The PIK3CD gene encodes the delta catalytic subunit of phosphoinositide 3-kinase (PI3K), an element of the neuregulin 1-downstream ErbB4-PI3K signaling pathway, which was recently identified as a molecular target for the treatment of schizophrenia. The aim of the study was to examine the effect of haloperidol (HALO), clozapine (CLO), olanzapine (OLA), quetiapine (QUE) and amisulpride (AMI) on the mRNA and protein expression of genes encoding the elements of ErbB4-PI3K pathway, in a human central nervous system cell line. The U-87MG human glioblastoma cell line was used as an experimental model. Quantitative polymerase chain reaction was used to examine the expression of mRNA and enzyme-linked immunosorbent assay for protein expression. At concentrations reached in clinical settings in the brain, CLO, as well as OLA and QUE to a lesser extent, but not AMI and probably not HALO, decreased the mRNA expression of PIK3CD. Protein expression of the gene did not confirm the mRNA expression profile. The tested antipsychotic drugs (APDs) in the U-87MG glioblastoma cell line differentially regulates the mRNA expression of PIK3CD; however, the protein expression does not confirm these findings. The results of the study may help deepen the understanding of the mechanism of action of APDs.