Gary Remington

A Canadian multicenter placebo-controlled study of fixed doses of risperidone and haloperidol in the treatment of chronic schizophrenic patients.

In a double-blind study, 135 inpatients with a diagnosis of chronic schizophrenia were randomly assigned to 8 weeks of treatment with one of six parallel treatments: risperidone (a new central 5-hydroxytryptamine2 and dopamine D2 antagonist), 2, 6, 10, 16 mg/day; haloperidol, 20 mg/day; or placebo, after a single-blind placebo washout period. Doses were increased in fixed increments up to a fixed maintenance dose reached after 1 week. On the Clinical Global Impression-Severity of Illness and Improvement, all active medications were superior to placebo except for risperidone (2 mg) on the Clinical Global Impression-Improvement. On the total Positive and Negative Syndrome Scale (PANSS) score and positive subscale, superiority to placebo was observed for all treatment groups except for haloperidol and risperidone (2 mg), which tended to be superior to placebo on total PANSS and the positive subscale, respectively. On the PANSS negative subscale, only risperidone (6 mg/day) was significantly better than placebo. Risperidone (6 mg) was superior to haloperidol on the total PANSS, General Psychopathology, and Brief Psychiatric Rating Scale subscales. Although there was a linear increase in parkinsonism with increasing risperidone dosage, there were no statistically significant differences between risperidone (2, 6, and 16 mg/day) and placebo. At doses of 6 to 16 mg, risperidone displayed a marked antidyskinetic effect compared with placebo. This effect was more pronounced in patients with severe dyskinesia. By contrast, haloperidol produced significantly more parkinsonism than placebo and risperidone (2, 6 and 16 mg), with no effect on tardive dyskinesia. These data suggest that risperidone, at the optimal therapeutic dose of 6 mg/day, produced significant improvement in both positive and negative symptoms without an increase in drug-induced parkinsonian symptoms and with a significant beneficial effect on tardive dyskinesia.

Negative Symptoms in Schizophrenia: Avolition and Occam's Razor

The identification of schizophrenias negative symptoms dates back to the earliest descriptions of Kraepelin and Bleuler, who each highlighted the central role of avolition in the phenomenology and course of this illness. Since, there have been numerous advances in our understanding of schizophrenia, and the present review tracks the changes that have taken place in our understanding of negative symptoms, their description and measurement. That these symptoms represent a distinct domain of the illness is discussed in the context of their ties to other symptoms and functional outcome. The underlying structure of the negative symptom construct is explored, including several lines of investigation that point towards diminished expression and amotivation as key underlying subdomains. We also discuss findings of intact emotional experience and consummatory pleasure in individuals with schizophrenia, calling into question the presence of anhedonia in this illness. We conclude with a reconceptualization of the negative symptoms, suggesting amotivation (ie, avolition) represents the critical component, particularly in regard to functional outcome. Further exploration and clarification of this core deficit will ultimately enhance our neurobiological understanding of schizophrenia, as well as strategies that may improve outcome.

Characterizing coronary heart disease risk in chronic schizophrenia: high prevalence of the metabolic syndrome.

Objective: To determine the prevalence and characteristics of coronary heart disease (CHD) risk factors in patients with chronic schizophrenia or schizoaffective disorder. Method: We compared individual CHD risk factors and Framingham risk predictions in a group of 240 patients with a large national sample (Canadian Heart Health Survey) matched for age and sex. In addition, we compared rates of the metabolic syndrome (syndrome X) with recently published rates in the US adult population. Results: Compared with the reference population, Framingham 10-year risk of myocardial infarction was greater in the male patients (t3091 = 4.35, P < 0.001) but not in the female patients. Prevalence rates of the metabolic syndrome in the patients (42.6% of men and 48.5% of women) were approximately 2 times published rates in the US adult population. Further, the syndrome appears to occur at a younger age than in the general population. Conclusions: These long-term patients have increased CHD risks best captured by the metabolic syndrome conceptualization coupled with a high rate of cigarette smoking. This characterization is consistent with increased cardiovascular morbidity and decreased life expectancy in both men and women. We underscore the importance of both screening for and treating potentially reversible CHD risk factors in schizophrenia patients.

