Schizophrenia bulletin
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Schizophrenia bulletin · Sep 2013
Randomized Controlled Trial Multicenter StudyEffects of risperidone and olanzapine dose reduction on cognitive function in stable patients with schizophrenia: an open-label, randomized, controlled, pilot study.
Impact of dose reduction of atypical antipsychotics on cognitive function has not been investigated in stable patients with schizophrenia. In this open-label, 28-week, randomized controlled trial, stable patients with schizophrenia treated with risperidone or olanzapine were randomly assigned to the reduction group (dose reduced by 50% in 4 weeks and then maintained) or maintenance group (dose kept constant). Assessments at baseline and week 28 included the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), Positive and Negative Syndrome Scale (PANSS), and Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). ⋯ This 6-month pilot study suggests that risperidone or olanzapine dose reduction of 50% can improve cognitive function for stable patients with schizophrenia. Due to the open-label design, small sample size, and short study duration, however, there is a need to confirm the finding through double-blind, larger scale trials with longer follow-up periods. Moreover, potential risks of relapse following antipsychotic dose reduction should be thoroughly investigated in longer term studies.
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Schizophrenia bulletin · Sep 2013
Comparative StudyWhen Broca goes uninformed: reduced information flow to Broca's area in schizophrenia patients with auditory hallucinations.
Auditory-verbal hallucinations (AVHs) are frequently associated with activation of the left superior temporal gyrus (including Wernicke's area), left inferior frontal gyrus (including Broca's area), and the right hemisphere homologs of both areas. It has been hypothesized that disconnectivity of both interhemispheric transfer and frontal and temporal areas may underlie hallucinations in schizophrenia. We investigated reduced information flow in this circuit for the first time using dynamic causal modeling, which allows for directional inference. ⋯ The connectivity magnitude in patients without hallucinations was found to be intermediate. Our results point toward a reduced input from temporal to frontal language areas in schizophrenia patients with AVH, suggesting that Broca's activity may be less constrained by perceptual information received from the temporal cortex. In addition, a lack of synchronization between Broca and its homolog may lead to the erroneous interpretation of emotional speech activity from the right hemisphere as coming from an external source.