Relationship between abnormal brainstem auditory-evoked potentials and subnormal CSF levels of HVA and 5-HIAA in first-episode schizophrenic patients.
Auditory brainstem-evoked responses (ABRs) were recorded and the CSF concentration of the amine metabolites homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were measured in 39 drug-free schizophrenic patients. Twenty-four of the patients were first admissions and had never received antipsychotic medication. The ABRs were judged according to our normative data and the CSF concentrations of the amine metabolites were compared with those of 47 healthy volunteers. Clear-cut abnormal ABRs, identified as a lack of one or more peaks or abnormal peak latencies, were found in 15 patients. In controls and patients with normal ABRs, there was a significant positive correlation between the cerebrospinal fluid (CSF) levels of HVA and 5-HIAA; no such correlation was found in patients with abnormal ABRs. Schizophrenics with abnormal ABRs had significantly lower levels of HVA, but not 5-HIAA, in the CSF when compared with controls. Schizophrenic patients with normal ABRs (n = 24) did not differ from the controls with regard to the amine metabolites in CSF. A comparison of the CSF levels of HVA and 5-HIAA yielded no significant difference between patients with normal and those with abnormal ABRs. In contrast, when only first-episode, never-treated schizophrenics were considered, patients with abnormal ABRs (n = 10) had significantly lower levels of both HVA and 5-HIAA when compared with those having normal ABRs (n = 14). The results indicate an association between brainstem dysfunction and reduced central nervous dopaminergic and possibly also serotoninergic activity in schizophrenia.