Fenfluramine challenge test in obsessive-compulsive disorder--first results

Area of Science:

• Psychiatry
• Neuroscience
• Pharmacology

Background:

• Obsessive-compulsive disorder (OCD) is a chronic illness affecting up to 3% of the population.
• Historically considered untreatable, pharmacotherapy is now a viable option.
• Serotoninergic antidepressants are a key treatment modality for OCD.

Purpose of the Study:

• To compare the efficacy and safety of citalopram versus clomipramine in treating OCD over six weeks.
• To assess the impact of this treatment on prolactin response to a fenfluramine challenge test.
• To explore potential differences in the biological background of obsessions and compulsions.

Main Methods:

• A 6-week double-blind study comparing citalopram and clomipramine in 14 OCD patients.
• Inclusion of a fenfluramine challenge test to measure prolactin levels before and after treatment.
• Utilized the Yale-Brown Obsessive Compulsive Scale (YBOCS) to assess symptom severity.

Main Results:

• Significant therapeutic response observed after three weeks, with greater improvement in obsessions than compulsions.
• Low incidence of adverse effects including dry mouth, anxiety, nausea, somnolence, tremor, and sexual dysfunction.
• Fenfluramine challenge test revealed a significant decrease in prolactin levels one hour post-administration before treatment, which was not observed after six weeks.
• A negative correlation was found between prolactin levels and obsession severity on the YBOCS after three and six weeks of treatment.

Conclusions:

• Pharmacotherapy with citalopram or clomipramine demonstrates efficacy in treating OCD symptoms.
• The fenfluramine challenge test may offer insights into the neurobiological mechanisms underlying OCD.
• Obsessions and compulsions might have different biological bases, warranting further investigation.