Risperdal increases D-serine which augments stimulatory NMDA receptors:
D-serine improves negative symptoms and memory in the hippocampus:
“A recent meta-analysis found that GMS agonists, including d-serine, exert significant therapeutic effects on multiple symptom domains in schizophrenia in patients receiving antipsychotic medications, especially negative and cognitive symptoms”
“It was recently found that D-amino acid oxidase, the enzyme that catalyses the breakdown of D-amino acids (e.g. D-alanine and D-serine — the neurotransmitters) is inhibited by risperidone”