Serotonin uptake to lymphocytes of patients with social phobia compared to normal individuals

Several trials have indicated that selective serotonin reuptake inhibitors (SSRIs) are most efficient in the treatment of social phobia (SP). The activity of the serotonin transporter (5-HTT), as determined by [3H]5-HT uptake to blood lymphocytes, was measured in 15 drug-free patients with generalized SP (7M/8F, aged 21–37 years) and compared to 18 healthy control subjects (10M/8F, aged 21–32 years). The maximum uptake velocity (Vmax) of [3H]5-HT to fresh lymphocytes and the affinity (Km) of the 5-HTT were similar in the two groups (295 ± 155 versus 227 ± 117 pmol/min/mg protein and 767 ± 425 versus 709 ± 408 nM, respectively). This study suggests that the functioning of lymphocyte 5-HTT is unaltered in SP.