Reduction of cerebrospinal fluid and plasma serotonin in patients with post-stroke depression: A preliminary report.

OBJECTIVE To investigate the plasma and cerebrospinal fluid (CSF) concentrations of serotonin in patients with post-stroke depression (PSD). METHODS Serotonin was measured in 30 PSD patients and 30 controls on day 15 and day 30 following stroke. RESULT There was a good correlation between the plasma and the CSF serotonin concentrations in both PSD (r = 0.641, P = 0.001) and control patients (0.852, P = 0.001) 30 days following the stroke. The average plasma and CSF serotonin concentrations in the PSD patients were lower than in the control group on day 15 (CSF: 0.24+/-0.27 vs 0.82+/-0.48 micromol/L, P < 0.01; plasma, 0.32+/-0.25 vs 0.83+/-0.45micromol/L, P < 0.01) and day 30 (CSF: 0.29+/-0.23 vs 0.78+/-0.47 micromol/L, P < 0.01; plasma, 0.31+/-0.33 vs 0.89+/-0.67 micromol/L, P < 0.01). Reduction of plasma serotonin was found in 90.0% of the PSD group and 13.3% of the control group patients (P < 0.01). Reduction in CSF serotonin in the PSD and control group was 80.0% and 6.7% respectively (P < 0.01%). CONCLUSION Plasma serotonin levels may be used to represent the CSF serotonin levels in depressed and non-depressed patients following stroke. There is a reduction in the plasma or CSF serotonin concentrations in patients with PSD. Serotonin deficiency may be one of the factors leading to depression following stroke.