There is a paper titled ‘Antipsychotic Effects on Cognition in Schizophrenia: A Meta-Analysis of Randomised Controlled Trials’ by Brodbeck and colleagues and freely available here. The authors were interested in the benefit of antipsychotics on cognition in people with schizophrenia and give their reasoning for choosing a meta-analytic approach to answer this question. The inclusion criteria are clearly stated and the authors have selected randomised controlled trials comparing an atypical with a typical antipsychotic in the treatment of schizophrenia, schizoaffective or schizophreniform disorder. The neurocognitive measures are also stated in the inclusion criteria and the authors go on to give a detailed description of the methodology including the qualifiers for the medline search such that the reader may easily replicate or update the meta-analysis search phase using the stated search terms. Interestingly the returned papers are assessed using independent raters and they make use of amongst other measures, the Jadad scale which is briefly outlined. The statistical analysis is similarly detailed and includes the calculation and combination of effect sizes based on post-treatment comparisons. The authors also examine the effects of outliers and control for possible publication bias. Eighteen relevant studies were identified and analysed. The authors find a small and significant advantage for the atypicals over typicals in ‘language, speed of processing and psychomotricity’. However in the discussion they advise due caution over the results by demonstrating that a number of the effect sizes are small and that larger studies show smaller effect sizes. They also speculate about possible mechanisms based on D2 receptors, acetylcholine and dopamine release in the prefrontal cortex. Interestingly they also suggest that there should be a stricter age stratification in future studies and although they suggest 16 > < 55 years as an appropriate age range there is a case to be made for other age ranges including >65 years as well as a comparison between age stratified populations to identify emerging phenomenon. This is a concise, clearly written paper which is easily reproducible and informative.
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