[Neurologic and psychologic disorders in folic acid deficiency]

Folic acid deficiency is the most common of all vitamin deficiencies in North America and in Western Europe, usually in association with other vitamin deficiencies. Alcoholism is considered to be the most frequent cause of folic acid deficiency, as far as the Western world is concerned. Severe neurological and mental disturbances can develop in case of folate deficiency probably long before the manifestation of macrocythaemia. Among the neurological sequelae of folic acid deficiency the main phenomena that are discussed as likely are polyneuropathy, funicular disease of the spine and restless legs. The psychic or mental symptoms that can be ascribed to folic acid deficiency are non-specific and correspond with the symptoms of a psychosis that can have physical causes. Administration of folic acid has repeatedly resulted in significant improvements of neurological and mental symptoms in folic acid deficiency. The exact mechanisms involved in a damage to the nervous system are not sufficiently clarified for folic acid deficiency. Diagnosis is effected mainly by determining the folic acid concentration in the serum. Daily administration of approx. 1.25-15 mg folic acid (oral and/or parenteral) is recommended. Mild side effects such as tiredness and irritability have been noted only with high folic acid dosage levels.