Any intracranial space-taking lesion may have as its presenting complaint psychiatric symptoms. In some the psychiatric picture is the only or almost the only evidence of the disease. In mental institutions it has been shown that the incidence of brain tumor at autopsy averages in the neighborhood of 3.45%. Of these, approximately a third or more are benign tumors. Noninstitutional cases are cited wherein the symptoms prejudiced the first examing physician toward a psychiatric diagnosis.Abstract Teaser