Preliminary Analysis Of The Kynurenine Pathway Metabolites In Chronic Ketamine Users Compared With Those In Schizophrenic Patients

BackgroundKetamine can produce schizophrenia-like symptoms.The kynurenine(KYN)pathway was associated with schizophrenia.ContentsWe examined the serum kynurenine pathway metabolites kynurenic acid(KYNA),kynurenine and tryptophan(TRP)in chronic ketamine users and compared them with those in schizophrenic patients.The correlations of the metabolites with sociodemographic data,clinical characteristics and drug use status were analyzed.Method79 healthy controls,78 ketamine users and 80 schizophrenic patients were recruited.Serum TRP,KYN and KYNA levels were measured by high-performance liquid chromatography(HPLC)following tandem mass spectrometry(MS/MS).Psychotic symptoms were evaluated using the Positive and Negative Syndrome Scale(PANSS),the Beck Depression Inventory(BDI),and the Beck Anxiety Inventory(BAI).ResultsSerum levels of TRP,KYNA and KYN(in ketamine users only)were lower in ketamine users and schizophrenic patients than in controls(p<0.05).TRP and KYN were lower in ketamine users than in schizophrenic patients(p<0.01).KYNA levels were positively correlated with the current frequency of ketamine use in ketamine users(p=0.031),and serum KYNA levels were negatively correlated with the duration of schizophrenia(p=0.015).ConclusionsTRP,KYNA,and KYN were lower in chronic ketamine users than in controls,and the alterations were in the same direction as those observed in schizophrenic patients.