Plasma free homovanillic acid (HVA) as a predictor of clinical response in acute psychosis

Candidate metabolic biomarkers for schizophrenia in CNS and periphery: Do any possible associations exist?

Due to the limitations of analytical techniques and the complicity of schizophrenia, nowadays it is still a challenge to diagnose and stratify schizophrenia patients accurately. Many attempts have been made to identify and validate available biomarkers for schizophrenia from CSF and/or peripheral blood in clinical studies with consideration to disease stages, antipsychotic effects and even gender differences. However, conflicting results handicap the validation and application of biomarkers for schizophrenia. In view of availability and feasibility, peripheral biomarkers have superior advantages over biomarkers in CNS. Meanwhile, schizophrenia is considered to be a devastating neuropsychiatric disease mainly taking place in CNS featured by widespread defects in multiple metabolic pathways whose dynamic interactions, until recently, have been difficult to difficult to investigate. Evidence for these alterations has been collected piecemeal, limiting the potential to inform our understanding of the interactions among relevant biochemical pathways. Taken these points together, it will be interesting to investigate possible associations of biomarkers between CNS and periphery. Numerous studies have suggested putative correlations within peripheral and CNS systems especially for dopaminergic and glutamatergic metabolic biomarkers. In addition, it has been demonstrated that blood concentrations of BDNF protein can also reflect its changes in the nervous system. In turn, BDNF also interacts with glutamatergic, dopaminergic and serotonergic systems. Therefore, this review will summarize metabolic biomarkers identified both in the CNS (brain tissues and CSF) and peripheral blood. Further, more attentions will be paid to discussing possible physical and functional associations between CNS and periphery, especially with respect to BDNF.

Antidopaminergic medication in healthy subjects provokes subjective and objective mental impairments tightly correlated with perturbation of biogenic monoamine metabolism and prolactin secretion

OBJECTIVES

Off-label prescription of antipsychotics to patients without psychotic symptoms has become a routine matter for many psychiatrists and also some general practitioners. Nonetheless, little is known about the possibly detrimental effects of antidopaminergic medications on general psychopathology, subjective mental state, or a possible association with physiological parameters in nonpsychotic individuals.

METHODS

In this randomized, single-blinded study, groups of healthy volunteers (n=18) received low doses of reserpine, aripiprazole, haloperidol, or placebo on 7 successive days. Relevant physiological parameters (plasma prolactin, concentrations of catecholamine metabolites in plasma, and 24-hour urine) and each subject's mental state (Positive and Negative Syndrome Scale, Hamilton Rating Scale for Depression, visual analogue scale, Beck Depression Inventory II) were assessed at the start and end of the trial.

RESULTS

Of the three active treatments, only reserpine caused a significant increase in some plasma- and urine-catecholamine metabolites, but all three medications evoked objective and subjective changes in general psychopathology scores, which correlated with individual increases in plasma homovanillic acid concentrations. Both objective and subjective impairments were significantly more pronounced in the subgroup with greatest increase of plasma prolactin. Subjects experiencing the most pronounced side effects under haloperidol, which compelled them to drop out, showed significantly higher prolactin concentration increases than those who tolerated haloperidol well.

CONCLUSION

We found consistent associations between altered markers of dopamine transmission and several objective and subjective mental impairments in healthy volunteers after 1 week's treatment with antidopaminergic medications. These findings should draw attention to a more intensive risk-benefit evaluation in cases of off-label prescription of antipsychotic medications.

Relationships between serum brain-derived neurotrophic factor, plasma catecholamine metabolites, cytokines, cognitive function and clinical symptoms in Japanese patients with chronic schizophrenia treated with atypical antipsychotic monotherapy

OBJECTIVES

Catecholamines, brain-derived neurotrophic factor (BDNF) and cytokines may be involved in the pathophysiology of schizophrenia. The aim of this study was to examine the associations between serum BDNF levels, plasma catecholamine metablolites, cytokines and the cognitive functions of patients with schizophrenia treated with atypical antipsychotic monotherapy.

METHODS

One hundred and forty-six patients with schizophrenia and 51 age- and sex-matched healthy controls were examined for peripheral biological markers and neurocognitive test.

