Acute hormonal changes after IV citalopram and treatment response in OCD

Serotonergic pharmacological challenges have failed to produce consensual results in patients with obsessive-compulsive disorder (OCD), suggesting a heterogeneous 5-hydroxytryptamine (5-HT) activity in this disorder.

The aim of this study was to compare the neuroendocrine response to a serotonergic challenge in OCD patient responders (RP) and nonresponders (NR) to serotonin reuptake inhibitors treatment and healthy volunteers.

Thirty OCD treatment NR, 30 RP, and 30 controls (CN) matched for sex and age were included. Each subject received 20 mg of intravenous citalopram. Prolactin, cortisol, and growth hormone plasma concentration were measured at times-20, 0, 20, 40, 60, 80, 100, 120, 140, and 160 min after the onset of citalopram infusion.

Citalopram did not induce anxiety or OCD symptoms in patients. Citalopram was associated with stronger prolactin response in the CN group (maximal percentage variation [max%Delta] = 65.76 +/- 105.1) than in NR (max%Delta = 17.41 +/- 31.06) and RP groups (max%Delta = 15.87 +/- 31.71; p = 0.032; Friedman chi (2) = 6.87; df = 2). On the other hand, cortisol response did not differ between CN and RP groups and was blunted in the NR group (NR max%Delta = 20.98 +/- 58.14 vs RP max%Delta = 47.69 +/- 66.94; CN max%Delta = 63.58 +/- 88.4; p = 0.015; Friedman chi (2) = 8.60; df = 2).

Compared to CN, both treatment RP and NR patients showed blunted prolactin response to citalopram, but only NR patients showed an attenuated cortisol response, suggesting a more disrupted central serotonergic transmission in this group.