Changes in cerebrospinal fluid neurochemistry during treatment of obsessive-compulsive disorder with clomipramine.

Background: This study examined the effect of long-term (mean, 19 months) treatment with clomipramine hydrochloride on cerebrospinal fluid (CSF) levels of several neuropeptides and monoamine metabolites in children and adolescents with obsessive-compulsive disorder.

Methods: The CSF levels of corticotropin-releasing hormone, vasopressin, somatostatin, and oxytocin and of the monoamine metabolites 5-hydroxyindoleacetic acid, homovanillic acid, and 3-methoxy-4-hydroxyphenylglycol were measured in 17 children and adolescents with obsessive-compulsive disorder before and after long-term treatment with clomipramine.

Results: Treatment resulted in significant decreases in CSF levels of corticotropin-releasing hormone (mean +/- SD, 175 +/- 32 vs 152 +/- 25 pmol/L, P < .03) and vasopressin (mean +/- SD, 1.30 +/- 0.57 vs 0.86 +/- 0.54 pmol/L, P < .02) and a trend toward a decrease in somatostatin levels (mean +/- SD, 21.3 +/- 8.5 vs 15.3 +/- 9.8 pmol/L, P < .06). Treatment also significantly increased CSF oxytocin levels (mean +/- SD, 6.05 +/- 1.60 vs 6.70 +/- 1.44 pmol/L, P < .01). Significant changes in CSF monoamine metabolite levels with treatment included significant decreases in CSF levels of 5-hydroxyindoleacetic acid (mean +/- SD, 109 +/- 31 vs 77 +/- 23 pmol/mL, P < .001), CSF homovanillic acid (mean +/- SD, 273 +/- 111 vs 237 +/- 101 pmol/mL, P < .04), and 3-methoxy-4-hydroxyphenylglycol (mean +/- SD, 42.4 +/- 10.2 vs 36.1 +/- 4.8 pmol/L, P < .02) and a significant increase in the homovanillic acid-5-hydroxyindoleacetic acid ratio (mean +/- SD, 2.44 +/- 0.46 vs 3.42 +/- 0.84, P < .0001).

Conclusions: These neuropeptide results coupled with evidence that central administration of corticotropin-releasing hormone, vasopressin, and somatostatin to laboratory animals increases arousal and acquisition of conditioned behaviors whereas central administration of oxytocin has opposite behavioral effects are consistent with a role for these neuropeptides in the pathophysiologic processes and pharmacologic treatment of obsessive-compulsive disorder.