RESULTS

There were positive correlations between serum BDNF levels and scores for verbal memory and attention and processing speed as well as between serum BDNF levels and negative symptoms. Furthermore, there was a negative correlation between the plasma homovanillic acid (HVA) level and motor function and a positive correlation between the plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) level and attention and processing speed. There were no significant correlations between interleukin-6 or tumour necrosis factor alpha and cognitive function. Moreover, there were no significant correlations between the plasma levels of HVA, MHPG, cytokines and clinical symptoms.

CONCLUSIONS

Serum BDNF levels are positively related to the impairment of verbal memory and attention, plasma HVA levels are positively related to motor function, and plasma MHPG levels are positively related to attention in patients with schizophrenia.

Blood Biomarkers Predict the Cognitive Effects of Aripiprazole in Patients with Acute Schizophrenia

Aripiprazole has been reported to exert variable effects on cognitive function in patients with schizophrenia. Therefore, in the present study, we evaluated biological markers, clinical data, and psychiatric symptoms in order to identify factors that influence cognitive function in patients with schizophrenia undergoing aripiprazole treatment. We evaluated cognitive function in 51 patients with schizophrenia using Brief Assessment of Cognition in Schizophrenia (BACS), as well as background information, psychiatric symptoms, plasma catecholamine metabolites-homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol (MHPG)-, and serum brain-derived neurotrophic factor (BDNF). Multivariate analyses were performed in order to identify factors independently associated with cognitive function. Brain-derived neurotrophic factor levels, number of hospitalizations, and MHPG levels were associated with verbal memory and learning. Total hospitalization period and MHPG levels were associated with working memory. Age at first hospitalization and education were associated with motor speed. The number of hospital admissions, Positive and Negative Syndrome Scale negative subscale scores (PANSS-N), MHPG levels, BDNF levels, and Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS) scores were associated with verbal fluency. Homovanillic acid and MHPG levels, duration of illness, and PANSS-N scores were associated with attention and processing speed. Brain-derived neurotrophic factor and MHPG levels were associated with executive function. These results suggest that treatment of psychiatric symptoms and cognitive dysfunction may be improved in patients treated with aripiprazole by controlling for these contributing factors.

Yokukansan improves behavioral and psychological symptoms of dementia by suppressing dopaminergic function

Although three drugs, risperidone, yokukansan, and fluvoxamine, have shown equal efficacy in treating behavioral and psychological symptoms of dementia (BPSD) in our previous study, their mechanisms of action are different from one another. Monoamines have attracted attention for their key roles in mediating several behavioral symptoms or psychological symptoms through synaptic signaling. We aimed to clarify the monoamines changed by treatment with each drug in patients with BPSD. The main purpose of this study was to determine whether plasma levels of catecholamine metabolites are correlated with pharmacological treatments. This was an 8-week, rater-blinded, randomized, flexible-dose, triple-group trial. In total, 90 subjects were recruited and subsequently three different drugs were allocated to 82 inpatients with BPSD. We examined BPSD data from patients who completed 8 weeks of treatment. Eventually, we analyzed 42 patients (yokukansan: 17; risperidone: 9; fluvoxamine: 16). Homovanillic acid, a metabolite of dopamine, and 3-methoxy-4-hydroxyphenylglycol, a metabolite of noradrenaline, in their plasma were analyzed by high-performance liquid chromatography with electrochemical detection. All three drugs showed equal significant efficacy between baseline and study endpoint. By contrast, biomarkers showed mutually different changes. Patients in the yokukansan group had significantly decreased plasma homovanillic acid levels from baseline. Conversely, patients in the risperidone and fluvoxamine groups exhibited no significant changes in plasma homovanillic acid levels from baseline. Yokukansan contains geissoschizine methyl ether, which is known to have a partial agonist effect on dopamine D2 receptors. An improvement in BPSD condition with the intake of yokukansan is suggested to occur through a suppressed dopaminergic function, which is similar to the effect of aripiprazole.

Associations between five-factor model of the Positive and Negative Syndrome Scale and plasma levels of monoamine metabolite in patients with schizophrenia

The five-factor model of the Positive and Negative Syndrome Scale (PANSS) for schizophrenia symptoms is the most common multiple-factor model used in analyses; its use may improve evaluation of symptoms in schizophrenia patients. Plasma monoamine metabolite levels are possible indicators of clinical symptoms or response to antipsychotics in schizophrenia. We investigated the association between five-factor model components and plasma monoamine metabolites levels to explore the model's biological basis. Plasma levels of homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA) were measured using high-performance liquid chromatography in 65 Japanese patients with schizophrenia. Significant negative correlation between plasma 5-HIAA levels and the depression/anxiety component was found. Furthermore, significant positive correlation was found between plasma MHPG levels and the excitement component. Plasma HVA levels were not correlated with any five-factor model component. These results suggest that the five-factor model of the PANSS may have a biological basis, and may be useful for elucidating the psychopathology of schizophrenia. Assessment using the five-factor model may enable understanding of monoaminergic dysfunction, possibly allowing more appropriate medication selection. Further studies of a larger number of first-episode schizophrenia patients are needed to confirm and extend these results.

