Project description:The association of antipsychotic medication with abnormal brain morphometry in schizophrenia remains uncertain. This study investigated subcortical morphometric changes 6 months after switching treatment to clozapine in patients with treatment-resistant schizophrenia compared with healthy volunteers, and the relationships between longitudinal volume changes and clinical variables. In total, 1.5T MRI images were acquired at baseline before commencing clozapine and again after 6 months of treatment for 33 patients with treatment-resistant schizophrenia and 31 controls, and processed using the longitudinal pipeline of Freesurfer v.5.3.0. Two-way repeated MANCOVA was used to assess group differences in subcortical volumes over time and partial correlations to determine association with clinical variables. Whereas no significant subcortical volume differences were found between patients and controls at baseline (F(8,52) = 1.79; p = 0.101), there was a significant interaction between time, group and structure (F(7,143) = 52.54; p < 0.001). Corrected post-hoc analyses demonstrated that patients had significant enlargement of lateral ventricles (F(1,59) = 48.89; p < 0.001) and reduction of thalamus (F(1,59) = 34.85; p < 0.001), caudate (F(1,59) = 59.35; p < 0.001), putamen (F(1,59) = 87.20; p < 0.001) and hippocampus (F(1,59) = 14.49; p < 0.001) volumes. Thalamus and putamen volume reduction was associated with improvement in PANSS (r = 0.42; p = 0.021, r = 0.39; p = 0.033), SANS (r = 0.36; p = 0.049, r = 0.40; p = 0.027) and GAF (r = -0.39; p = 0.038, r = -0.42; p = 0.024) scores. Reduced thalamic volume over time was associated with increased serum clozapine level at follow-up (r = -0.44; p = 0.010). Patients with treatment-resistant schizophrenia display progressive subcortical volume deficits after switching to clozapine despite experiencing symptomatic improvement. Thalamo-striatal progressive volumetric deficit associated with symptomatic improvement after clozapine exposure may reflect an adaptive response related to improved outcome rather than a harmful process.

Project description:BACKGROUND:Aripiprazole is a relatively new antipsychotic drug, said to be the prototype of a new third generation of antipsychotics; the so-called dopamine-serotonin system stabilisers. In this review we examine how the efficacy and tolerability of aripiprazole differs from that of typical antipsychotics. OBJECTIVES:To evaluate the effects of aripiprazole compared with other typical antipsychotics for people with schizophrenia and schizophrenia-like psychoses. SEARCH STRATEGY:We searched the Cochrane Schizophrenia Group Trials Register (November 2007) which is based on regular searches of BIOSIS, CENTRAL, CINAHL, EMBASE, MEDLINE and PsycINFO. We inspected references of all identified studies for further trials. We contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information. SELECTION CRITERIA:We included all randomised trials comparing aripiprazole with typical antipsychotics in people with schizophrenia or schizophrenia-like psychosis. DATA COLLECTION AND ANALYSIS:We extracted data independently. For dichotomous data we calculated relative risks (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis, based on a random effects model. We calculated numbers needed to treat/harm (NNT/NNH) where appropriate. For continuous data, we calculated weighted mean differences (WMD) again based on a random effects model. We have contacted representatives of Bristol Myers Squibb pharmaceuticals (UK) for additional data. MAIN RESULTS:We included nine randomised trials involving 3122 people comparing aripiprazole with typical antipsychotic drugs. None of the studies reported on relapse - our primary outcome of interest. Attrition from studies was high and data reporting poor. Participants given aripiprazole were comparable to those receiving typical drugs in improving global state and mental state. Aripiprazole provided a significant advantage over typical antipsychotics in terms of fewer occurrences of extra-pyramidal symptom (n=968, 3 RCT, RR 0.46 CI 0.3 to 0.9, NNT 13 CI 17 to 10), and particularly akathisia (n=897, 3 RCT, RR 0.39 CI 0.3 to 0.6, NNT 11 CI 14 to 9). Fewer participants given aripiprazole developed hyperprolactinaemia (n=300, 1 RCT, RR 0.07 CI 0.03 to 0.2, NNT 2 CI 3 to 1). Aripiprazole presented a lesser risk of sinus tachycardia (n=289, 1 RCT, RR 0.09 CI 0.01 to 0.8, NNT 22 CI 63 to 13) and blurred vision (n=308, 1 RCT, RR 0.19 CI 0.1 to 0.7, NNT 14 CI 25 to 10); but enhanced risk of occurrence of dizziness (n=957, 3 RCT, RR 1.88 CI 1.1 to 3.2, NNH 20 CI 33 to 14) and nausea (n=957, 3 RCT, RR 3.03 CI 1.5 to 6.1, NNH 17 CI 25 to 13). Attrition rates were high in both groups, although significantly more participants in the aripiprazole group completed the study in the long term (n=1294, 1 RCT, RR 0.81 CI 0.8 to 0.9 NNT 8 CI 5 to 14). AUTHORS' CONCLUSIONS:Aripiprazole differs little from typical antipsychotic drugs with respect to efficacy, however it presents significant advantages in terms of tolerability. Clearly reported pragmatic short, medium and long term randomised controlled trials are required to replicate and validate these findings and determine the position of aripiprazole in everyday clinical practice.

Project description:Up to one-third of those with schizophrenia fail to respond to standard antipsychotics and are considered to have treatment-resistant schizophrenia, a condition for which clozapine is the only evidence-based medication. While up to 60% of treated individuals obtain therapeutic benefits from clozapine, it is currently underprescribed worldwide, partly because of concerns related to its broad adverse effect profile. In particular, the potential effects of clozapine on the immune system have gained relevance after a recent study showed that drug plasma concentrations were inversely correlated with neutrophil counts in individuals routinely undergoing treatment. Seeking to investigate this relationship in more detail, we extracted metabolic, immune, and genetic data from a UK cohort of long-term clozapine users linked to a clozapine monitoring service, CLOZUK2 (N = 208). Whilst a correlation analysis was compatible with the original results, a multiple linear regression accounting for dose and other confounding factors additionally allowed us to estimate the decrease in absolute neutrophil counts to approximately 141 cells/mm3 for every 0.1 mg/L increase in clozapine concentration. However, this association was attenuated after controlling for the metabolic ratio between clozapine and its main metabolite, norclozapine, which was itself negatively associated with neutrophil concentrations. Further analyses revealed that these relationships are likely moderated by genetic factors, as three pharmacogenomic SNPs previously associated to norclozapine plasma concentrations and the metabolic ratio (rs61750900, rs2011425 and rs1126545) were shown to be independently associated with a variation in neutrophil counts of about 400 cells/mm3 per effect allele. Such results are compatible with an effect of norclozapine, but not necessarily clozapine, on immune cell counts, and highlight the need for further investigations into the potential role of genetic determinants of clozapine pharmacokinetics in the occurrence of adverse effects during treatment.

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Clozapine combined with different antipsychotic drugs for treatment-resistant schizophrenia.

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