Folic Acid deficiency is considered to play a role in patients with Schizophrenia. Serum or plasma concentration of folic acid is substantially lower in individuals with Schizophrenia than in the general population (Cao et al., 2016).
Mutations in key enzymes that regulate folic acid levels have been demonstrated as a moderator between folic acid levels and severity of negative symptoms in individuals with Schizophrenia (Nishi et al., 2014).
A systemic review of meta analyses revealed substantial improvements in negative symptoms in individuals with schizophrenia who were given folic acid supplementation (Sakuma et al., 2018).
Cao B., Wang D.F., Xu M.Y., Liu Y.Q., Yan L.L., Wang J.Y., Lu Q.B. (2016) Lower folate levels in schizophrenia: a meta-analysis. Psychiatry Res 245:1–7
Nishi A., Numata S., Tajima A., Kinoshita M., Kikuchi K., Shimodera S., Tomotake M., Ohi K., Hashimoto R., Imoto I., Takeda M., Ohmori T. (2014) Meta-analyses of blood homocysteine levels for gender and genetic association studies of the MTHFR C677T polymorphism in schizophrenia. Schizophrenia Bulletin 40:1154–1163
Sakuma, K., Matsunaga, S., Nomura, I., Okuya, M., Kishi, T., & Iwata, N. (2018). Folic acid/methylfolate for the treatment of psychopathology in schizophrenia: a systematic review and meta-analysis. Psychopharmacology, 235(8), 2303-2314. doi:10.1007/s00213-018-4926-4