Tetrahydrobiopterin deficiency in schizophrenia: Biochemical and clinical aspects

It was reported that the levels of tetrahydrobiopterin (BH4) are reduced in schizophrenia. However, mechanisms of BH4 deficiency in schizophrenia had not been studied precisely.

the search of the association between BH4 deficiency in schizophrenia and a range of biochemical and clinical parameters for the evaluation of the possible mechanisms of BH4 loss and its role in the development of the symptoms.

93 patients with schizophrenia and 60 healthy volunteers were randomly selected and evaluated with a biochemical examination of BH4, folate, cobalamin (B12), homocysteine, C-reactive protein (CRP), reduced glutathione (GSH) levels in the blood serum.Patients underwent standardized psychopathological examination.

In patients, the levels of BH4 and folate were lower (p = 0.001 and p = 0.054, respectively), and the levels of homocysteine were higher (p = 0.012) compared to the control group. BH4 levels directly moderately correlated with folate (ρ = 0.43; p = 0.0029) and B12 levels (ρ = 0.43; p = 0.0020) and inversely moderately correlated with homocysteine levels (ρ = -0.54; p = 0.00015) in patients. Cluster analysis identified schizophrenia biotype characterized by a deficiency of BH4, folate, B12, and hyperhomocysteinemia. The clinical characteristics of this biotype were not specific. CRP and GSH were higher in patients compared to controls, but their association with serum BH4 was not confirmed.