Review: The biological basis of antipsychotic response in schizophrenia

Schizophrenia is a severe mental illness affecting approximately 1% of the population worldwide. Antipsychotic drugs are effective in symptom control in up to two-thirds of patients, but in at least one-third of patients the response is poor. The reason for this is not clear, but one possibility is that good and poor responders have different neurochemical pathologies, and may therefore benefit from different treatment approaches. In this selective review we summarise research findings investigating the biological differences between patients with schizophrenia who show a good or a poor response to treatment with antipsychotic drugs.

Plasma homovanillic acid differences in clinical subgroups of first episode schizophrenic patients

This study evaluates the relationship between plasma homovanillic acid (pHVA) levels, which have been used to study the role of central dopamine in schizophrenia, and the positive/negative syndrome in first episode schizophrenic patients before and after antipsychotic treatment. Forty neuroleptic-naive first episode schizophrenic patients were monitored at baseline and on days 7, 14 and 28. Clinical status was evaluated with the Scale for the Assessment of Positive Symptoms (SAPS), the Scale for the Assessment of Negative Symptoms (SANS), and the Brief Psychotic Rating Scale. Plasma HVA levels were also measured. Patients were divided into predominantly positive or negative syndrome groups by subtracting SAPS from SANS scores, at baseline. A healthy control group was also enrolled. Schizophrenic patients as a group had significantly higher pHVA levels than controls at baseline (20.50+/-11.85 vs. 13.04+/-7.22 ng/ml). Moreover, 12 predominantly negative syndrome patients had similar mean baseline pHVA levels (21.30+/-12.36 ng/ml) to those of 28 predominantly positive syndrome patients (19.40+/-11.33 ng/ml). During follow-up, there was a different evolution of pHVA levels in the predominantly positive syndrome group than in the predominantly negative syndrome group, with a significantly greater global reduction of pHVA levels in the former. Although both groups showed clinical improvement following 4 weeks of treatment with risperidone, pHVA levels at endpoint were lower (13.29+/-5.91 ng/ml) than at baseline in patients in the predominantly positive syndrome group, while among those in the predominantly negative syndrome group there was no difference in pHVA levels before and after treatment (21.02+/-13.06 ng/ml). The different pHVA level profiles observed in predominantly positive and negative syndrome first episode patients after 4 weeks of treatment with risperidone suggest that each syndrome may have a different underlying neurobiology.

The biochemical womb of schizophrenia: A review

The conclusive identification of specific etiological factors or pathogenic processes in the illness of schizophrenia has remained elusive despite great technological progress. The convergence of state-of-art scientific studies in molecular genetics, molecular neuropathophysiology, in vivo brain imaging and psychopharmacology, however, indicates that we may be coming much closer to understanding the genesis of schizophrenia. In near future, the diagnosis and assessment of schizophrenia using biochemical markers may become a "dream come true" for the medical community as well as for the general population. An understanding of the biochemistry/ visa vis pathophysiology of schizophrenia is essential to the discovery of preventive measures and therapeutic intervention.

Inter- and intra-individual variability in the levels of plasma homovanillic acid in schizophrenic patients

BACKGROUND

Changes in the levels of homovanillic acid in blood plasma (pHVA) may reflect changes which occur in the brain. In healthy individuals, this concentration of pHVA is stable over time.

METHODS

Over the course of one month, we studied 98 acute schizophrenic patients who had not been taking any medication but were administered neuroleptics upon hospital admission, together with 23 chronic schizophrenic patients on long-term treatment from whom medication was withdrawn. Blood samples were taken at regular intervals from each individual and the concentration of plasma homovanillic acid was measured.

