[Neurosyphilis as differential diagnosis in psychiatry].

A 46-year-old previously healthy man was referred to a psychiatric department after debuting with persecutory delusions. He had symptoms of Parkinson's disease as well as a significant impairment of memory and cognitive function. Neurological tests detected discrete balance and rigidity problems. Paraclinical tests were normal, and neurologists explained the symptoms as side effects to the antipsychotic medication. A lumbar puncture showed high concentrations of leukocytes and protein, and syphilis screening was positive. Neurosyphilis often debuts with psychiatric symptoms as seen in this case.