Early neuroleptic response in psychotic men and women: correlation with plasma HVA and MHPG

Plasma homovanillic acid levels in schizophrenic patients: correlation with negative symptoms

The relation between changes in the levels of plasma homovanillic acid (pHVA) and clinical evolution during neuroleptic treatment of schizophrenic patients has not been satisfactorily characterized, as a number of conflicting findings have been reported. Significant correlations have generally been found using the assessment of positive symptoms as an index of clinical outcome. Nevertheless, attempts to correlate pHVA concentrations with negative symptoms have yielded contradictory results. With a view to evaluating if different responses in negative symptoms are associated with distinct pHVA profiles, we examined the levels of pHVA in 46 neuroleptic-free schizophrenic patients and in these patients after neuroleptic treatment. Negative and positive symptoms were also addressed before and after treatment. Our results reveal that at least two classes of negative symptoms exist; the clinical evolution of the first class of negative symptoms parallels that of positive symptoms, and clinical improvement correlates with reduced dopaminergic activity. In contrast, in the second class, reduced dopaminergic activity is associated with a further deterioration of negative symptoms. These findings corroborate the heterogeneity of negative symptoms and may contribute to a better definition of endophenotypes in the schizophrenic syndrome.

A biomodal distribution of plasma HVA/MHPG in the psychoses

In an attempt to estimate dopamine production in psychotic patients, pHVA and pMHPG were assessed from morning blood samples of fasting, neuroleptic-free patients. The (pHVA/pMHPG) ratio was bimodally distributed. The upper mode delineated a cluster of psychotics with excess central dopamine activity. Despite a comparable duration of illness, the high ratio cluster had an earlier age of onset and a more complete subacute response during neuroleptic treatment than did lower ratio patients. Comparisons were made between these clusters and clusters defined by the distribution of pHVA alone. The data suggest a disorder of feedback control of central dopamine metabolism in the high pHVA/pMHPG cluster.

Predicting haloperidol treatment response in chronic schizophrenia

The study attempted to identify pretreatment characteristics of chronic schizophrenic patients that would predict remission in psychosis and amount of clinical improvement after treatment with haloperidol. Thirty-five acutely relapsed schizophrenic patients were entered into a blind 6-week treatment protocol. Pretreatment measures were assessed for prediction of both remission status (dichotomous) and for correlations with change in psychopathology (continuous). Later age of onset and higher plasma homovanillic acid values were significant predictors of remission status (model 1). However, higher cerebrospinal fluid levels of 3-methoxy-4-hydroxyphenylglycol, as well as indices of normal neurodevelopment, predicted larger changes in psychopathology. The results indicate that the definition of drug response determines the predictive variables. Dopaminergic activity seems to relate to the ability to reach remission, while noradrenergic activity relates to symptom intensity and reduction. In addition to catecholamine activity, neurodevelopmental changes determine response to haloperidol.

Effects of raclopride treatment on plasma and CSF HVA: relationships with clinical improvement in male schizophrenics

Thirty-two acutely psychotic, male schizophrenic patients received raclopride, at 2, 6, or 12 mg/day, or haloperidol, 15 mg/day for 4 weeks after randomized, double-blind assignment. Twenty-six patients, including 19 who had been assigned one of the three doses of raclopride, completed the study. Raclopride, particularly at 12 mg/day, increased CSF homovanillic acid (HVA) at 4 weeks, and plasma HVA at 2 days, of treatment. The clinical response to raclopride was significantly correlated with plasma raclopride concentrations and baseline plasma HVA concentrations. Although raclopride is a substituted benzamide with atypical properties in animals, these results suggest that the doses of raclopride required for clinical efficacy and elevation of clinical indices of brain dopamine turnover are similar.

Familial differences between rapid neuroleptic response psychosis and delayed neuroleptic response psychosis

Recent data suggest that latency of neuroleptic response may be used to separate distinct subtypes of psychotic disorders. In this preliminary study we contrast family patterns of illness of rapid neuroleptic response psychotics and delayed neuroleptic response psychotics. The data show that first-degree relatives of delayed neuroleptic response psychotics evidence higher levels of psychiatric disorder than rapid responders: relatives of delayed neuroleptic response psychotics evidenced a morbid risk for schizophrenic-spectrum disorder that was more than twice as high as the morbid risk for such disorders among relatives of rapid neuroleptic response psychotics. Relatives of delayed neuroleptic responders that received a diagnosis of schizophrenia, schizoaffective, or schizophreniform disorder evidenced significantly more residual impairment than schizophrenic-spectrum relatives of rapid neuroleptic responders. These preliminary data indicate the possibility that latency of therapeutic response to neuroleptic medication may be used to discriminate two familially distinct psychotic disorders and they suggest that delayed neuroleptic response may characterize a familially transmitted poor-outcome disease.