RESULTS

We found relative stable values of pHVA with an intraclass correlation coefficient of 0.363 in acute patients and 0.638 (p<0.0001) in chronic patients, although no differences were found in mean values (13.79 and 14.18 microg/L, respectively) or in the variation range (7.20 to 26.7 microg/L and 6.96 to 29.96 microg/L respectively). The index of individuality was calculated to be 1.36 in acute patients and 0.74 in chronic patients.

CONCLUSIONS

Despite the wide range of values in the concentration of pHVA and the presence of pharmacological stimuli, we found a certain reproducibility in the levels of this dopamine metabolite. These findings are consistent with the idea that the dopaminergic activity is characterized by a constitutive value which would be under genetic control. The higher stability observed in chronic patients may reflect a weaker, age-related dopaminergic plasticity; conversely, it may indicate that a lack of plasticity in response to a pharmacological stimulus may be an indicator of poorer prognosis.

Some biological correlates of drug resistance in schizophrenia: a multidimensional approach

Drug resistance in schizophrenic disorders treated with an antipsychotic medication is highly problematic, lacking sound criteria to define it, and to discriminate between drug response and clinical remission. This article reviews some neurochemical, psychoimmunological, pharmacogenetic and neuromorphological patterns which can affect drug response and determine drug-resistance phenomena in schizophrenia. Several neurochemical abnormalities have been reported to be relevant for the pathogenesis of schizophrenic disorders and have been related to clinical symptoms as well as to the quality of response to antipsychotics: most of the findings come from studies on DA and 5HT brain metabolism, but more recently other non-dopaminergic pathways have been implicated (e.g., glutamatergic ones). Literature data suggest that schizophrenia may be associated with significant alterations of T-cell functions, showing the activation of the inflammatory response system (IRS), particularly in treatment-resistant schizophrenia, and differential effects on IRS have been reported for conventional and atypical antipsychotics. Furthermore molecular genetic approaches provide a novel method of dissecting the heterogeneity of psychotropic drug response, providing the means of determining the molecular substrates of drug efficacy and drug-induced adverse events. On the other hand, functional neuroimaging techniques, including single photon emission computed tomography (SPECT), positron emission tomography (PET) and functional magnetic resonance imaging (FMRI), providing an in vivo assessment of the expression and function of neuroreceptors, transporters and enzymes, seem to be particularly promising for a better understanding of 'real' drug resistance. Finally, a multidimensional approach taking into account all these variables in the future would likely be the more valuable strategy to optimise response, reducing relapses or resistant clinical situations.

Plasma levels of homovanillic acid and the response to risperidone in first episode untreated acute schizophrenia

We have previously reported that risperidone might improve negative symptoms in schizophrenia by influencing noradrenergic neurons. In the present study, we focused on the clinical efficacy and mechanisms of risperidone towards positive symptoms in the acute phase of schizophrenia. Thirty-four patients meeting DSM-IV criteria for schizophrenia and treated with risperidone alone were evaluated regarding their clinical improvement using the Positive and Negative Syndrome Scale (PANSS) before and 2 weeks after risperidone administration, and blood samples were also drawn at the same times. Plasma concentrations of homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol were analysed by high-performance liquid chromatography with electrochemical detection. Plasma HVA levels in the responders to the risperidone treatment (more than 50% improvement in scores of positive symptoms in PANSS) were higher than those of non-responders before risperidone administration. Furthermore, there was a negative trend between changes in plasma HVA levels and improvement of total scores for positive symptoms in PANSS. These results suggest that higher levels of plasma HVA before risperidone administration might be a predictor of a good response to risperidone treatment, and the influence of risperidone on dopaminergic activity might be associated with its efficacy in treating symptoms of schizophrenia in the acute phase.

Neuropsychological impairments in neuroleptic-responder vs. -nonresponder schizophrenic patients and healthy volunteers

To determine whether two groups of schizophrenic patients representing the two extremes of the neuroleptic response-spectrum (consistent responders vs. consistent nonresponders) differ with respect to their neuropsychological profile. Neuroleptic-responder (R; n=36) and -nonresponder (NR; n=39) schizophrenic patients were recruited according to a priori defined criteria of responsiveness to typical neuroleptics. Seven neuropsychological domains were assessed and compared between groups: attention-vigilance, abstraction-flexibility, spatial organization, visual-motor processing, visual memory, verbal abilities, and verbal memory and learning. All measures were standardized using the scores of 36 healthy volunteers. NR schizophrenic patients performed worse in all neuropsychological domains compared to normal controls and R schizophrenic patients. However, only performances on visual memory, verbal abilities, and verbal memory and learning were significantly poorer in NR compared to R patients. Only the latter domain significantly differentiated NR patients from the other two groups. R patients performed at an intermediate level in all domains. This report of differences in neuropsychological profile between neuroleptic-responder and -nonresponder schizophrenic patients adds to the growing evidence supporting the value of distinguishing schizophrenic patients on the basis of their therapeutic response to neuroleptics.

