Pediatric Obsessive-Compulsive Disorder (OCD) affects 1-3% of children. The investigators currently have effective first-line interventions for pediatric OCD such as Cognitive Behavioral Therapy (CBT) and pharmacotherapy with serotonin reuptake inhibitors (SRIs). However, roughly half of children with OCD still have clinically significant OCD symptoms despite treatment with first-line pharmacological treatments and CBT interventions for OCD. Furthermore, all pharmacological treatments for OCD in children have an increased side effect burden when compared to adults. Novel treatments for children with OCD are needed.

N-acetylcysteine (NAC) is a natural supplement that acts as an antioxidant and a glutamate modulating agent. NAC has been used safely for decades in doses 20-40 times higher than in this trial as an antidote for acetaminophen overdose. The only side-effect commonly seen with NAC is nausea and this side-effect is seldom seen in the doses used in this trial.

NAC has recently been demonstrated to be effective in a double-blind, placebo-controlled trial in adults with trichotillomania (chronic hair pulling). Trichotillomania is an obsessive-compulsive spectrum disorder that is hypothesized to be closely related to OCD. In other trials NAC has evidence of some efficacy in treating diverse psychiatric conditions such as bipolar depression, schizophrenia and cocaine dependence.

The investigators are conducting this trial to determine if NAC is effective in treating OCD.

Pediatric Obsessive-Compulsive Disorder (OCD) affects 1-3% of children. The investigators currently have effective first-line interventions for pediatric OCD such as Cognitive Behavioral Therapy (CBT) and pharmacotherapy with serotonin reuptake inhibitors (SRIs). However, roughly half of children with OCD still have clinically significant OCD symptoms despite treatment with first-line pharmacological treatments and CBT interventions for OCD. Furthermore, all pharmacological treatments for OCD in children have an increased side effect burden when compared to adults. Novel treatments for children with OCD are needed.

N-acetylcysteine (NAC) is a natural supplement that acts as an antioxidant and a glutamate modulating agent. NAC has been used safely for decades in doses 20-40 times higher than in this trial as an antidote for acetaminophen overdose. The only side-effect commonly seen with NAC is nausea and this side-effect is seldom seen in the doses used in this trial.

NAC has recently been demonstrated to be effective in a double-blind, placebo-controlled trial in adults with trichotillomania (chronic hair pulling). Trichotillomania is an obsessive-compulsive spectrum disorder that is hypothesized to be closely related to OCD. In other trials NAC has evidence of some efficacy in treating diverse psychiatric conditions such as bipolar depression, schizophrenia and cocaine dependence.

The investigators are conducting this trial to determine if NAC is effective in treating OCD.