Effectiveness of antipsychotic drugs in patients with chronic schizophrenia

BACKGROUND

The relative effectiveness of second-generation (atypical) antipsychotic drugs as compared with that of older agents has been incompletely addressed, though newer agents are currently used far more commonly. We compared a first-generation antipsychotic, perphenazine, with several newer drugs in a double-blind study.

METHODS

A total of 1493 patients with schizophrenia were recruited at 57 U.S. sites and randomly assigned to receive olanzapine (7.5 to 30 mg per day), perphenazine (8 to 32 mg per day), quetiapine (200 to 800 mg per day), or risperidone (1.5 to 6.0 mg per day) for up to 18 months. Ziprasidone (40 to 160 mg per day) was included after its approval by the Food and Drug Administration. The primary aim was to delineate differences in the overall effectiveness of these five treatments.

RESULTS

Overall, 74 percent of patients discontinued the study medication before 18 months (1061 of the 1432 patients who received at least one dose): 64 percent of those assigned to olanzapine, 75 percent of those assigned to perphenazine, 82 percent of those assigned to quetiapine, 74 percent of those assigned to risperidone, and 79 percent of those assigned to ziprasidone. The time to the discontinuation of treatment for any cause was significantly longer in the olanzapine group than in the quetiapine (P<0.001) or risperidone (P=0.002) group, but not in the perphenazine (P=0.021) or ziprasidone (P=0.028) group. The times to discontinuation because of intolerable side effects were similar among the groups, but the rates differed (P=0.04); olanzapine was associated with more discontinuation for weight gain or metabolic effects, and perphenazine was associated with more discontinuation for extrapyramidal effects.

CONCLUSIONS

The majority of patients in each group discontinued their assigned treatment owing to inefficacy or intolerable side effects or for other reasons. Olanzapine was the most effective in terms of the rates of discontinuation, and the efficacy of the conventional antipsychotic agent perphenazine appeared similar to that of quetiapine, risperidone, and ziprasidone. Olanzapine was associated with greater weight gain and increases in measures of glucose and lipid metabolism.

Impaired fasting glucose tolerance in first-episode, drug-naive patients with schizophrenia

OBJECTIVE

This study examined the prevalence of impaired fasting glucose tolerance in first-episode, drug-naive patients with schizophrenia.

METHOD

In this cross-sectional study, fasting plasma levels of glucose, insulin, lipids, and cortisol were measured in 15 male and 11 female hospitalized Caucasian patients with DSM-IV schizophrenia (mean age=33.6 years) and age- and sex-matched healthy comparison subjects. The patients and comparison subjects were also matched in terms of various life-style and anthropometric measures.

RESULTS

More than 15% of the drug-naive, first-episode patients with schizophrenia had impaired fasting glucose tolerance, compared to none of the healthy volunteers. Compared with the healthy subjects, the patients with schizophrenia had significantly higher fasting plasma levels of glucose (mean=88.2 mg/dl, SD=5.4, for the healthy subjects versus mean=95.8 mg/dl, SD=16.9, for the patients), insulin (mean=7.7 micro u/ml, SD=3.7, versus mean=9.8 micro u/ml, SD=3.9), and cortisol (mean=303.2 nmol/liter, SD=10.5, versus mean=499.4 nmol/liter, SD=161.4) and were more insulin resistant, as measured with homeostasis model assessment (mean=1.7, SD=0.7, for the healthy subjects versus mean=2.3, SD=1.0, for the patients).

CONCLUSIONS

First-episode, drug-naive patients with schizophrenia have impaired fasting glucose tolerance and are more insulin resistant and have higher levels of plasma glucose, insulin, and cortisol than healthy comparison subjects.

Decreased serum levels of D-serine in patients with schizophrenia: evidence in support of the N-methyl-D-aspartate receptor hypofunction hypothesis of schizophrenia

BACKGROUND

The hypofunction of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors has been implicated in the pathophysiology of schizophrenia. Several lines of evidence suggest that D-serine may function as an endogenous agonist of the glycine site of the NMDA receptor. The aim of this study was to examine whether serum levels of D- and L-serine in patients with schizophrenia are different from those of healthy controls.

METHODS

Forty-two patients with schizophrenia and 42 age- and sex-matched healthy controls were enrolled in this study. Symptoms were assessed using the Brief Psychiatric Rating Scale. Serum levels of total serine and D- and L-serine were measured by high-performance liquid chromatography.