Cardiovascular autonomic reactivity in schizophrenics under neuroleptic treatment: A potential predictor of short-term outcome?

In schizophrenics cardiovascular autonomic reactivity (CAR) can be used as an indicator of autonomic arousal. Using a standardized autonomic test battery (modified according to Ewing and Clarke) we prospectively compared the CAR between 46 actually ill schizophrenics (diagnosis according to DSM-III-R) treated with either haloperidol (n = 26) or clozapine (n = 20) and 30 well-matched healthy volunteers. Multivariate analysis demonstrated a significant effect of neuroleptic medication (haloperidol vs. clozapine) on heart rate and diastolic blood pressure under resting conditions as well as on the heart rate variance (30:15 ratio, deep-breathing, Valsalva) and blood pressure tests (sustained handgrip, Schellong). In addition a positive treatment response (using predefined outcome criteria of the Brief Psychiatric Rating Scale) was independently associated with lower resting heart rates and less impaired 30:15 ratios under neuroleptic medication. Our data indicate that clozapine treatment was associated with a substantial impairment of CAR, which can be explained by the drug's anticholinergic properties in combination with an increase in norepinephrine outflow. The greater heart rate variability in responders might be due to an early neuroleptic-induced decrease of sympathetic activity in the autonomic nervous system, which may precede clinical improvement. Our findings are discussed in relation to neuroleptic-induced changes in plasma catecholamine levels suggested to be useful biological markers in predicting treatment outcome.

Neurochemical variables in schizophrenic patients during switching from neuroleptics to clozapine

1. The study aimed to search for the effect of clozapine on the levels of the main metabolites of dopamine homovanillic acid (HVA), serotonin 5-hydroxyindoleacetic acid (5-HIAA) and norepinephrine 3-methoxy-4-hydroxyphenylglycol (MHPG) in urine as well as on plasma levels of HVA, 5-HIAA, prolactin (PRL) and cortisol. 2. Seventeen male patients diagnosed as suffering from DSM-IIIR schizophrenia completed the study. 3. The patients were switched from classical antipsychotics to clozapine. After six weeks treatment with clozapine the severity of psychopathology (total BPRS score) decreased significantly (p = 0.00004). pHVA and -5-HIAA did not change significantly. uMHPG increased significantly (p = 0.017). Both PRL and cortisol levels decreased significantly (p = 0.0002, p = 0.032 respectively). Patients with high HVA levels in both plasma and urine at baseline had a lower BPRS score at the end of treatment period (p = 0.0001, p = 0.049 respectively).

Pretreatment plasma homovanillic acid in schizophrenia and schizoaffective disorder: the influence of demographic variables and the inpatient drug-free period

BACKGROUND

The relationship between plasma homovanillic acid (pHVA) and schizophrenic symptoms has not been conclusively determined. We reexamine pHVA levels in a new sample of patients with emphasis on demographic variables and the drug-free period.

METHODS

Plasma HVA levels were studied in 54 schizophrenic and schizoaffective-disordered, drug-free inpatients suffering from a psychotic exacerbation.

RESULTS

A significant correlation was observed between pHVA levels and the number of inpatient drug-free days in the total sample, as well as the schizophrenic patient subsample. Further, pHVA was significantly and positively correlated with the duration of illness in the schizophrenic patient subsample. Plasma HVA correlations with behavior, as measured by Brief Psychiatric Rating Scale factors (anxiety/depression and hostility/suspiciousness), emerged only when considering schizophrenic patients drug-free for more than 2 weeks. No correlation was found between pHVA and the age of illness onset or the duration of the delay of treatment of the first psychotic episode.

CONCLUSIONS

The effects of antipsychotic withdrawal on levels of pHVA in clinical populations may have to be examined and controlled for in future studies attempting to study the relationship between this metabolite and behavior in acutely ill, drug-free schizophrenic patients.

