Augmentation therapy of N-acetylcysteine for OCD: A meta-analysis of double-blind, randomized, placebo-controlled trials

Treatment resistance is a barrier to the successful care of patients with OCD. Glutamate modulators such as n-acetylcysteine (NAC) represent a promising new treatment option. To elucidate the current evidence of the efficacy and safety of NAC, we performed a systematic review and meta-analysis of double-blind, randomized, placebo-controlled trials. Primary outcomes were full and partial response rates and a reduction in the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Improvement in other clinical scales and the prevalence of various adverse events were also analyzed. Five RCTs (a total of 102 NAC and 100 placebo participants) were found eligible for inclusion. No significant differences in full responses (RR = 1.60; 95% CI = 0.37–6.95, Z = 0.63; p = 0.53), in partial responses (RR = 1.24; 95% CI = 0.76–2.03, Z = 0.85; p = 0.39), and in the reduction in the Y-BOCS (SMD = −0.66; 95% CI = −1.50 – 0.17, Z = 1.56; p = 0.12) were observed between the groups. In general, NAC was well tolerated and no significant differences in the prevalence of adverse events were found between the groups. The current evidence that NAC augmentation is an effective option for treatment resistant OCD is limited.