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. 2018 Oct 25;4(1):22.
doi: 10.1038/s41537-018-0064-6.

Efficacy of different types of cognitive enhancers for patients with schizophrenia: a meta-analysis

Affiliations

Efficacy of different types of cognitive enhancers for patients with schizophrenia: a meta-analysis

Igne Sinkeviciute et al. NPJ Schizophr. .

Abstract

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.

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Conflict of interest statement

Iris Sommer has received consultant fees from Gabather. The other authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Effects of cognitive enhancers on overall cognitive functioning

References

    1. Green MF, et al. Approaching a consensus cognitive battery for clinical trials in schizophrenia: the NIMH-MATRICS conference to select cognitive domains and test criteria. Biol. Psychiatry. 2004;56:301–307. doi: 10.1016/j.biopsych.2004.06.023. - DOI - PubMed
    1. Keefe RS, Fenton WS. How should DSM-V criteria for schizophrenia include cognitive impairment? Schizophr. Bull. 2007;33:912–920. doi: 10.1093/schbul/sbm046. - DOI - PMC - PubMed
    1. Kahn RS, Keefe RS. Schizophrenia is a cognitive illness: time for a change in focus. JAMA Psychiatry. 2013;70:1107–1112. doi: 10.1001/jamapsychiatry.2013.155. - DOI - PubMed
    1. Chang WC, Hui CL, Chan SK, Lee EH, Chen EY. Impact of avolition and cognitive impairment on functional outcome in first-episode schizophrenia-spectrum disorder: a prospective one-year follow-up study. Schizophr. Res. 2016;170:318–321. doi: 10.1016/j.schres.2016.01.004. - DOI - PubMed
    1. Strassnig MT, et al. Determinants of different aspects of everyday outcome in schizophrenia: The roles of negative symptoms, cognition, and functional capacity. Schizophr. Res. 2015;165:76–82. doi: 10.1016/j.schres.2015.03.033. - DOI - PMC - PubMed