Plasma homovanillic acid and the dopamine transporter during cocaine withdrawal

BACKGROUND

Plasma homovanillic acid (HVA) has been used as a measure of central dopaminergic activity but the validity of this method continues to be investigated. We used single photon emission tomography (SPECT) assessment of the dopamine (DA) transporter for comparison with plasma HVA in subjects at varying stages of abstinence from cocaine.

METHODS

Nineteen subjects were studied in two separate treatment sites. Plasma HVA and methoxyhydroxyphenethyleneglycol (MHPG) were measured by gas chromatography-mass spectroscopy (GC-MS). The DA transporter was quantified using the SPECT ligand [123I]B-CIT.

RESULTS

At 2 weeks of abstinence and beyond there was an increasing positive correlation between plasma HVA and the SPECT measurement of the DA transporter (V3").

CONCLUSIONS

Plasma HVA may be more likely to reflect DA transporter density in the striatum when there is not a major drug-related change in the DA system.

Pretreatment plasma HVA predicts neuroleptic response in manic psychosis

Elevated pretreatment plasma free homovanillic acid (HVA) predicted acute response to neuroleptic treatment in patients with manic psychosis. These findings suggest that plasma HVA may be a useful predictor of a successful short-term response in manic as well as schizophrenic psychoses, and that elevated pre-synaptic dopaminergic release may play a role in more than one group of psychotic disorders.

Association of plasma homovanillic acid with behavioral symptoms in patients diagnosed with dementia: a preliminary report

Neuroleptic treatment of psychotic symptoms or agitated behavior in elderly patients diagnosed with dementia is associated with reduced efficacy and increased rates of neuroleptic-induced parkinsonism in comparison to younger patients with schizophrenia. We report the first study to examine the relationship between an in vivo measure of dopaminergic function, plasma homovanillic acid (pHVA), and ratings of psychosis, agitation, and parkinsonism before and after neuroleptic treatment in dementia patients. Pretreatment pHVA was significantly correlated with parkinsonian rigidity, with a trend observed with agitation and hostility. Though mean pHVA did not change during perphenazine treatment, intraindividual change in pHVA at day 15 was correlated with improvement in hostility, with a similar trend for improvement in agitation. These preliminary findings are consistent with reports associating dopaminergic function with agitated, but not psychotic, symptoms in patients diagnosed with dementia, and with a reduced responsivity of dopaminergic systems to neuroleptic treatment in these patients.

New dopaminergic and non-dopaminergic theories in schizophrenia and their therapeutic impact

The dopamine (DA) hypothesis of schizophrenia, postulating that schizophrenia is characterized by increased dopamine function, has been the most influential theory on the pathogenesis of schizophrenia. It has recently been revised based on the appreciation that the core symptoms of schizophrenia may not be the positive (psychotic) symptoms, but rather the negative symptoms and the cognitive deficits found in schizophrenic patients. This revision has prompted the hypothesis that schizophrenia is characterized by both decreased prefrontal dopamine activity (causing deficit symptoms) and increased dopamine activity in mesolimbic dopamine neurons (causing positive symptoms). Notwithstanding this revision of a role for dopamine in schizophrenia, it has become increasingly evident that dysfunction of other monoaminergic systems may be as important in contributing to the pathophysiology of schizophrenia. Specifically, the putative role of serotonin (5-hydroxytryptamine, 5-HT) in schizophrenia is gaining considerable attention. Several observations, such as the ability of the 5-HT antagonist, ritanserin, to alleviate schizophrenic symptoms and, when added to haloperidol (Haldol®), to decrease its extrapyramidal side-effects (EPS), have stimulated studies into a role of 5-HT in schizophrenia. The finding that clozapine (Leponex®), clinically superior to conventional neuroleptics, is a weak DA2 antagonist but a potent 5-HT1c and 5-HT2 antagonist has further stimulated 5-HT-related research in schizophrenia.

Recent life stressors and biological markers in newly admitted psychotic patients

The association of recent life stressor severity to putative biological markers of stress was examined in 34 newly admitted patients with acute psychosis. Of the biological variables examined, only pretreatment admission serum cortisol was correlated with stressor severity. Pretreatment serum prolactin, plasma homovanillic acid (HVA), and methoxyhydroxyphen-ethylglycol were not associated with severity of recent life stressors. We controlled for clinical and psychosocial variables that might affect the relationship of stressor severity to biological markers, and found that duration of psychotic symptoms was negatively correlated with stressor severity; however, when both cortisol and duration were entered in a stepwise multiple regression analysis, only pretreatment admission cortisol remained significantly and positively correlated with stressor severity. These findings suggest that serum cortisol may be a useful biological marker when investigating the relationship of life stress to episode onset. In addition, pretreatment HVA was correlated with early neuroleptic response but not with stressor severity, suggesting that HVA has value as a predictor of response independent of recent life stressors.

