The prevalence of psychiatric symptoms a nd disorders in HIV-infected patie
nts is high. The differential diagnosis includes psychoreactive disorders,
acute psychiatric symptoms of an HIV-associated encephalopathy,and symptoma
tic psychotic illnesses due to secondary neurologic manifestations such as
opportunistic central nervous infections and intracerebral lymphoma. Clinic
al aspects and psychopathological findings are not sufficient for different
ial diagnosis and identification of primarily psychiatric disorders. Second
ary neurologic manifestations causing a symptomatic psychosis must be exclu
ded as soon as possible by brain imaging (CT,MRI) and analysis of the cereb
rospinal fluid. In emergency situations, however, German law imposes strict
regulations, especially in the case of sectioned patients. These medical a
nd medicolegal questions are illustrated by case reports and propositions f
or an effective strategy are made.