Validation of a physical activity assessment tool for individuals with schizophrenia

OBJECTIVE Increasing physical activity must be one component of lifestyle interventions designed to prevent or treat obesity in schizophrenia and there is now a need to develop low cost, practical and accurate measures of physical activity in this population to identify the prevalence of physical (in)activity and to assess the effectiveness of physical activity interventions. The objective of this study was to provide preliminary validation of the Short-Form International Physical Activity Questionnaire (IPAQ), a measurement tool that could prove useful for both clinicians and researchers in the field. METHOD Reliability and validity data were collected from a sample of 35 outpatients with a DSM-IV diagnosis of schizophrenia. Test-retest repeatability was assessed within the same week and criterion validity was assessed against an RT3 accelerometer. Spearmans correlation coefficients are reported based on the total reported physical activity (minutes) and estimated energy expenditure. RESULT We found a correlation coefficient of 0.68 for reliability and 0.37 for criterion validity based on total reported minutes of physical activity. There was a nonsignificant correlation (0.30; p>0.05) between the RT3 data and estimated energy expenditure derived from the IPAQ. CONCLUSION Although not without limitations, the Short-Form IPAQ, when used with individuals with schizophrenia, exhibits measurement properties that are comparable to those reported in the general population and can be considered as a surveillance tool to assess levels of physical activity.

Atypical antipsychotics: are some more atypical than others?

Abstract On the heels of clozapine, we now have a number of newer agents (risperidone, olanzapine, quetiapine, sertindole, and ziprasidone). Are they all the same? What are the differences? How do we best understand them? In this article we review current clinical evidence to compare these issues on four measures of atypicality: EPS, prolactin elevation, superior efficacy in refractory/positive symptoms and efficacy against negative symptoms. All the newer agents are superior on EPS and, with the exception of risperidone, avoid prolactin elevation. Clozapine shows the most convincing efficacy in refractory schizophrenia, although comparative data concerning risperidone’s benefit in this respect are also emerging. It is unclear, however, whether any of the agents produce a greater effect than conventional antipsychotics against positive symptoms in responsive patients. Both clozapine and olanzapine have demonstrated superior efficacy against negative symptoms, although it remains controversial whether this is an effect on primary or secondary symptoms. The precise pharmacologic mechanisms underlying ”atypicality” remain unclear, but several conceptual frameworks are highlighted that characterize, and perhaps differentiate, these newer agents.

Significant dissociation of brain and plasma kinetics with antipsychotics.

Current dosing regimens of psychotropic drugs are based on plasma kinetic considerations, although it is unclear whether plasma levels faithfully reflect brain kinetics of drugs.1,2 To examine this, we compared the kinetics of plasma levels of two widely used antipsychotics, olanzapine and risperidone, vs the time course of their effects in the brain. We used positron emission tomography (PET) and [11C]-labeled ligands to quantify striatal and extra-striatal dopamine-2 (D2), and cortical serotonin-2A (5-HT2A) receptor occupancy in healthy subjects after a single dose, and in patients chronically treated for psychosis. We found a significant dissociation of brain and plasma kinetics. Mean plasma elimination half-lives of single doses of olanzapine and risperidone were 24.2 and 10.3 h, respectively, whereas it took on average 75.2 h with olanzapine, and 66.6 h with risperidone to decline to 50% of their peak striatal D2 receptor occupancy. We found similar discrepancies between the time course of plasma levels and extra-striatal D2 as well as 5-HT2A receptor occupancy. Our results question the current reliance on plasma kinetics as the main basis for dosing regimens of antipsychotics. Studies of brain kinetics may provide a sounder basis for determining dosing schedules of psychotropic medications.

Increased Stress-Induced Dopamine Release in Psychosis

BACKGROUND A pathologic response to common life stressors, in which a hyperresponsive dopaminergic system is thought to play a key role, is a potential etiologic factor in the triggering and relapse of psychosis. However, there is no direct evidence that brain dopaminergic response to stress is exaggerated in psychosis. METHODS Using the ability of endogenous dopamine (DA) to compete with [(11)C]-(+)-PHNO binding, as measured with positron emission tomography, we examined stress-induced DA release in response to a validated psychosocial stress task. We studied 12 clinical high-risk (CHR), 10 antipsychotic-naive subjects with schizophrenia (SCZ), and 12 matched healthy volunteers (HV). Stress-induced DA release was estimated as the percent change in binding potential between conditions (stress and control scan) in the striatal subdivisions: limbic striatum (LST), associative striatum (AST), and sensorimotor striatum (SMST). RESULTS We found a significant difference between groups in the AST (F = 8.13, df = 2,31, p = .001), and at the SMST (F = 3,64, df = 2,31, p = .03) but not in the LST (F = .43, df = 2,31, p = .40) with CHR and SCZ having larger [(11)C]-(+)-PHNO displacement in response to the stress. Bonferroni-corrected comparisons confirmed that HV displacement (-2.86%) in the AST was significantly different in CHR (6.97%) and SCZ (11.44%) (with no significant difference between CHR and SCZ). CONCLUSIONS This study reveals a sensitized dopaminergic response to stress in a psychiatric condition and may have important theoretical and clinical implications regarding efforts to abort or delay relapse and/or conversion to psychosis.

