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N-acetylcysteine (NAC) for Children With Tourette Syndrome

Information source: Yale University
ClinicalTrials.gov processed this data on August 23, 2015
Link to the current ClinicalTrials.gov record.

Condition(s) targeted: Tourettes Syndrome; Tic

Intervention: N-Acetylcysteine (NAC) (Drug); Placebo (Drug)

Phase: Phase 2

Status: Completed

Sponsored by: Yale University

Official(s) and/or principal investigator(s):
Michael H. Bloch, MD, MS, Principal Investigator, Affiliation: Yale University


Tourette syndrome is a childhood-onset neuropsychiatric disorder characterized by multiple motor and vocal tics that last for at least a year in duration. Currently, there exist several effective pharmacological treatments for childhood tics including alpha-2 agonist medications (guanfacine and clonidine) and neuroleptics (antipsychotic) medications. These medications, however, have significant side-effects and are only partially efficacy in treating tics. N-acetylcysteine (NAC) is a natural supplement that acts as an antioxidant and 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). Hairpulling is hypothesized to be closely related to tics because these conditions (1) have similar clinical

characteristics - - both groups typically experience urges before engaging in pulling or

tics, (2) neuroimaging studies suggest they involve similar brain circuits - - the basal

ganglia, (3) the same pharmacological treatments (neuroleptics) may be effective for both conditions and (4) they tend to be inherited together in families. 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 an effective treatment for tics.

Clinical Details

Official title: Double-Blind, Placebo-Controlled Trial of N-acetylcysteine (NAC) for the Treatment of Children With Tourette Syndrome

Study design: Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Treatment

Primary outcome: Improvement in Tic Severity

Secondary outcome:

Improvement of Premonitory Urges

Improvement in OCD Severity

Overall Improvement

Adverse Effects


Minimum age: 8 Years. Maximum age: 17 Years. Gender(s): Both.


Inclusion Criteria:

- Children aged 8-17 years.

- Primary diagnosis of Tourette syndrome or chronic tic disorder.

- Duration of tics greater than 1 year.

- Significant Current tic symptoms: Current YGTSS score greater than or equal to 22

with a TS diagnosis or greater than or equal to 14 with a chronic tic disorder. Exclusion Criteria:

- Comorbid bipolar disorder, psychotic disorder, substance use disorder, developmental

disorder or mental retardation (IQ<70).

- Recent change (less than 4 weeks) in medications that have potential effects on tic

severity (such as neuroleptic medications, dopamine agonists, alpha-2 agonists (guanfacine, clonidine or prazosin), SSRIs, clomipramine, naltrexone, lithium, psychostimulants, or anxiolytics). Medication change is defined to include dose changes or medication discontinuation.

- Recent change in behavioral treatment for Tourette syndrome or comorbid conditions

(i. e. OCD) within the last 4 weeks or initiation of behavioral therapy for tics within the last 12 weeks.

- Asthma requiring medication use within the last 3 months

- Known hypersensitivity or previous anaphylactoid reaction to acetylcysteine or any

components in its preparation

- Positive pregnancy test or drug screening test.

- Previous use of N-acetylcysteine (dose greater than 600mg for more than 2 weeks)

Locations and Contacts

Yale Child Study Center, New Haven, Connecticut 06520, United States
Additional Information

Related publications:

Grant JE, Odlaug BL, Kim SW. N-acetylcysteine, a glutamate modulator, in the treatment of trichotillomania: a double-blind, placebo-controlled study. Arch Gen Psychiatry. 2009 Jul;66(7):756-63. doi: 10.1001/archgenpsychiatry.2009.60.

Bloch MH, Leckman JF. Clinical course of Tourette syndrome. J Psychosom Res. 2009 Dec;67(6):497-501. doi: 10.1016/j.jpsychores.2009.09.002. Review.

Berk M, Copolov DL, Dean O, Lu K, Jeavons S, Schapkaitz I, Anderson-Hunt M, Bush AI. N-acetyl cysteine for depressive symptoms in bipolar disorder--a double-blind randomized placebo-controlled trial. Biol Psychiatry. 2008 Sep 15;64(6):468-75. doi: 10.1016/j.biopsych.2008.04.022. Epub 2008 Jun 5.

Berk M, Copolov D, Dean O, Lu K, Jeavons S, Schapkaitz I, Anderson-Hunt M, Judd F, Katz F, Katz P, Ording-Jespersen S, Little J, Conus P, Cuenod M, Do KQ, Bush AI. N-acetyl cysteine as a glutathione precursor for schizophrenia--a double-blind, randomized, placebo-controlled trial. Biol Psychiatry. 2008 Sep 1;64(5):361-8. doi: 10.1016/j.biopsych.2008.03.004. Epub 2008 Apr 23.

Ng F, Berk M, Dean O, Bush AI. Oxidative stress in psychiatric disorders: evidence base and therapeutic implications. Int J Neuropsychopharmacol. 2008 Sep;11(6):851-76. doi: 10.1017/S1461145707008401. Epub 2008 Jan 21. Review.

Singer HS, Morris C, Grados M. Glutamatergic modulatory therapy for Tourette syndrome. Med Hypotheses. 2010 May;74(5):862-7. doi: 10.1016/j.mehy.2009.11.028. Epub 2009 Dec 21.

Starting date: July 2010
Last updated: July 21, 2014

Page last updated: August 23, 2015

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