RESULTS

Serum levels of D-serine in the patients with schizophrenia were significantly (z = -3.30, P =.001) lower than those of healthy controls. In contrast, serum levels of total (D and L) serine (z = -2.40, P =.02) and L-serine (z = -2.49, P =.01) in the schizophrenic patients were significantly higher than those of controls. In addition, the percentage of D-serine in the total serine in the schizophrenic patients was significantly (z = -4.78, P<.001) lower than that of controls, suggesting that the activity of serine racemase, an enzyme catalyzing the formation of D-serine from L-serine, may have been reduced in the schizophrenic patients.

CONCLUSIONS

Reduced levels of D-serine may play a role in the pathophysiology of schizophrenia, and serum D- and L-serine levels might provide a measurable biological marker for schizophrenia.

Serum thyrotropin response to thyrotropin-releasing hormone in psychiatric patients: a review

In 1972 it was reported that in some euthyroid depressed patients the serum thyrotropin (TSH) response to thyrotropin-releasing hormone (TRH) was deficient. Since then, 41 reports describing 917 depressed patients have confirmed this finding. Although it is useful to report differences between mean response values of patient populations, it is necessary to identify those individuals in whom the fault occurs so that sensitivity, specificity, state-trait distribution, and clinical correlates can be determined. Present data allow some tentative conclusions: 1) the fault usually reflects a defect in central regulation of the pituitary-thyroid axis, 2) in some patients the fault may be a trait marker, and 3) it may represent a biological bridge between some depressed patients and some patients with other mental disorders.

Diet, smoking and cardiovascular risk in people with schizophrenia: descriptive study

BACKGROUND

Physical health of people with schizophrenia is poor and they die early from cardiovascular disease.

AIMS

To describe the lifestyle of people with schizophrenia through diet, smoking habits, weight and exercise, and to report risk of coronary heart disease (CHD).

METHOD

Dietary habits of 102 community-dwelling people with schizophrenia were assessed by the Scottish Health Survey Questionnaire. Also assessed were smoking habits, physical activity, biochemical indices of nutrition and future risk of CHD.

RESULTS

Fewer males, compared with the general population, reached acceptable levels for consumption of fruit, vegetables, milk, potatoes and pulses. Fewer females reached the levels for consumption of milk and potatoes. Mean number of fruit and vegetable portions consumed per week was 16 (s.d.=14); 71 (70%) were smokers; 25 (86%) females and 50 (70%) males were over weight or obese; 59 (59%) considered themselves physically active; 46 (53%) had a raised cholesterol: high-density lipoprotein ratio, and 64 (74%) a low alpha-tocopherol: cholesterol ratio. Mean 10-year risk of CHD in males was 10.5% (s.d.=8) and in females 7% (s.d.=6).

CONCLUSIONS

The lifestyle of people with schizophrenia must give cause for concern in relation to CHD. Care from concern in relation to secondary care services must address physical as well as mental health.

Efficacy of high-dose glycine in the treatment of enduring negative symptoms of schizophrenia

BACKGROUND

Disturbances of N-methyl-D-aspartate (NMDA) receptor-mediated glutamatergic neurotransmission may play an important role in the pathophysiology of negative symptoms of schizophrenia. Glycine, a small nonessential amino acid, functions as an obligatory coagonist at NMDA receptors through its action at a strychnine-insensitive binding site on the NMDA receptor complex. Glycine-induced augmentation of NMDA receptor-mediated neurotransmission may thus offer a potentially safe and feasible approach for ameliorating persistent negative symptoms of schizophrenia.

METHODS

Twenty-two treatment-resistant schizophrenic patients participated in a double-blind, placebo-controlled, 6-week, crossover treatment trial with 0.8 g/kg per day of glycine added to their ongoing antipsychotic medication. Clinical assessments, including the Brief Psychiatric Rating Scale (BPRS), the Positive and Negative Syndrome Scale (PANSS), the Simpson-Angus Scale for Extrapyramidal Symptoms, and the Abnormal Involuntary Movement Scale, were performed biweekly throughout the study. Clinical laboratory values and amino acid serum levels were monitored.

RESULTS

Glycine treatment was well tolerated and induced increased glycine (P=.001) and serine (P=.001) serum levels. Glycine administration resulted in (1) a significant (P<.001) 30%+/-16% reduction in negative symptoms, as measured by the PANSS, and (2) a significant (P<.001) 30%+/-18% improvement in the BPRS total scores. The improvement in negative symptoms was unrelated to alterations in extrapyramidal effects or symptoms of depression. Low pretreatment glycine serum levels significantly predicted (r= 0.80) clinical response.

