Effects of antipsychotics on amino acid levels in patients with first-episode schizophrenia: A prospective study

Background and objectives

Alterations in the molecular mechanisms of specific amino acids (AAs) may be implicated in the pathophysiology of schizophrenia (SZ). However, little is known about antipsychotic drugs influence on levels of AAs. This study aimed to further explore antipsychotics' effects on AAs and serum lipid levels in first-episode SZ.

Methods

Eighty subjects with the International Classification of Diseases, Tenth Edition (ICD-10) criteria-defined SZ were enrolled. The levels of 31 AAs were measured in plasma samples using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Results

Ten AAs (i.e., citrulline, sarcosine, tyrosine, leucine, proline, hydroxyproline, kynurenine, tryptophan, valine and isoleucine) were observed to be higher and three AAs (i.e., GABA, aminobutyric acid and asparaginic acid) were lower in 80 patients with first-episode SZ after various antipsychotics treatment. In addition, there were 1 out of 31 AAs altered after olanzapine treatment and there were only 2 out of 31 AAs altered after risperidone treatment. Furthermore, serum triglyceride (TG) was markedly upregulated after olanzapine treatment, while Apolipoprotein A1 (ApoA1) was generally upregulated after risperidone treatment in patients with first-episode SZ.

Conclusions

Taken together, antipsychotic treatment can affect the plasma levels of AAs in patients with first-episode SZ, and olanzapine and risperidone have differential effects on the levels of AAs.