The biochemical basis of relapse and drug response in schizophrenia: review and hypothesis

This review of the literature suggests that antipsychotic drug response is determined by dopamine (DA) turnover and norepinephrine (NE) activity prior to treatment. The data suggest that NE modulates the DA system. Drug-free psychotic patients with relatively increased DA and NE activity, including release, are more likely to be treatment responsive, while patients who show evidence of enhanced DA and NE activity during treatment with antipsychotic drugs are likely to relapse soon after neuroleptic withdrawal. Basal release of DA and NE is decreased and associated with residual positive and negative symptoms. Improvement during neuroleptic treatment is associated with decreases in DA and NE phasic or stimulus induced release. The variable response to antipsychotic drugs is most likely to be a result of dysregulated DA and NE release, i.e. under state-dependent control, rather than evidence of a heterogeneous aetiology. Because catecholamines regulate gain, signal-to-noise ratio and gating in the brain, this model allows for environmental factors to interact with biochemical state and drug treatment. The author proposes that impaired homeostasis of NE and DA in schizophrenia causes instability in NE and DA neuronal firing and release, presumably related to mechanisms down-stream from the receptors, such as G proteins. This instability of catecholamine release may explain the observed variability in clinical states and drug response in schizophrenia.

Dopamine and norepinephrine activity in schizophrenia. An integrative perspective

The dopamine (DA) hypothesis of schizophrenia stated that increased DA activity is the primary cause of schizophrenia. Recently, even though increased DA activity is in fact involved in psychotic symptoms and antipsychotic drug response, it has become clear that decreased DA activity is present in remitted and chronic states and may relate to deficit symptoms and cortical lesions. In addition, the norepinephrine (NE) system seems to be involved in symptomatology, antipsychotic drug response, course, and outcome in schizophrenia. This review supports the hypothesis that a disturbance in DA and NE activity regulates schizophrenic behavior. A plethora of DA- and NE-related findings in schizophrenic patients are reviewed in relationship to each other according to basic science data and to presently entertained hypotheses, with emphasis on a neural developmental disturbance interacting with a genetic predisposition shaped by environmental factors.

On the selection of mice for haloperidol response and non-response

Mice have been selected over eight generations for response and non-response to haloperidol-induced catalepsy. The selection has been asymmetric, with significantly faster divergence for the haloperidol non-responder (HNR) line as compared to the haloperidol responder (HR) line. After six generations of selection, the ED50 in the HNR line was 4.3 mg/kg and 0.4 mg/kg in the HR line. Spiroperidol, fluphenazine and trifluoperazine showed a 10-fold or greater discrimination between lines. Raclopride, a specific dopamine D2 antagonist, showed a 7-fold discrimination between lines. Chlorpromazine, thiothixene, (+) butaclamol and cis-flupenthixol showed a 3-4-fold discrimination between lines. The specific D1 antagonist, SCH 23390, was the most potent cataleptogenic agent tested (ED50 = 0.1 mg/kg) and did not discriminate between the lines. The HR and HNR lines did not differ in post-synaptic D2 receptor affinity or density as assessed by quantitative receptor autoradiography and membrane binding assays. However, A-9 somatodendritic receptor density was 80% higher in the HNR line as compared to the HR line.

Sensory physiology and catecholamines in schizophrenia and mania

Hypersensitivity to sensory stimulation is a prominent characteristic of both schizophrenia and mania. Neurophysiological recordings suggest a common deficit in a central neuronal sensory gating mechanism which regulates sensitivity to repeated auditory stimuli. Dopamine and norepinephrine are hypothesized to have major roles in these illnesses, but their role in aberrant sensory processing has not yet been proved. Presumptive evidence for effects of catecholamines on sensory processing comes from psychophysiological studies of normal subjects challenged with stimulants who show decreased sensory gating, and studies of psychotic patients treated with neuroleptics who show improved function. Studies of similar phenomena in animals show comparable effects of catecholamines on sensory processing, both behaviorally and at the single neuron level. In this study, gating of auditory evoked potentials (EPs) during treatment of both illnesses was compared with plasma dopamine and norepinephrine metabolites. Comparisons of medicated and unmedicated states showed that schizophrenic patients have a fixed deficit in sensory gating, which is a familial trait, unchanged by medication. During acute illness, they have an additional transient hypersensitivity to stimuli, manifested as smaller EPs, which seems to be mediated by dopamine. Manic patients have only the deficit in sensory gating, which is transient and seems to be mediated by norepinephrine. Thus, similar neurophysiological deficits in the two psychoses are associated with different biochemical abnormalities, which may explain similarities in acute symptoms and differences in other aspects of the illnesses, such as their response to treatment.