CONCLUSION

These findings support hypoglutamatergic hypotheses of schizophrenia and suggest a novel approach for the pharmacotherapy of negative symptoms associated with this illness.

Effect of clonidine on growth hormone release in psychiatric patients and controls

The stimulation of human growth hormone (HGH) release by clonidine (0.15 mg i.v.) was studied as a test of the postsynaptic alpha-receptor sensitivity of psychiatric patients. In this test, endogenous depressives showed a significantly reduced HGH response to clonidine as compared to normal controls, neurotic-reactive depressives, and schizophrenics. However, no differences were found between the endogenous depressives and a group of schizoaffective patients. HGH response to clonidine was not correlated with plasma levels of noradrenaline, serum cortisol, free fatty acids, or blood glucose. Within the group of normal control subjects, a reduced HGH response was found in most postmenopausal women and in some regular users of alcohol. Our findings suggest that patients with endogenous depression are characterized by a subsensitivity of postsynaptic alpha-receptors or of structures related to them. The clonidine test shows promise as an indicator of vulnerability to endogenous depression.

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.

Enhancement of recovery from psychiatric illness by methylfolate

41 (33%) of 123 patients with acute psychiatric disorders (DSM III diagnosis of major depression or schizophrenia) had borderline or definite folate deficiency (red-cell folate below 200 micrograms/l) and took part in a double-blind, placebo-controlled trial of methylfolate, 15 mg daily, for 6 months in addition to standard psychotropic treatment. Among both depressed and schizophrenic patients methylfolate significantly improved clinical and social recovery. The differences in outcome scores between methylfolate and placebo groups became greater with time. These findings add to the evidence implicating disturbances of methylation in the nervous system in the biology of some forms of mental illness.

D-serine efficacy as add-on pharmacotherapy to risperidone and olanzapine for treatment-refractory schizophrenia

BACKGROUND

D-serine, a selective full agonist at the glycine site of N-methyl-D-aspartate glutamate receptor, might presently be the compound of choice for counteracting the hypothesized dysfunction of this receptor class in schizophrenia. Studies performed with Taiwanese patients indicate that D-serine significantly improves schizophrenia symptoms when used as adjuvant to conventional neuroleptics but not to clozapine. We assessed the efficacy and safety of D-serine adjuvant treatment for Occidental schizophrenia patients treated with newer atypical antipsychotics.

METHODS

Thirty-nine risperidone- or olanzapine-treated schizophrenia patients participated in a double-blind, placebo-controlled, 6-week crossover trial with 30 mg/kg/day D-serine added to their antipsychotic medication. Measures of clinical efficacy and side effects were determined biweekly throughout the study. Clinical laboratory parameters and amino acid serum levels were monitored.

RESULTS

D-serine administration induced increased serine serum levels (p < .001) and resulted in significant (p < .001) improvements in negative, positive, cognitive, and depression symptoms, as measured by the Positive and Negative Syndrome Scale. For approximately one third of the sample, D-serine treatment resulted in significant (>20%) reductions in Brief Psychiatric Rating Scale total scores. D-serine was well tolerated, and no detrimental changes in clinical laboratory parameters were noted.

CONCLUSIONS

These findings 1) indicate that risperidone and olanzapine efficacy might be augmented with D-serine adjuvant treatment; 2) confirm D-serine efficacy against main schizophrenia symptom domains; and 3) warrant the assessment of D-serine antipsychotic monotherapy for this illness.

Hypothalamic-pituitary-adrenal axis activity in depressive illness. Its relationship to classification

Serum cortisol response to the 1-mg overnight dexamethasone suppression test was studied in 221 depressed patients and 109 nondepressed psychiatric controls. Nonsuppression distinguished patients with primary unipolar depression (65/146) from patients with secondary unipolar depression (0/42) and nondepressed controls (0/109). Furthermore, nonsuppression distinguished the three familial subtypes of primary unipolar depressive illness: familial pure depressive disease (FPDD; 38/50 patients), sporadic depressive disease (SDD; 24/55 patients), and depression spectrum disease (3/41 patients). Moderate elevations in baseline serum cortisol levels were found in FPDD, SDD, and bipolar depression. Medication did not affect the results. The data suggest that the depressive syndrome is composed of separate illnesses, each of which has a distinctive pattern of hypothalamic-pituitary-adrenal axis activity during the depressed state as well as a specific clinical and familial psychiatric history.

