During adolescence or adulthood, FRα autoimmunity can predispose to severe psychotic episodes and refractory schizophrenia characterized by marked FRα antibody titer fluctuations in cycles of 5–7 weeks which underlies either normal or lowered CSF folate values as a function of the FRα antibody titer at the time of the spinal tap. The gene discussed is FOLR1; the disease is schizophrenia.