Platelet serotonin reuptake inhibition and response to SSRIs in depressed adolescents.

Objective: The authors examined platelet serotonin reuptake inhibition and response to selective serotonin reuptake inhibitor (SSRI) treatment in depressed adolescents.

Method: Twenty-three depressed adolescents participating in pharmacokinetic studies of SSRIs had platelet serotonin reuptake measured before and after 14-28 days of treatment. The Clinical Global Impression (CGI) improvement rating was determined on the basis of all clinical information and was performed blind to the platelet data.

Results: Improvement in depressive symptoms as rated with the CGI improvement subscale was significantly associated with the percentage change in platelet serotonin reuptake inhibition from pre- to posttreatment. Improvement in depression was also associated with absolute decrease in platelet serotonin reuptake when adjusted for the magnitude of baseline reuptake.

Conclusions: Platelet serotonin reuptake inhibition may be an appropriate surrogate biological marker for the pharmacodynamic activity of SSRIs in depressed adolescents.