Interleukin-6-(IL-6) plasma levels in depression and schizophrenia: comparison between the acute state and after remission

The concentration of cytokines such as Interleukin-6 (IL-6) has been reported to be elevated in depressed and schizophrenic patients and, in healthy persons, upon stress. Interleukin-6 plasma levels were determined in depressed (n = 12) and schizophrenic (n = 32) patients during the acute state of illness and after remission at approximately 8 weeks after admission and were compared with healthy controls (n = 12). Patients were diagnosed according to DSM-III-R by the Structured Clinical Interview (SCID). Severity of illness was assessed for depression by the Montgomery Asberg Depression Rating Scale (MADRS) and for schizophrenia by the Brief Psychiatric Rating Scale (BPRS). Interleukin-6 plasma concentrations were elevated during the acute state either of depression or of schizophrenia if compared to controls. After remission, IL-6 concentrations in depressed and in schizophrenic patients had decreased and did not differ significantly from controls. We hypothesize that the elevated IL-6 levels during the acute state of depression or schizophrenia may reflect an unspecific stress response.

Plasma protein biomarkers for depression and schizophrenia by multi analyte profiling of case-control collections

Despite significant research efforts aimed at understanding the neurobiological underpinnings of psychiatric disorders, the diagnosis and the evaluation of treatment of these disorders are still based solely on relatively subjective assessment of symptoms. Therefore, biological markers which could improve the current classification of psychiatry disorders, and in perspective stratify patients on a biological basis into more homogeneous clinically distinct subgroups, are highly needed. In order to identify novel candidate biological markers for major depression and schizophrenia, we have applied a focused proteomic approach using plasma samples from a large case-control collection. Patients were diagnosed according to DSM criteria using structured interviews and a number of additional clinical variables and demographic information were assessed. Plasma samples from 245 depressed patients, 229 schizophrenic patients and 254 controls were submitted to multi analyte profiling allowing the evaluation of up to 79 proteins, including a series of cytokines, chemokines and neurotrophins previously suggested to be involved in the pathophysiology of depression and schizophrenia. Univariate data analysis showed more significant p-values than would be expected by chance and highlighted several proteins belonging to pathways or mechanisms previously suspected to be involved in the pathophysiology of major depression or schizophrenia, such as insulin and MMP-9 for depression, and BDNF, EGF and a number of chemokines for schizophrenia. Multivariate analysis was carried out to improve the differentiation of cases from controls and identify the most informative panel of markers. The results illustrate the potential of plasma biomarker profiling for psychiatric disorders, when conducted in large collections. The study highlighted a set of analytes as candidate biomarker signatures for depression and schizophrenia, warranting further investigation in independent collections.

Impaired glucose tolerance in first-episode drug-naïve patients with schizophrenia

AIMS

To determine whether there is an association between Type 2 diabetes mellitus and schizophrenia, independent of medication.

METHODS

In this cross-sectional study we performed an oral glucose tolerance test on 38 non-obese white Caucasians who fulfilled the criteria for first-episode drug-naïve schizophrenia, 38 control subjects (matched for age, gender, smoking status, alcohol intake and ethnicity) and 44 first-degree relatives of the patients.

RESULTS

The frequency of impaired glucose tolerance (IGT), defined by World Health Organization criteria, was 10.5% (n = 4) in patients with schizophrenia, 18.2% (n = 8) in unaffected relatives and 0.0% in healthy control subjects (chi(2) = 4.22, d.f. = 2, P < 0.05).

CONCLUSIONS

The high point prevalence of IGT in never-treated patients and relatives supports either shared environmental or genetic predisposition to IGT. Both patients and their relatives present an ideal cost-effective opportunity to screen for Type 2 diabetes mellitus, as they are both easily identifiable.

Glucose metabolism in patients with schizophrenia treated with atypical antipsychotic agents: a frequently sampled intravenous glucose tolerance test and minimal model analysis

BACKGROUND

While the incidence of new-onset diabetes mellitus may be increasing in patients with schizophrenia treated with certain atypical antipsychotic agents, it remains unclear whether atypical agents are directly affecting glucose metabolism or simply increasing known risk factors for diabetes.

