N-acetylcysteine augmentation in serotonin reuptake inhibitor refractory obsessive-compulsive disorder

Rationale: Dysfunction of glutamatergic neurotransmission has been implicated in the pathophysiology of obsessive-compulsive disorder (OCD) and recent clinical reports suggest that some glutamate modulating agents are efficacious in the treatment of this disorder. N-acetylcysteine (NAC) is a readily available amino acid compound that is thought to attenuate glutamatergic neurotransmission. NAC may be useful in treating psychiatric disorders involving glutamatergic dysfunction such as OCD. Objectives: To examine the efficacy of augmentation with NAC in a patient with serotonin reuptake inhibitor (SRI)-refractory OCD. Methods: A patient with SRI-refractory OCD was treated with an off-label use of NAC augmentation of fluvoxamine over several weeks. Results: NAC augmentation of fluvoxamine resulted in a marked decrease in Yale-Brown Obsessive Compulsive Scale (Y-BBOCS) score and a clinically significant improvement in OCD symptoms. Conclusions: NAC augmentation was effective in treating SRI-refractory OCD in this single case. Further research is warranted to investigate the use of NAC and other glutamate modulating agents in the treatment of OCD.