Platelet paroxetine binding in major depressive disorder with and without comorbid obsessive-compulsive disorder

Platelet ³H-paroxetine binding measures were compared in three age-matched groups each containing 11 individuals: a group with DSM-III-R major depressive disorder (MDD) and comorbid obsessive-compulsive disorder (OCD), a group with DSM-III-R MDD alone, and a psychiatrically screened normal comparison group. No differences were found between groups in B_max values. The patients with MDD only were found to have significantly higher K_d values than either the group with comorbid OCD or the normal subjects. No significant correlations were found between binding measures and either depressive or OCD symptoms. Our data suggest that inconsistencies remain in the literature on ³H-imipramine binding in OCD and that a variety of confounding factors may explain them. Duration of illness, for example, may be one such factor as decreases in uptake site number tend to dissipate with longer duration of illness.