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.

Plasma homovanillic acid levels and therapeutic outcome in schizophrenics: comparisons of neuroleptic-naive first-episode patients and patients with disease exacerbation due to neuroleptic discontinuance

Plasma homovanillic acid (pHVA) levels were measured and the Brief Psychiatric Rating Scale (BPRS) scores were evaluated in 26 schizophrenic patients who had either never been medicated (neuroleptic-naive, first-episode subjects) or whose condition had become exacerbated following neuroleptic discontinuance (exacerbated subjects). All the subjects received medication with a fixed dose of a neuroleptic (haloperidol or fluphenazine, both 9 mg/day) for the first week and variable doses for the subsequent 4 weeks. In the neuroleptic-naive subjects, pHVA levels increased significantly 1 week after starting the protocol; this increase correlated significantly with clinical improvement of the BPRS positive symptom scores at week 5. In the neuroleptic-naive subjects, pHVA levels had declined to the baseline level by week 5. In the exacerbated subjects, there were no significant correlations between pHVA level changes at week 1 and later improvements of the BPRS positive symptom scores. These results suggest that the rise in pHVA levels occurring within 1 week after starting a fixed neuroleptic dose may predict a favorable clinical response in neuroleptic-naive schizophrenic patients.

Biologic markers and neurochemical correlates of agitation and psychosis in dementia

Behavioral and psychiatric symptoms frequently accompany the cognitive deterioration of dementia occurring in up to 80% of both community-based and nursing home patients. In Alzheimer's disease (AD), behavioral complications may develop at any stage of the disease process and tend to follow a more unpredictable course than the core cognitive symptoms. Over the past 15 years, our knowledge of the biologic and neurochemical basis of dementia, and of AD in particular, has increased significantly. Great emphasis has been placed on the cholinergic system abnormalities in the context of the cognitive impairment in AD and on the psychopharmalogic enhancement of cholinergic transmission in AD. However deficits in other neurotransmitter systems, such as the noradrenergic, serotonergic, and dopaminergic systems, also occur and may contribute to the core cognitive symptoms of AD. More recently, there has been increased interest in the biologic and neurochemical basis of behavioral and psychiatric disturbances in dementia. This article reviews the evidence for biologic and neurochemical correlates of psychosis and agitation in dementia, and discusses the treatment implications for these findings.

Monoamine activity reflected in urine of young patients with obsessive compulsive disorder, psychosis with and without reality distortion and healthy subjects: an explorative analysis

Positive psychotic symptoms are reported to be associated with high, negative symptoms with low dopamine (DA) activity and serotonin (5HT) activity may be altered in obsessive-compulsive disorder (OCD). We analysed 24 h urine samples in these patient groups and in healthy controls for supportive evidence. Young unmedicated OCD subjects excreted more adrenaline (AD) and homovanillic acid (HVA) and showed a higher HVA/MHPG ratio and metabolic rate than healthy controls. Independent of general metabolic rate they showed higher HVA concentrations which suggests that the relative activity of catecholamine systems in OCD (HVA/MHPG) is due more to high DA than to low noradrenergic (NA) activity. Concentrations of 5HT were also high in OCD patients. In psychotic patients low levels of DA, HVA, NA and MHPG probably resulted from neuroleptic medication. Patients diagnosed with paranoid psychosis showed higher DA utilization than controls and those with few paranoid symptoms showed high 5HT utilization. These results support studies suggesting that paranoid psychosis is associated more with increased DA activity (discussed in the context of neuroleptic reactivity), that non-paranoid forms are associated more with increased 5HT activity and that OCD patients are unusually aroused with high levels of Ad, 5HT and HVA.

