Abnormal expression of serotonin transporter mRNA in the frontal and temporal cortex of schizophrenics.

Postmortem brain tissue was used to measure expression of serotonin transporter mRNA in the left frontal and left temporal cortex from schizophrenics (n = 24) and from normal control individuals with no history of psychiatric illness (n = 10). There was an approximately four-fold increase of serotonin transporter mRNA in Brodmann's area 9 and a two-fold decrease in Brodmann's areas 21 and 22. The changes in serotonin transporter mRNA were more prominent in schizophrenics who had received neuroleptic drugs within 1 week prior to death than in schizophrenics who were neuroleptic-free for more than 2 weeks prior to death, suggesting that the changes may be related to neuroleptic treatment. There was no correlation between serotonin transporter mRNA levels and the sex or age of schizophrenic and control cases or the postmortem delay intervals. These results support the hypothesis that region-specific changes in serotonin transporter expression occur in brains of some schizophrenics. Future studies are necessary to determine whether the changes in serotonin transporter expression are drug-related or are associated with the illness itself.