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A Study of N-Acetyl Cysteine in Children With Autism

This study has been completed.
Information provided by (Responsible Party):
Antonio Hardan, Stanford University Identifier:
First received: February 22, 2008
Last updated: April 10, 2017
Last verified: April 2017

The purpose of the study is to test the tolerability and efficacy of N-Acetyl Cysteine (NAC) in children with Autism. NAC is a compound that increases the levels of Glutathione, the body's main antioxidant. Glutathione is a compound in the blood that is part of a natural defense system (the antioxidant system). Anti-oxidants protect the body from damage caused by internal toxins called "free radicals." It is possible that children with Autism tend to have lower levels of glutathione, an important compound in our bodies that helps combat the effects of toxic free radicals.

We hope that by studying the antioxidant system in more detail, we will increase our understanding of the reasons why people develop Autism so that we can design better ways to treat individuals with this condition. This study is meant to test the safety tolerability of NAC and its effectiveness in the treatment of behavioral difficulties in children with autism. It will also examine the possible benefit of this agent in improving the core deficits in autism such as social deficits.

Condition Intervention Phase
Autistic Disorder Drug: N-Acetyl Cysteine Other: Placebo - sugar pill Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Double-blind , Randomized, Placebo Controlled Study of N-Acetyl Cysteine in Autism.

Resource links provided by NLM:

Further study details as provided by Antonio Hardan, Stanford University:

Primary Outcome Measures:
  • Total Number of Subjects With Reported Side Effects as Assessed by Dosage Record and Treatment Emergent Symptom Scale (DOTES) [ Time Frame: 4, 8, and 12 weeks ]
    The Dosage Record and Treatment Emergent Symptom Scale (DOTES) provides information on the presence, frequency, and severity of side effects reported during the course of the trial.

  • The Clinical Global Rating Scale (CGRS) Improvement Subscale Score [ Time Frame: 12 weeks ]
    Score range 1-7 (lower score mean more improvement compared to baseline)

  • Glutathione (GSH) Levels in Peripheral Blood, Measured by State-of-the-art High-performance Liquid Chromatography (HPLC) [ Time Frame: 12 weeks ]
    Data not collected. The laboratory was not able to measure Glutathione levels.

  • Irritability Subscale of the Aberrant Behavior Checklist (ABC) [ Time Frame: baseline and 12 weeks ]
    Aberrant Behavior Checklist (ABC) Irritability Subscale Score (range 0-45); higher scores mean higher irritability

Secondary Outcome Measures:
  • The Aberrant Behavior Checklist Total Score (ABC) [ Time Frame: 4, 8, and 12 weeks ]
    Total score was not analyzed since we analyzed the sub scales. Additionally, the authors of the instrument do not recommend analyzing the total score.

  • Social Responsiveness Scale (SRS) [ Time Frame: 12 weeks ]
    SRS total score (range 0-195); higher scores mean more social impairment

  • Sensory Profile Questionnaire (SPQ) [ Time Frame: 12 weeks ]
  • Glutathione (GSH) Metabolism Intermediates in Peripheral Blood [ Time Frame: 12 weeks ]

Enrollment: 43
Study Start Date: February 2008
Study Completion Date: September 2010
Primary Completion Date: September 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: N-Acetyl Cysteine
active compound N-Acetyl Cysteine
Drug: N-Acetyl Cysteine

Phase 1: Oral, 900 mg daily for 4 weeks Phase 2: Oral, 900 mg twice daily 4 weeks Phase 3: Oral, 900 mg three times daily for 4 weeks

Entire intervention lasts for 12 weeks (drug administration is continuous).

Other Name: NAC
Placebo Comparator: Sugar pill
Placebo or sugar pill
Other: Placebo - sugar pill

Phase 1: Oral, 900 mg daily for 4 weeks Phase 2: Oral, 900 mg twice daily 4 weeks Phase 3: Oral, 900 mg three times daily for 4 weeks

Entire intervention lasts for 12 weeks (drug administration is continuous).

Other Name: Placebo


Ages Eligible for Study:   3 Years to 12 Years   (Child)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Outpatients between 3.0 and 12.11 years of age inclusive
  2. Males and females who are physically healthy
  3. diagnosis of autism based Diagnostic and Statistical Manual (DSM-IV-TR) criteria, the Autism Diagnostic Interview-Revised, and expert clinical evaluation
  4. Clinical Global Impression Severity rating of 4
  5. Care provider who can reliably bring subject to clinic visits, can provide trustworthy ratings, and interacts with subject on a regular basis
  6. Ability of subject to swallow the compound
  7. Stable concomitant medications for at least 2 weeks
  8. No planned changes in psychosocial interventions during the open-label N-Acetyl Cysteine trial

Exclusion Criteria:

  1. DSM-IV-TR diagnosis of schizophrenia, schizoaffective disorder, or psychotic disorder not otherwise specified
  2. Prior adequate trial of N-Acetyl Cysteine
  3. Active medical problems: unstable seizures, significant physical illness (e.g., serious liver or renal pathology)
  4. Pregnancy or sexually active females
  5. Subjects taking antioxidant agents and glutathione prodrugs will be excluded from the study except if they have been off these compounds for at least 4 weeks
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00627705

United States, California
Stanford University School of Medicine
Stanford, California, United States, 94305
Sponsors and Collaborators
Stanford University
Principal Investigator: Antonio Hardan, MD Stanford University
  More Information

Responsible Party: Antonio Hardan, Professor, Stanford University Identifier: NCT00627705     History of Changes
Other Study ID Numbers: SU-02012008-995
Study First Received: February 22, 2008
Results First Received: August 12, 2016
Last Updated: April 10, 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes

Additional relevant MeSH terms:
Autistic Disorder
Child Development Disorders, Pervasive
Neurodevelopmental Disorders
Mental Disorders
Antiviral Agents
Anti-Infective Agents
Respiratory System Agents
Free Radical Scavengers
Molecular Mechanisms of Pharmacological Action
Protective Agents
Physiological Effects of Drugs
Antidotes processed this record on September 19, 2017