Neurosyphilis remains a differential diagnosis for a wide variety of psychiatric syndromes, including dementia, mood disorders and psychosis. However, the incidence of neurosyphilis presenting initially with psychiatric symptomalogy is unclear. In this article, a clinical case is reported so as to illustrate some of the issues involved.

A 33-year-old married man was admitted because of a depressive episode associated with somatic preoccupations and a gradual loss of ability to function a year prior to his admission. The symptoms described above raised the question of an organic brain syndrome associated with the psychotic depression. Some laboratory and additional examinations were performed. Serological tests for syphilis were positive for both the hemagglutination test, Treponema pallidum hemaglutination (TPHA), and the immunofluorescent antibody test, fluorescent treponemal antibody-absorption (FTA-ABS). Based on these findings, the diagnosis of neurosyphilis was made. The patient was treated with benzathine penicillin (2 400 000 units i.m. once a week) for 3 weeks and venlafaxine (150 mg daily) and olanzapine (5 mg daily). His depression disappeared gradually, and he was discharged in partial remission.

High-risk groups such as patients with neuropsychiatric diseases should be screened with serological tests so as to prevent morbidity and help eliminate syphilis.