Psychiatric features may occur in individuals with metabolic disorders. A review is made on the diagnostic characteristics of the main metabolic inborn errors that show psychiatric symptoms. A five year literature search with the terms “mental disorders” and “metabolism, inborn errors” on Medline and Lilacs, retrieved no Latin publication. Case reports and reviews on the subject in the international literature were reviewed. A inborn error of metabolism should be suspected in a person with a psychiatric disorder unresponsive to the proper therapy, or in those that present with other features of the metabolic diseases.