The role of glutamatergic dysfunction in treatment-resistant obsessive-compulsive disorder: treatment of an adolescent case with N-acetylcysteine augmentation

“N-Acetylcysteine for Obsessive-Compulsive and Related Disorders in Children and Adolescents: A Review”

Objective:

To evaluate clinical data using oral n-acetylcysteine (NAC) in obsessive-compulsive and related disorders (OCDRD) treatment.

Data Sources:

PubMed, Ovid MEDLINE (1946-July 2022), and the Cochrane Library database were searched using the terms NAC, children, adolescent, obsessive-compulsive disorder (OCD), trichotillomania (TTM), excoriation, hoarding disorder, and body dysmorphic disorder. Bibliographies were reviewed for relevant trials and case studies.

Study Selection and Data Extraction:

English language, clinical trials, or case studies analyzing NAC use in patients aged 3 to 21 years old with OCDRD as determined by the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition.

Data Synthesis:

Three randomized double-blind placebo-controlled trials of NAC in children and adolescents studied 121 patients with OCDRD. Trials assessed symptom severity from baseline to 10 to 12 weeks of NAC therapy. Two OCD trials identified statistically significant improvements, with only 1 trial demonstrating a clear clinically relevant difference from placebo. One trial in TTM found no difference between the NAC and placebo. Adverse effects were mild and included nausea, blurred vision, fatigue, tremor, and sweats. N-acetylcysteine titrated to 2400 or 2700 mg/day in divided doses was the most studied regimen.

Relevance to Patient Care and Clinical Practice:

Many OCDRD patients fail to completely respond to first-line treatment with cognitive behavioral therapy (CBT) and/or selective serotonin reuptake inhibitors (SSRIs) leaving practitioners with few additional treatment options. Preliminary efficacy and safety data are presented in this review.

Conclusions:

Limited evidence suggests children and adolescents with OCD refractory to SSRIs or CBT may benefit from NAC augmentation.

The Potential of N-Acetyl-L-Cysteine (NAC) in the Treatment of Psychiatric Disorders

N-acetyl-L-cysteine (NAC) is a compound of increasing interest in the treatment of psychiatric disorders. Primarily through its antioxidant, anti-inflammatory, and glutamate modulation activity, NAC has been investigated in the treatment of neurodevelopmental disorders, schizophrenia spectrum disorders, bipolar-related disorders, depressive disorders, anxiety disorders, obsessive compulsive-related disorders, substance-use disorders, neurocognitive disorders, and chronic pain. Whilst there is ample preclinical evidence and theoretical justification for the use of NAC in the treatment of multiple psychiatric disorders, clinical trials in most disorders have yielded mixed results. However, most studies have been underpowered and perhaps too brief, with some evidence of benefit only after months of treatment with NAC. Currently NAC has the most evidence of having a beneficial effect as an adjuvant agent in the negative symptoms of schizophrenia, severe autism, depression, and obsessive compulsive and related disorders. Future research with well-powered studies that are of sufficient length will be critical to better understand the utility of NAC in the treatment of psychiatric disorders.

N-acetylcysteine as a new prominent approach for treating psychiatric disorders

N-acetylcysteine (NAC) is a well-known and safe mucolytic agent, also used in patients with paracetamol overdose. In addition to these effects, recent preclinical and clinical studies have shown that NAC exerts beneficial effects on different psychiatric disorders. Many potential mechanisms have been proposed to underlie the therapeutic effects of NAC, including the regulation of several neurotransmitters, oxidative homeostasis, and inflammatory mediators. In this paper, we summarize the current knowledge on the ability of NAC to ameliorate symptoms and neuropathologies related to different psychiatric disorders, including attention deficit hyperactivity disorder, anxiety, bipolar disorder, depression, obsessive-compulsive disorder, obsessive-compulsive-related disorder, posttraumatic stress disorder, and schizophrenia. Although preclinical studies have shown a positive effect of NAC on animal models of psychiatric disorders, the clinical efficacy of NAC is not fully established. NAC remains a strong candidate for adjunct treatment for many psychiatric disorders, but additional preclinical and clinical studies are needed.

Oral N-acetylcysteine in the treatment of obsessive-compulsive disorder: A systematic review of the clinical evidence

Obsessive-compulsive disorder (OCD) is characterized by the presence of obsessions and/or compulsions. It is a leading cause of morbidity worldwide, as it can interfere with all aspects of life. Despite the adequate treatment trials, half of patients preserve residual or impairing symptoms and selective serotonin reuptake inhibitors (SSRIs) are not free from adverse side effects. This work aims to systematically review the current evidence available concerning the efficacy of N-acetylcysteine (NAC) in the treatment of OCD. Five randomized placebo-controlled trials (RCTs), 3 case reports and 2 case series were included. The studies developed so far are somehow contradictory. However, our pooled result from the 4 observational studies (n = 13) showed a mean reduction in Y-BOCS score after NAC treatment of -11 points (p = .01). Pooled mean difference from 4 of the 5 RCTs included was 3.35, with a95% confidence interval of -0.21-6.91 and a p-value barely below statistical significance (p = .07). This result trends to favour the use of NAC over placebo in OCD patients. NAC has an optimal tolerability profile, even in higher doses, and the most frequently reported adverse events were gastrointestinal. Despite the degree of evidence being D, in our opinion the potential of NAC is underestimated. Considering its exceptional tolerability profile, the use as an add-on agent should be contemplated, on an ad hoc basis.

N-acetylcysteine in the treatment of psychiatric disorders: current status and future prospects

INTRODUCTION

N-acetylcysteine (NAC) is widely known for its role as a mucolytic and as an antidote to paracetamol overdose. There is increasing interest in the use of NAC in the treatment of several psychiatric disorders. The rationale for the administration of NAC in psychiatric conditions is based on its role as a precursor to the antioxidant glutathione, and its action as a modulating agent of glutamatergic, dopaminergic, neurotropic and inflammatory pathways. Areas covered: This study reviews the available data regarding the use of NAC in different psychiatric disorders including substance use disorders, autism, obsessive-compulsive spectrum disorders, schizophrenia, depression, bipolar disorder. Promising results were found in trials testing the use of NAC, mainly as an add-on treatment, in cannabis use disorder in young people, depression in bipolar disorder, negative symptoms in schizophrenia, and excoriation (skin-picking) disorder. Despite initial optimism, recent findings regarding NAC efficacy in autism have been disappointing. Expert opinion: These preliminary positive results require further confirmation in larger samples and with longer follow-ups. Given its high tolerability and wide availability, NAC represents an important target to investigate in the field of new adjunctive treatments for psychiatric conditions.