Efficacy of N-methyl-D-aspartate receptor modulator augmentation in schizophrenia: A meta-analysis of randomised, placebo-controlled trials.

The results indicate that N-methyl-D-aspartate receptor modulators, particularly with glycine, D-serine and sarcosine, are more beneficial than the placebo in treating schizophrenia, and the effects extended to both positive and negative symptoms, when augmented with antipsychotics other than clozapine.