Influence of renal clearance on peripheral homovanillic acid measurements in healthy subjects and schizophrenic patients

In order to investigate the effect of renal clearance on plasma homovanillic acid (HVA) concentrations, we examined plasma concentration and urinary excretion of HVA and creatinine per 4 h over 24 h in eight male schizophrenic patients and eight healthy male subjects. Renal clearances of HVA and of creatinine were determined per 4 h period. No significant differences were found between groups in the total 24 h excretion of either HVA or creatinine. Although differences between groups in plasma HVA concentrations and urinary HVA excretion per 4 h did not reach statistical significance, the renal clearance of HVA was significantly lower in the patient group than in the control group. There was no difference between groups in creatinine clearance. Diurnal changes were seen in the renal clearance of HVA and creatinine in both groups. Renal HVA clearance decreased from 23.00-07.00 h, with a coincident decrease in urinary HVA excretion and an increase in plasma HVA concentration. We provide evidence that renal clearance is an important determinant of plasma HVA concentration, and should be considered when interpreting plasma HVA data.

Plasma homovanillic acid in neuroleptic responsive and nonresponsive schizophrenics

Changes in plasma homovanillic acid (HVA) were investigated in neuroleptic responsive and nonresponsive schizophrenics in order to delineate parameters of dopamine regulation, which may underlie differences in neuroleptic responsivity. Nineteen schizophrenics were treated with haloperidol for 6 weeks. HVA was sampled at baseline, 24 hr after initial neuroleptic dose, and after 6 weeks of treatment. Subjects were pretreated with debrisoquin in order to reduce the peripheral production of HVA. The responders had an initial rise in HVA at 24 hr after first neuroleptic dose, followed by a decline back to baseline over the 6 weeks of treatment. The nonresponders' HVA failed to rise at 24 hr after first neuroleptic dose. At 6 weeks of treatment their HVA had fallen to significantly below baseline. Thus, a rise in HVA 24 hr after the first dose of neuroleptic predicted treatment response; a fall in HVA at 6 weeks to below pretreatment values was associated with neuroleptic nonresponse.

Haloperidol response and plasma catecholamines and their metabolites

Eleven acutely psychotic patients with schizophrenia or schizoaffective disorder underwent a 5-7 day drug-washout period (with lorazepam allowed) prior to participating in a 6-week controlled dose haloperidol trial. Patients were evaluated longitudinally with clinical ratings and with plasma measures of the catecholamines dopamine (pDA) and norepinephrine (pNE) and their metabolites, homovanillic acid (pHVA) and 3-methoxy-4-hydroxyphenylglycol (pMHPG). All patients exhibited clinical improvement with haloperidol; the decrease in their Brief Psychiatric Rating Scale (BPRS) scores ranged from 32 to 89%. Measures of pHVA increased within the first week of treatment and returned to baseline by week 5. The pattern of change of pDA resembled that of pHVA. The pattern of change of pNE and pMHPG revealed a decrease over the course of treatment. The early increase and the subsequent decrease in pHVA were strongly correlated with improvement in positive symptoms on the BPRS. These data are consistent with previous reports on the change in pHVA and pMHPG during clinical response to haloperidol. The data on change of pDA and pNE further describe the nature of the biochemical response to this drug.

Clozapine response and plasma catecholamines and their metabolites

The atypical neuroleptic clozapine has an unusual profile of clinical effects and a distinctive spectrum of pharmacological actions. Plasma measures of catecholamines and their metabolites have been used in the past to study the action of typical neuroleptics. We obtained longitudinal assessments of plasma measures of dopamine (pDA), norepinephrine (pNE), and their metabolites, homovanillic acid (pHVA) and 3-methoxy-4-hydroxyphenylglycol (pMHPG), in eight treatment-resistant or treatment-intolerant schizophrenic patients who were treated with clozapine for 12 weeks following a prolonged drug-washout period. Our findings from the study of these eight patients suggest the following: Plasma levels of HVA and possibly NE derived from the neuroleptic-free baseline period may predict response to clozapine; plasma levels of HVA and MHPG decrease during the initial weeks of treatment in responders but not in nonresponders; and plasma levels of DA and NE increase in both responders and nonresponders to clozapine.

Lithium in combination with perphenazine: effect on plasma monoamine metabolites

The addition of lithium to perphenazine altered the pattern of plasma homovanillic acid (HVA) during the course of treatment for acute psychosis. In the perphenazine-treated group plasma HVA declined significantly by days 7-9 of treatment, whereas in the perphenazine-plus-lithium group plasma HVA tended to increase. The pattern for plasma methoxyhydroxyphenethyl-glycol (MHPG) was not significantly different for the two groups. The addition of lithium to a neuroleptic may enhance the metabolism of dopamine.