Common alterations in the serotonin transporter in platelets and lymphocytes of psychotic patients

Introduction: Given the controversial data concerning the role of the serotonin (5-HT) transporter in psychosis, our study was aimed to investigate this structure by means of the measurements of the re-uptake kinetics and of the protein density, in both platelets and lymphocytes of 25 out- and inpatients with different psychotic disorders. Methods: Diagnoses, according to DSM-IV criteria, were bipolar 1 disorders with mood incongruent psychotic features (14), mixed states (7) and schizophrenia (4). Twenty-five matched healthy subjects were also selected as the control group. Platelet and lymphocyte membranes were prepared according to standardized protocols, as were the [ 3H]5HT re-uptake and [3H]paroxetine ([3H]Par) binding. Results: The results of this study showed a decreased density of the [3H]Par binding sites coupled with a reduced velocity of [ 3H]5-HT re-uptake in both platelets and lymphocytes of psychotic patients, as compared with healthy control subjects. Conclusion: These findings would suggest a general abnormality of the 5-HT system in psychotic patients, probably not confined only to the brain.