Changes in serotonergic parameters have been reported in psychiatric conditions 
such as depression but also in the premenstrual dysphoric disorder (PMDD). In 
addition, hormonal effects on serotonergic activity have been established. In 
the present study, binding of [3H]paroxetine to platelet serotonin uptake sites 
and binding of [3H]lysergic acid diethylamide ([3H]LSD) to platelet serotonin 
(5-HT)2A receptors were studied in patients with PMDD treated with a low dose of 
a gonadotropin releasing hormone (GnRH) agonist (buserelin) or placebo and 
compared to controls. The PMDD patients were relieved of premenstrual symptoms 
like depression and irritability during buserelin treatment. The number of 
[3H]paroxetine binding sites (Bmax) were significantly higher in the follicular 
phase in untreated PMDD patients compared to controls. When treated with 
buserelin the difference disappeared. No differences in [3H]LSD binding between 
the three groups were shown. The present study demonstrated altered platelet 
[3H]paroxetine binding characteristics in women with PMDD compared to controls. 
Furthermore, [3H]paroxetine binding was affected by PMDD treatment with a low 
dose of buserelin. The results are consistent with the hypothesis that changes 
in serotonergic transmission could be a trait in the premenstrual dysphoric 
disorder.