Relationships between clinical effects and monoamine metabolites and amino acids in sulpiride-treated schizophrenic patients

Twenty-four acutely ill schizophrenic patients (DSM-III-R), 18-42 years old, were treated for 6 weeks with sulpiride. Sulpiride was administered in three different daily dosages (400, 800 or 1200 mg) according to a double dummy blind randomized administration schedule. The psychopathology of the patients was rated by the Comprehensive Psychopathological Rating Scale (CPRS) and the Nurse's Observation Scale for Inpatient Evaluation (NOSIE). The monoamine metabolites homovanillic acid (HVA), 5-hydroxy-indoleacetic acid (5-HIAA), 4-hydroxy-3-methoxy-phenylglycol (HMPG) and the amino acids tyrosine, tryptophan, glutamate and glutamine were measured in serum before and once a week during sulpiride treatment. There were no significant correlations between the CPRS or the NOSIE morbidity scores and the biochemical measures before drug treatment. HVA levels were not correlated to rating scores during treatment, but after 6 weeks HVA had decreased significantly in the patients with a good response but not in the patients with a poor response. A negative relationship between 5-HIAA levels and depressive and negative symptoms was found. Non-responders according to the subscale for depression had low 5-HIAA levels throughout the treatment. An increase of tryptophan was correlated to improvement in the early part of treatment. High levels of glutamate or glutamine were found in non-responders before treatment. During treatment an increase of the glutamate level was correlated to improvement. Low levels of glutamine were related to improvement according to global and NOSIE (total) rating scores. Peripheral biochemical measures may be a valuable tool in the study of pathophysiological mechanisms and treatment effects in patients with schizophrenia.

Double blind comparative study of remoxipride and haloperidol in acute schizophrenic patients

In the present 6-week double-blind, randomised, multicentre study, the atypical neuroleptic remoxipride was compared to haloperidol in acute schizophrenic patients (DSM-III). Seventy-one patients entered the study, 36 in the remoxipride group and 35 in the haloperidol group. There were ten early withdrawals, four in the remoxipride group and six patients in the haloperidol group. The Present State Examination (PSE) profile revealed a similar reduction in the symptom clusters of psychosis in both treatment groups. Forty-seven per cent of the patients in the remoxipride group and 34% of the patients in the haloperidol group showed clinically relevant improvement (reduction of BPRS total score greater than or equal to 50%). All extrapyramidal symptoms except "glabella tap" occurred significantly less frequently in the remoxipride group as compared to the haloperidol group. Substantially lower incidences of EPS were found by active questioning in the remoxipride group compared to the haloperidol group. In addition, considerably lower incidences were observed in the remoxipride group with respect to drowsiness/somnolence, tiredness/fatigue and concentrating difficulty. At the end of treatment 66% of the patients in the haloperidol group and 22% in the remoxipride group were using anticholinergics. No consistent changes were found in the mean plasma HVA level in either treatment group. In responders (reduction of BPRS total score greater than or equal to 50%) lower baseline HVA levels were observed in both treatment groups. This study indicates that the newly developed neuroleptic remoxipride is an effective antipsychotic compound, which is clinically safe and well tolerated. In particular, few EPS were induced by remoxipride, as compared to haloperidol.

Drug therapy in schizophrenia--variability of outcome and prediction of response

In spite of the proven benefits of neuroleptics in reducing acute psychotic symptoms and in preventing relapse in schizophrenic patients, not all schizophrenics benefit equally from neuroleptic therapy. Predictors of response include: demographics, clinical characteristics, neurologic soft signs, neurocognitive functioning, morphologic brain changes, drug blood levels, indices of blockade of the dopamine receptors, subjective response to medications as well as early symptomatic improvement. Methodological difficulties in outcome research in drug therapy are reviewed. No single factor has been identified as a reliable predictor of drug response, and it is unlikely that such a single predictor will prove useful in a heterogeneous illness such as schizophrenia. This paper reviews the factors, which have been suggested as useful in developing better understanding of variability of drug response among schizophrenics.