OBJECTIVE

To study the 2 drugs most clearly implicated (clozapine and olanzapine) and risperidone using a frequently sampled intravenous glucose tolerance test.

DESIGN

A cross-sectional design in stable, treated patients with schizophrenia evaluated using a frequently sampled intravenous glucose tolerance test and the Bergman minimal model analysis.

SETTING

Subjects were recruited from an urban community mental health clinic and were studied at a general clinical research center. Patients Fifty subjects signed informed consent and 41 underwent the frequently sampled intravenous glucose tolerance test. Thirty-six nonobese subjects with schizophrenia or schizoaffective disorder, matched by body mass index and treated with either clozapine, olanzapine, or risperidone, were included in the analysis.

MAIN OUTCOME MEASURES

Fasting plasma glucose and fasting serum insulin levels, insulin sensitivity index, homeostasis model assessment of insulin resistance, and glucose effectiveness.

RESULTS

The mean +/- SD duration of treatment with the identified atypical antipsychotic agent was 68.3 +/- 28.9 months (clozapine), 29.5 +/- 17.5 months (olanzapine), and 40.9 +/- 33.7 (risperidone). Fasting serum insulin concentrations differed among groups (F(33) = 3.35; P = .047) (clozapine>olanzapine>risperidone) with significant differences between clozapine and risperidone (t(33) = 2.32; P = .03) and olanzapine and risperidone (t(33) = 2.15; P = .04). There was a significant difference in insulin sensitivity index among groups (F(33) = 10.66; P<.001) (clozapine<olanzapine<risperidone), with subjects who received clozapine and olanzapine exhibiting significant insulin resistance compared with subjects who were treated with risperidone (clozapine vs risperidone, t(33) = -4.29; P<.001; olanzapine vs risperidone, t(33) = -3.62; P = .001 [P<.001]). The homeostasis model assessment of insulin resistance also differed significantly among groups (F(33) = 4.92; P = .01) (clozapine>olanzapine>risperidone) (clozapine vs risperidone, t(33) = 2.94; P = .006; olanzapine vs risperidone, t(33) = 2.42; P = .02). There was a significant difference among groups in glucose effectiveness (F(30) = 4.18; P = .02) (clozapine<olanzapine<risperidone) with significant differences between clozapine and risperidone (t(30) = -2.59; P = .02) and olanzapine and risperidone (t(30) = -2.34, P = .03).

CONCLUSIONS

Both nonobese clozapine- and olanzapine-treated groups displayed significant insulin resistance and impairment of glucose effectiveness compared with risperidone-treated subjects. Patients taking clozapine and olanzapine must be examined for insulin resistance and its consequences.

Acute phase proteins in schizophrenia, mania and major depression: modulation by psychotropic drugs

Recently, an acute phase (AP) protein response has been reported in major depression. In order to examine whether an AP response occurs in other psychiatric disorders, such as schizophrenia and mania, the authors measured plasma AP reactants, such as haptoglobin (Hp), immunoglobulin G (IgG), IgM, fibrinogen (Fb), complement component 3 (C3C), C4, alpha 1-antitrypsin (alpha 1 AT), alpha 1-acid-glycoprotein (alpha 1S) and hemopexin (Hpx), in 27 schizophrenic, 23 manic, 29 major depressed and 21 normal subjects. Schizophrenic patients had significantly higher plasma Hp, Fb, C3C, C4, alpha 1S and Hpx than normal controls. Manic subjects showed significantly higher plasma Hp, Fb, alpha 1S and Hpx than normal volunteers. Depressed subjects had significantly higher plasma Hp, Fb, C3C, C4 and alpha 1S than normal controls. Overall, the above disorders in AP reactants were more pronounced in schizophrenic than in depressed subjects. No significant differences in the above AP reactants could be found between normal volunteers, and schizophrenic, manic or depressed patients who underwent chronic treatment with psychotropic drugs. Plasma Hp, Fb, C3C, C4, alpha 1S, and Hpx were significantly higher in schizophrenic, manic and depressed patients who were non-medicated than in those who were treated with antidepressants, antipsychotics or lithium. The results suggest that not only major depression but also schizophrenia and mania are accompanied by an AP response, and that the latter may be suppressed by (sub)chronic treatment with psychotropic drugs.

