suburban metropolitan catchment area. PATIENTS: 70 patients in their first episode of schizophrenia (77%) or schizoaffective disorder (23%) with no (70%) or limited prior neuroleptic exposure (30%), and 50 healthy volunteer control subjects. ASSESSMENT MEASURES: Demographic and clinical evaluations of natural history and psychopathology; methylphenidate hydrochloride and apomorphine hydrochloride stimulation tests as measures of central nervous system dopamine activity; brain magnetic resonance imaging; eye-tracking examinations. RESULTS: Preliminary analyses demonstrate that pathobiologic features previously identified in heterogeneous and primarily chronically ill patients are also present in subgroups during their first episode. These include psychotogenic response to methylphenidate (59%), abnormal growth hormone (GH) secretion (50%), abnormal brain morphology (31%), and eye-tracking dysfunction (51%). An association of pathobiologic variables with increased symptom severity and earlier age of onset was observed but not statistically significant. The strongest associations among biologic variables were for the following: GH secretion and psychotogenic response to methylphenidate, which may reflect increased dopamine agonist neural activity; decreased GH response to apomorphine and third-ventricle enlargement, which may represent a neuropathologic correlate of anterior pituitary abnormalities; and morphologic abnormalities of the medial temporal lobe and third ventricle were associated with normal eye tracking, suggesting that these pathobiologic features are mediated by distinct processes. CONCLUSIONS: These phenomena appear to be a consequence of the disease rather than the effects of chronicity, drug treatment, or institutionalization. It remains to be determined if these biologic phenomena will remain stable over time or change with disease progression. A companion article examines the clinical significance of these findings.

Adolescent↗
PubMed1993

Neurochemistry and neuroendocrinology of schizophrenia: a selective review.

Neurochemical investigation has played a major role in the search for the cause of schizophrenia. Initial research strategies involved the direct measurement of neurochemical substances in biological fluids. Subsequently, indirect measures of brain biochemistry including pituitary hormones and responses to pharmacologic probes were examined. Recent advances in in vivo functional neuroimaging, biochemical neuropathology, and molecular genetics have extended the scope of clinical neurochemical studies. The historical emphasis on the dopamine neurotransmitter system has subsided in the wake of the demonstrated limitations of the dopamine hypothesis of schizophrenia and increased evidence for the role of other neurotransmitters in the pathophysiology of schizophrenia as well as their interactions with dopamine neural systems. The neurotransmitters that have come under increasing scrutiny include serotonin, norepinephrine, glutamate, and related excitatory amino acids, and the neuropeptides cholecystokinin and neurotensin. In this article, the authors reviewed significant recently published neurochemical and neuroendocrine studies of schizophrenia in the context of previous work and found an extensive but fragmentary body of data which provides neither consistent nor conclusive evidence for any specific etiologic theory. Aspects of the disease and methodological limitations that may account for this as well as future research strategies are discussed.

Humans↗
PubMed1993

Polydipsia and tardive dyskinesia in chronic psychiatric patients--related disorders?

Dopamine supersensitivity, presumably playing a role in tardive dyskinesia, has been implicated in the unexplained polydipsia occurring in chronic psychiatric patients. To investigate this hypothesis, the authors compared laboratory measurements indicating the fluid status of 65 patients before and after the development of tardive dyskinesia. No evidence was found that patients who develop tardive dyskinesia concurrently develop abnormalities in fluid regulation.

Adolescent↗
PubMed1993

Diabetes and development of tardive dyskinesia.

Diabetes mellitus has been identified as a possible risk factor for tardive dyskinesia. The authors examined 160 elderly individuals who were beginning neuroleptic treatment; 24 had diabetes and 136 did not. After 43 weeks of neuroleptic exposure, the cumulative incidence rates of tardive dyskinesia were 54.1% (SE = 5.6%) for the diabetics and 25.6% (SE = 16.1%) for the nondiabetics.

Age Factors↗
PubMed1993

The effect of activation procedures on neuroleptic-induced akathisia.

