Natural Intracellular peptides were differentially expressed in ATL and CC of schizophrenia patients and healthy controls. Peptide fragments from neurogranin were altered in ATL and CC of schizophrenia patients. A histone H2B type 1-H peptide fragment was differentially expressed in ATL of schizophrenia patients. The fragment of histone H2B type 1-H was tested in Neuro2a cells and presented a promising cytoprotective effect. The results add evidence to the biological significance of endogenous intracellular peptides.