Cognitive impairment is a core feature of schizophrenia, which is predictive for functional outcomes and is, therefore, a treatment target in itself. Yet, literature on efficacy of different pharmaco-therapeutic options is inconsistent. This quantitative review provides an overview of studies that investigated potential cognitive enhancers in schizophrenia. We included pharmacological agents, which target different neurotransmitter systems and evaluated their efficacy on overall cognitive functioning and seven separate cognitive domains. In total, 93 studies with 5630 patients were included. Cognitive enhancers, when combined across all different neurotransmitter systems, which act on a large number of different mechanisms, showed a significant (yet small) positive effect size of 0.10 (k = 51, p = 0.023; 95% CI = 0.01 to 0.18) on overall cognition. Cognitive enhancers were not superior to placebo for separate cognitive domains. When analyzing each neurotransmitter system separately, agents acting predominantly on the glutamatergic system showed a small significant effect on overall cognition (k = 29, Hedges’ g = 0.19, p = 0.01), as well as on working memory (k = 20, Hedges’ g = 0.13, p = 0.04). A sub-analysis of cholinesterase inhibitors (ChEI) showed a small effect on working memory (k = 6, Hedges’ g = 0.26, p = 0.03). Other sub-analyses were positively nonsignificant, which may partly be due to the low number of studies we could include per neurotransmitter system. Overall, this meta-analysis showed few favorable effects of cognitive enhancers for patients with schizophrenia, partly due to lack of power. There is a lack of studies involving agents acting on other than glutamatergic and cholinergic systems, especially of those targeting the dopaminergic system.

认知障碍是精神分裂症的核心特征，可预测功能结果，因此本身就是治疗的目标。然而，关于不同药物治疗选择的疗效的文献并不一致。这项定量综述提供了研究精神分裂症潜在认知增强剂的研究概述。我们纳入了针对不同神经递质系统的药理剂，并评估了它们对整体认知功能和七个独立认知域的功效。总共纳入了93项研究，涉及5630例患者。当认知促进剂跨所有不同的神经递质系统结合时，它们作用于许多不同的机制，显示出显着的（但很小的）正面效应大小为0.10（k  = 51，p = 0.023; 95％CI = 0.01至0.18）。对于单独的认知域，认知增强剂并不优于安慰剂。当单独分析每个神经递质系统，谷氨酸能系统上主要作用剂显示出对整体认知（小显著效果ķ  = 29，套期克 =  0.19，p  = 0.01），以及对工作记忆（ķ  = 20，树篱（g  ＝ 0.13，p  ＝ 0.04）。胆碱酯酶抑制剂的子分析（CHEI）显示对工作记忆的影响小（ķ  = 6，树篱克 = 0.26，p = 0.03）。其他子分析没有积极意义，部分原因是我们可以针对每个神经递质系统进行的研究数量较少。总体而言，这项荟萃分析显示，对于精神分裂症患者而言，认知增强剂的有益作用极少，部分原因是缺乏力量。缺乏涉及除谷氨酸能和胆碱能系统以外的药物，特别是针对多巴胺能系统的药物的研究。