The topic of antipsychotic-induced weight-gain and its relationship to glucose metabolism is under-studied. We evaluated the long-term effects of a new-generation antipsychotic, quetiapine and a conventional antipsychotic, haloperidol on body mass index (BMI) and glycaemic control in patients with schizophrenia previously treated with conventional antipsychotics. Forty-five clinically stable patients with schizophrenia participated in this randomized, investigator-blinded, parallel-group comparison of flexible doses of quetiapine and haloperidol treatment over 52 wk. Primary outcome measures were change from baseline in BMI and glycosylated haemoglobin (HBA1c) levels. There were no between-group differences at any of the time-points for BMI (F=1.90, p=0.1) and HBA1c (F=1.17, p=0.3) values, and there were no significant changes in BMI from baseline for either group. HBA1c levels decreased significantly at end-point for the haloperidol group (-1.5%, p=0.04), but not for the quetiapine group (-0.3%, p=0.5). Although the sample was not generally obese (mean baseline BMI 25.5+/-6.3 kg/m2), a large proportion exhibited evidence of abnormal glycaemic control prior to randomization (mean HBA1c 6.7+/-1.9%), with 48% having values that were at least mildly elevated (HBA1c >6.1%) and 19% markedly elevated (HBA1c >7%). The number of subjects with elevated HBA1c values decreased from baseline in both the haloperidol and quetiapine treatment groups. These findings suggest that switching treatment from a conventional antipsychotic to quetiapine is not associated with weight gain or worsening of glycaemic control, even in the long term. The study also highlights the high incidence of unrecognized glucose dysregulation in patients with schizophrenia receiving conventional antipsychotic treatment.

Experimental studies have demonstrated that the GABAergic system modulates acetylcholine release and, through GABAA receptors, tonically inhibits cholinergic activity. Little is known about the effects of GABA on the cholinergic activity in the human central nervous system. In vivo evaluation of some cholinergic circuits of the human brain has recently been introduced using a transcranial magnetic stimulation (TMS) protocol based on coupling peripheral nerve stimulation with TMS of the motor cortex. Peripheral nerve inputs have an inhibitory effect on motor cortex excitability at short intervals (short latency afferent inhibition, SAI). We investigated whether GABAA activity enhancement by lorazepam modifies SAI. We also evaluated the effects produced by lorazepam on a different TMS protocol of cortical inhibition, the short interval intracortical inhibition (SICI), that is believed to be directly related to GABAA activity. In ten healthy volunteers, the effects of lorazepam were compared with those produced by quetiapine, a psychotropic drug with sedative effects with no appreciable affinity at cholinergic muscarinic and benzodiazepine receptors, and with those of a placebo using a randomized double-blind study design. Administration of lorazepam produced a significant increase in SICI [F(3,9)=3.19, p=0.039]. In contrast to SICI, SAI was significantly reduced by lorazepam [F(3,9)=9.39, p=0.0002]. Our findings demonstrate that GABAA activity enhancement determines a suppression of SAI and an increase of SICI.

OBJECTIVE: This study examines total pharmacy cost and usage patterns of schizophrenic patients in acute mental health inpatient settings for three atypical antipsychotics -- risperidone, olanzapine, and quetiapine. Despite the readily available unit cost information for drugs, actual pharmacy costs may deviate significantly from 'labeled costs'. Recent research findings indicate the need for more robust evaluation of such pharmacy costs. RESEARCH DESIGN AND METHODS: This study used data from non-randomized inpatient retrospective charts from three acute care inpatient mental health facilities. The final pooled sample included 327 patients, of which 120 received risperidone, 153 received olanzapine, and 54 received quetiapine. Medication cost was defined as the average wholesale price (AWP) as listed in the 2001 'Red Book'. Propensity scoring methodology and multinomial regression were employed to reduce treatment selection bias. RESULTS: The observed mean daily antipsychotic drug doses were 4.45 mg (SD 2.44) for risperidone, 14.04 mg (SD 5.55) for olanzapine, and 350.33 mg (SD 228.24) for quetiapine. The corresponding mean daily drug costs were $7.66(SD $4.20) for risperidone, $8.11 (SD $5.29) for quetiapine and, $12.10 (SD $4.79) for olanzepine. Numbers adjusted for treatment selection bias show that the average daily total pharmacy cost of risperidone was $4.35 lower than olanzapine (p < 0.001) and $1.41 lower than quetiapine (p = 0.38). The adjusted average daily pharmacy cost of olanzapine was $4.02 higher than quetiapine (p < 0.001). After statistical adjustment there were no significant differences between study drugs in terms of length of stay or patient functioning. CONCLUSION: This study provides the first US comparison of medication utilization patterns and pharmacy costs for olanzapine, risperidone, and quetiapine administered in acute mental health care inpatient settings. While this study did not estimate the full economic value of the three antipsychotics in these inpatient settings, it demonstrated that the mean daily costs for risperidone were lower than the mean daily costs for olanzapine (p < 0.001) and quetiapine although the later difference was not statistically significant (p = 0.38).