N-Acetylcysteine for Pediatric Obsessive-Compulsive Disorder: A Small Pilot Study

Abstract

Background: Many children and adults with Obsessive-Compulsive Disorder (OCD) fail to respond to first-line pharmacological and behavioral treatments. Glutamate dysfunction may contribute to the development of OCD. N-acetylcysteine (NAC), a glutamate modulating drug, has shown to be a promising agent in adults with OCD. Methods: We conducted a double-blind, placebo-controlled clinical trial from July 2012 to January 2017. Children ages 8 to 17 years with OCD were assigned to receive NAC (up to 2700 mg/day) or the matching placebo for a period of 12 weeks. Children were required to be on stable psychiatric treatment (both medication and therapy) but were not required to be treatment-refractory. The primary outcome was OCD symptom severity as measured by the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS). We used linear mixed models to analyze the effect of NAC compared to placebo. Results: Due to poor recruitment and eventual expiration of the study medication, enrollment was stopped at 11 children out of a planned sample size of 40. Nonetheless, NAC was associated with significant reduction in CY-BOCS total score compared to placebo (Satterthwaite's test: t (37) = 2.36, p = 0.024) with effects separating from placebo beginning at week 8. Mean CY-BOCS total score decreased in the NAC group from 21.4 ± 4.65 at baseline to 14.4 ± 5.55 at week 12. In the placebo group, mean CY-BOCS total score remained unchanged (21.3 ± 4.65). In the NAC group, 1 out of 5 participants achieved >35% improvement in CY-BOCS total score, while none of the six patients in placebo group reached this improvement level. NAC and placebo were well tolerated. One mild adverse event was reported in each group. Conclusions: Our trial suggests that there may be some initial improvement in OCD symptom severity with NAC treatment. NAC was well tolerated in the study population. Future trials should employ multiple sites and have a larger study population to further confirm any benefits of NAC.

Keywords: N-acetylcysteine; adolescence; child; obsessive-compulsive disorder; randomized controlled trial.

FIG. 1.

CONSORT diagram. NAC, N-acetylcysteine.

FIG. 2.

Effects of NAC and placebo on OCD Severity. OCD severity was measured with the CY-BOCS. (A) Depicts the mean CY-BOCS ratings over time for both the NAC and placebo groups and (B) depicts CY-BOCS ratings for individual subjects in the trial. (B) Trajectories with solid lines and markers represent subjects receiving NAC and trajectories with dashed lines and nonfilled markers represent subjects receiving placebo. *p < 0.05. CY-BOCS, Children's Yale-Brown Obsessive-Compulsive Scale; NAC, N-acetylcysteine.