Two studies have been performed to evaluate the effect of activation tasks on neuroleptic-induced akathisia (NIA). In the first sample (30 patients) we found a consistent increase of symptoms during mental activation while motor activation led to a decrease. In a second study 34 patients with the same diagnosis were evaluated, using slightly different statistical procedures: while the effects of motor activation were corroborated, mental activation did not change NIA. Since mental and motor activation are usually considered to increase tardive dyskinesia and Parkinsonism, these measures might be helpful in differentiating NIA from other antipsychotic-induced movement disorders.

Adult↗
PubMed1993

Understanding the mechanism of action of atypical antipsychotic drugs. A review of compounds in use and development.

The thrust of development of new antipsychotic drugs has been to identify new compounds that have enhanced antipsychotic efficacy and have lesser side-effects than standard neuroleptic compounds. Drug development strategies no longer concentrate on D2 receptor antagonism but aim to produce novel compounds. The following have been pursued: (a) selective dopamine receptor antagonists; (b) serotonin receptor agonists and antagonists (5-HT1a,e'5-HT2,5-HT3) or mixed 5-HT2-D2 receptor antagonist; (c) selective dopamine agonists or partial agonists; and (d) sigma-site and excitatory amino-acid antagonists. Such compounds are at various stages of development. The only drug which has truly distinguished itself as 'atypical' is clozapine. Its mechanism of action is unknown and the search for it, in large part, has been the impetus for development of the compounds listed above.

Antipsychotic Agents↗
PubMed1993

Prediction of outcome in first-episode schizophrenia.

Prompt and efficient treatment of acute psychotic episodes combined with the prevention of relapses will limit the accrued morbidity of schizophrenia. However, the heterogeneity of schizophrenia makes it difficult to determine which individuals are most likely to relapse. There are three major potential biological predictors of schizophrenic relapse: (1) behavioral response to dopamine agonist stimulation, (2) the presence of tardive dyskinesia, and (3) increases in anterior pituitary hormones. Dopamine agonists and dopamine antagonist provocative tests, using a single dose of medication, can be used to predict outcome in stabilized schizophrenics undergoing maintenance drug therapy. These tests are indicators of increased dopamine activity, which potentially indicates a worse outcome. This article discusses behavioral response to psychostimulant tests and pituitary hormone levels, particularly growth hormone and prolactin response to dopamine antagonist stimulation. As predictors of outcome, these measures may be useful, clinically, when selecting neuroleptic maintenance schedules, dosage, or withdrawal strategies.

Antipsychotic Agents↗
PubMed1993

Does clozapine cause tardive dyskinesia?

BACKGROUND: The authors attempted to determine if chronic exposure to clozapine can cause tardive dyskinesia. METHOD: Twenty-eight schizophrenic or schizoaffective patients with no prior history of definite tardive dyskinesia were treated with clozapine for at least 1 year, and their ongoing modified Simpson Dyskinesia Scale ratings were analyzed. These data were then compared with those of another group of similarly diagnosed patients who were treated with a conventional neuroleptic for at least 1 year. RESULTS: Two patients in the clozapine-treated group (both of whom had ratings of questionable tardive dyskinesia at baseline) were later rated by the modified Simpson Dyskinesia Scale as having mild tardive dyskinesia on at least two consecutive ratings 3 months apart. Although there was uncertainty about whether clozapine definitely caused the tardive dyskinesia in those two patients, a survival analysis comparing the clozapine-treated group with the neuroleptic-treated group showed a lower risk of tardive dyskinesia developing in the clozapine-treated group. CONCLUSION: This study was unable to definitively conclude whether clozapine causes tardive dyskinesia. However, if cases do develop, the risk of tardive dyskinesia is likely to be less with clozapine than with typical neuroleptics.

Adult↗
PubMed1993

Schizophrenia and substance abuse.

There is substantial comorbidity between schizophrenia and substance abuse. Although evidence indicates that the course of schizophrenia is complicated by substance abuse, patients perceive benefits from drugs of abuse. Treatment of these patients should be provided in settings with a high degree of psychiatric expertise.

Comorbidity↗