Alterations of the cerebrospinal fluid (CSF) protein contents and the blood brain barrier (BBB) in schizophrenia have been observed by several authors but no relationship to clinical characteristics like psychopathology, the course or the duration of the disease could be described until now. We have studied 27 schizophrenic patients upon each of whom a lumbar punction had been carried out for clinical reasons. The average values of the patients were within the normal range. Nine patients (33%) showed the total protein content to be > 45 mg% and 6 (22%) > 50 mg%. In the latter 6 patients an impaired BBB (raised albumin CSF/serum quotient) and in 4 patients (15%) a raised CSF immunoglobulin (IgG) were observed. No relation to the patient's age and the duration of the disease was found but correlations with the Scale for the Assessment of Negative Symptoms (SANS) showed significant results in the subscores affective flattening/affective blunting , alogia/paralogia as well as in the total score with respect to the CSF contents of albumin and IgG (p=0.009-0.02). These correlations suggest that the CSF albumin and the CSF IgG are related to the negative symptomatology in schizophrenia and that patients with these CSF alterations may have a higher risk of developing negative symptoms.