Longitudinal measurement of plasma homovanillic acid levels in schizophrenic patients. Correlation with psychosis and response to neuroleptic treatment

The plasma levels of homovanillic acid (HVA), a major circulating dopamine (DA) metabolite, were measured in schizophrenic patients during five weeks each of double-blind placebo-controlled neuroleptic treatment (N = 16) and withdrawal (N = 11). Both neuroleptic treatment and withdrawal were associated with time-dependent changes in the plasma levels of HVA; treatment was associated with decreases and withdrawal with increases. The levels of plasma HVA measured longitudinally during both conditions were highly correlated with psychosis ratings. Moreover, changes in individual mean weekly levels of plasma HVA were predictive of treatment response, including changes in both positive and negative symptoms of schizophrenia. These data are consistent with the suggestion that the mechanisms of action of antipsychotic drugs involve, in addition to short-term DA receptor blockade, a slowly developing decrease in presynaptic DA activity.

What is an adequate trial with clozapine?: therapeutic drug monitoring and time to response in treatment-refractory schizophrenia

Clozapine is the gold standard and 'last resort' in treatment of refractory schizophrenia. It is important to know whether a trial with clozapine is adequate or not. Six studies show a significantly higher response rate at clozapine plasma trough levels above a therapeutic threshold of 350-400 micro g/L. The absolute risk reduction is about 40%. An additional study found best results with plasma levels between 300 and 700 micro g/L, and one (probably too small) study could not detect a significantly different response rate for 350-450 micro g/L in comparison to 200-300 micro g/L. In addition, two extension studies showed conversion from nonresponders to responders if plasma levels increased above the threshold. Investigations on time to response in treatment with clozapine are often hampered by not controlling for time until plateau of dose titration or clozapine concentration. One of the better studies found 34 responders within 8 weeks after the last dose escalation. The remaining 16 non-responding patients did not change their status during a mean follow-up of 75 weeks. A second 1 year trial found a superior differential response rate for clozapine in comparison to haloperidol only during the first 6 weeks. A third study combined regular clozapine plasma level assays with assessment of response status. At the time of response 17 out of 19 responders showed clozapine concentrations above 350 micro g/L. The nine non-responders remained below this threshold throughout the rest of the year. These results favour an approach of raising the clozapine plasma level in treatment-refractory schizophrenic patients who do not respond to an initial low-to-medium dose treatment with clozapine. Some patients, especially young male smokers, will need dosages higher than 900 mg/day. Addition of low-dose fluvoxamine while closely monitoring clozapine levels can help decrease the high number of necessary pills. An adequate trial with clozapine should last at least 8 weeks on a plasma trough level above 350-400 micro g/L.

The effect of neuroleptics on serum prolactin in schizophrenic patients

Serum prolactin levels were studied before and during long-term administration of phenothiazines on a twice daily schedule to 27 newly admitted schizophrenic patients. An increase in serum prolactin is believed to be a reflection of inhibition of dopamine receptors in the hypothalamopituitary axis. By 72 hours after the initiation of treatment, all 27 patients had persistently elevated serum prolactin levels averaging 3.2-fold and 3.8-fold in men and women, respectively. There was a lag between clinical response and dopamine blockade, as indicated by serum prolactin levels in most patients. Serum prolactin levels remained elevated during the one- to three-month period subjects were studied, suggesting there was no tolerance to this effect of phenothiazines. Serum prolactin levels tended to be higher with thioridazine than on equivalent doses of chlorpromazine or trifluoperazine hydrochloride. There was some evidence that the magnitude of the serum prolactin elevation correlated with clinical response. After cessation of phenothiazines, serum prolactin levels rapidly reverted to normal within 48 to 96 hours.

Prenatal exposure to a repeated variable stress paradigm elicits behavioral and neuroendocrinological changes in the adult offspring: potential relevance to schizophrenia