Insight, neurocognitive function and symptom clusters in chronic schizophrenia.

Only recently has there been interest in the systematic study of insight in schizophrenia. The present investigation was designed to evaluate the specific relationship between psychopathological symptoms, neurocognitive deficits and awareness of illness in chronic schizophrenia. Fifty-eight outpatients with the DSM-III-R diagnosis of schizophrenia were rated on Davids Schedule for Assessing Insight, the Positive and Negative Syndrome Scale (PANSS), the Calgary Depression Scale and the Wisconsin Card Sorting Test (WCST). Results indicate that there is a significant association among these variables and that approximately 44% of the variance in the dependent variable could be explained by this combination of independent variables. Notably, however, negative symptoms were only moderately inversely correlated with awareness of illness, and they were not associated with scores on the WCST. Moreover, neither negative symptoms nor per cent perseverative errors contributed significantly to the prediction of insight in schizophrenia. These findings argue against the notion that unawareness of illness is the product of neuropsychological dysfunction in the frontal lobes. Instead, the most significant associations and predictors of insight were related to the positive symptoms of schizophrenia.

The relationship between D2 receptor occupancy and plasma levels on low dose oral haloperidol : a PET study

Abstract The purpose of this study was to determine the relationship between dopamine D2 receptor occupancy and plasma haloperidol. Twelve patients treated with 1–5 mg/day of haloperidol had their D2 occupancy measured using [11C]-raclopride and positron emission tomography and haloperidol plasma levels measured using gas chromatograph mass spectrophotometer. The patients exhibited haloperidol plasma levels ranging from 0.5 to 5.8 ng/ml and D2 occupancy from 53 to 88%. The D2 occupancy was related to the plasma level as a saturating rectangular hyperbola relationship (r2 = 0.84) and it showed that, on average, 50% D2 occupancy was achieved with 0.51 ng/ml and 80% D2 occupancy with 2.0 ng/ml. Our findings demonstrate that 2–5 mg/day of haloperidol, which usually leads to plasma levels of 1–2 ng/ml, would be expected to induce 60–80% dopamine D2 receptor occupancy. If, as has been claimed, 70% D2 occupancy is adequate for typical neuroleptic response, then the conventional use of >10 mg/day may have been too high, since 70% occupancy can be achieved in most patients by 2–5 mg/day. On the other hand, if as others have suggested, 8–12 ng/ml of haloperidol is the correct therapeutic window for plasma levels, then the required therapeutic D2 occupancy is closer to 90%, not 70%. The implications of the D2 occupancy findings for the optimal dosing of neuroleptics are discussed.

Incentive motivation deficits in schizophrenia reflect effort computation impairments during cost-benefit decision-making

BACKGROUND Motivational impairments are a core feature of schizophrenia and although there are numerous reports studying this feature using clinical rating scales, objective behavioural assessments are lacking. Here, we use a translational paradigm to measure incentive motivation in individuals with schizophrenia. METHODS Sixteen stable outpatients with schizophrenia and sixteen matched healthy controls completed a modified version of the Effort Expenditure for Rewards Task that accounts for differences in motoric ability. Briefly, subjects were presented with a series of trials where they may choose to expend a greater amount of effort for a larger monetary reward versus less effort for a smaller reward. Additionally, the probability of receiving money for a given trial was varied at 12%, 50% and 88%. Clinical and other reward-related variables were also evaluated. RESULTS Patients opted to expend greater effort significantly less than controls for trials of high, but uncertain (i.e. 50% and 88% probability) incentive value, which was related to amotivation and neurocognitive deficits. Other abnormalities were also noted but were related to different clinical variables such as impulsivity (low reward and 12% probability). These motivational deficits were not due to group differences in reward learning, reward valuation or hedonic capacity. CONCLUSIONS Our findings offer novel support for incentive motivation deficits in schizophrenia. Clinical amotivation is associated with impairments in the computation of effort during cost-benefit decision-making. This objective translational paradigm may guide future investigations of the neural circuitry underlying these motivational impairments.