Pharmacodynamics and pharmacokinetics of haloperidol and reduced haloperidol in schizophrenic patients

Twelve male chronic schizophrenic inpatients, neuroleptic-free for at least 4 weeks, were given an oral test dose of 10 mg haloperidol (HAL) and reduced HAL (RHAL) in a random order, with a 2-week interval. Two weeks after the last test dose, the patients were given HAL, 5 mg orally twice daily for 7 days. Blood samples were drawn at baseline and between 0.5 and 24 hr after the test doses, and during HAL treatment as well. Plasma drug concentrations and homovanillic acid (HVA) levels were measured with high-performance liquid chromatography using electrochemical detection. HAL, but not RHAL, produced increments in plasma HVA (pHVA) levels at 24 hr after a test dose. pHVA levels remained higher than baseline during HAL treatment. Detectable interconversion between HAL and RHAL was observed in eight patients. The capacity of the reductive drug-metabolizing enzyme system, however, was greater than that of the oxidative processes. The plasma RHAL:HAL ratios on days 6 and 7 were higher than and positively correlated with those at Tmax after a single dose of HAL and were negatively correlated with the HAL:RHAL ratios at Tmax after a single dose of RHAL. Thus, both reductive and oxidative drug-metabolizing systems probably contribute to individual differences in plasma RHAL:HAL ratios in HAL-treated schizophrenic patients.

Biogenic amines and their metabolites in body fluids of normal, psychiatric and neurological subjects

The biogenic monoamines and their metabolites have been isolated, identified and quantified in human body fluids over the past forty years using a wide variety of chromatographic separation and detection techniques. This review summarizes the results of those studies on normal, psychiatric and neurological subjects. Tables of normal values and the methods used to obtain them should prove to be useful as a reference source for benchmark amine and metabolite concentrations and for successful analytical procedures for their chromatographic separation, detection and quantification. Summaries of the often contradictory results of the application of these methods to psychiatric and neurological problems are presented and may assist in the assessment of the validity of the results of experiments in this field. Finally, the individual, environmental and the methodological factors affecting the concentrations of the amines and their metabolites are discussed.

Plasma catecholamine metabolites and treatment response at neuroleptic steady state

Using either haloperidol or perphenazine in a fixed-dose protocol, plasma free homovanillic acid (HVA) and methoxyhydroxyphenethylglycol (MHPG) were decreased in 37 nonorganic psychotic inpatients at neuroleptic steady state (7-9 days) in comparison with pretreatment values. The data indicate that the magnitude of the decline in HVA and MHPG was associated with treatment response and not with neuroleptic plasma levels.

Plasma homovanillic acid levels and subtyping of schizophrenia

Plasma levels of homovanillic acid (HVA), a major metabolite of dopamine, were measured in a group of 24 schizophrenic inpatients before and during 6 weeks of haloperidol (HAL) treatment. Steady-state plasma HAL levels were measured in parallel with plasma HVA. Differential plasma HVA responses to HAL treatment were found between good and poor outcome patients. The two groups did not differ significantly in plasma HAL levels. Two hypothetical subtypes of schizophrenia are proposed.

Reproducibility of the measurement of plasma noradrenergic and dopaminergic metabolites in normal subjects

The object of this study was to determine the reproducibility of the measurement of plasma catecholamine metabolites in normal control subjects and to assess the influence of factors such as time of day, diet, activity, blood pressure, and mood on the variance of these measures. Plasma free homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol (MHPG), and vanillylmandelic acid (VMA) were simultaneously measured by high performance liquid chromatography with electrochemical detection. Samples were collected from 15 doctors and nurses at 8 a.m. and at noon on 2 separate days. After the fasting 8 a.m. sample, the subjects ate a regular hospital breakfast. Activity in their usual tasks on an inpatient psychiatric unit was monitored electronically by an activity meter. Levels of each metabolite were not significantly different between days at the respective assay times and were highly correlated for individuals. MHPG showed a significant increase from morning to noon, while HVA showed a significant decrease. Activity, dietary intake of tyrosine and tyramine, blood pressure, pulse, scores on the Profile of Mood States, age, and sex were not related to plasma levels. The results demonstrate that measures of dopamine and norepinephrine metabolites have significant reliability in normal subjects in a setting used for research studies with psychiatric patients.