Exposure to stress during gestation induces marked changes in the behavior of the affected offspring. Examining the consequences of prenatal stress may prove useful in understanding more about the origins of schizophrenia because a number of clinical investigations have suggested that developmental insults are associated with an increased incidence of schizophrenia. The purpose of these studies is to investigate the effects of stress during gestation on the behaviors of the adult male rat offspring with an emphasis on developing a heuristic animal model of schizophrenia. Pregnant female Sprague-Dawley rats were exposed to a novel variable stress paradigm during either the second or third week of gestation. Behavioral and neuroendocrinological consequences of prenatal stress exposure were evaluated in the male offspring on postnatal day 35 or 56. Prenatal stress exposure during the third week of pregnancy caused adult male rats to exhibit prolonged elevation in plasma glucocorticoid levels following acute exposure to restraint stress indicative of diminished glucocorticoid negative feedback. Similarly, exposure to stress during the third week of pregnancy elicited an enhanced locomotor response to the psychomotor stimulant amphetamine on postnatal day 56 but not on postnatal day 35. In addition, prepulse inhibition of the acoustic startle response was diminished across a range of prepulse stimulus intensities in prenatally stressed adult male rats. Similarly, prenatally stressed rats showed evidence of a disruption in auditory sensory gating as measured by the N40 response. Taken together, these findings suggest that prenatal stress exposure significantly changed many facets of adult rat behavior. Interestingly, the behaviors that are altered have been used to validate animal models of schizophrenia and therefore, suggest that this preparation may be useful to learn more about some aspects of the pathophysiology of schizophrenia.

Reduced erythrocyte membrane essential fatty acids and increased lipid peroxides in schizophrenia at the never-medicated first-episode of psychosis and after years of treatment with antipsychotics

Abnormal membrane phospholipid essential polyunsaturated fatty acid (EPUFA) metabolism (i.e., reduced incorporation into phospholipids and increased breakdown) has been suggested to contribute to the etiopathophysiology of schizophrenia. However, most of the published studies have reported changes in the levels of membrane EPUFA in chronic medicated patients or in drug-naive patients long after onset of illness (1-2 years). Since the EPUFA metabolism can be altered by years of untreated illness or differentially altered by various antipsychotics, the significance of EPUFA membrane status to schizophrenia psychopathophysiology is unclear. We report the erythrocyte membrane EPUFA levels in drug-naive patients within +/- 4.5 days of onset of psychosis from an Army Medical Center, and in patients treated years with antipsychotics from a Veterans Affairs Medical Center. The levels of plasma lipid peroxides (TBARS, thiobarbituric acid reactive substances), products of damaged EPUFAs, were also determined. The levels of EPUFAs, particularly arachidonic acid (AA) and docosahexaenoic acid (DHA) were significantly lower (P < 0.001) in drug-naive patients at the onset of psychosis compared to matched normal controls. These lower EPUFA levels were associated with significantly higher levels of TBARS in patients (P < 0.001). The levels of AA and DHA were also lower (P < 0.001) and TBARS higher in chronic medicated patients than normal controls. However, the EPUFA levels were higher in chronic medicated patients than drug-naive first-episode patients. These data indicate that lower membrane AA and DHA most likely predate the illness and probably contribute to the onset of illness, and furthermore treatment with some antipsychotics may increase the levels of EPUFAs. The lipid peroxidation data suggest that possible increased oxidative stress, either as a part of the illness and/or its treatment with antipsychotics, may be one of the mechanisms of reduced membrane EPUFAs. These findings may have a significant impact on improving strategies for supplementation of EPUFAs and antioxidants to improve the outcome of schizophrenia.

Reduced monoamine oxidase activity in platelets: a possible genetic marker for vulnerability to schizophrenia

Monoamine oxidase activity in blood platelets was measured, with [(14)C]tryptamine as substrate, in 13 monozygotic twin pairs discordant for schizophrenia and in 23 normal volunteers. The monoamine oxidase activity of both schizophrenic and nonschizophrenic co-twins was significantly lower than it was for the normals, and it was highly correlated between twins. In addition, there was a significant inverse correlation between a measure of the degree of the schizophrenic disorder and the monoamine oxidase activity. These data suggest, but do not prove, that reduced platelet monoamine oxidase activity may provide a genetic marker for vulnerability to schizophrenia.

Toxoplasma gondii and schizophrenia

Recent epidemiologic studies indicate that infectious agents may contribute to some cases of schizophrenia. In animals, infection with Toxoplasma gondii can alter behavior and neurotransmitter function. In humans, acute infection with T. gondii can produce psychotic symptoms similar to those displayed by persons with schizophrenia. Since 1953, a total of 19 studies of T. gondii antibodies in persons with schizophrenia and other severe psychiatric disorders and in controls have been reported; 18 reported a higher percentage of antibodies in the affected persons; in 11 studies the difference was statistically significant. Two other studies found that exposure to cats in childhood was a risk factor for the development of schizophrenia. Some medications used to treat schizophrenia inhibit the replication of T. gondii in cell culture. Establishing the role of T. gondii in the etiopathogenesis of schizophrenia might lead to new medications for its prevention and treatment.