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Neural Inhibition as a Mechanism of Nicotine Dependence Among Persons With Schizophrenia

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00407277
Recruitment Status : Completed
First Posted : December 4, 2006
Last Update Posted : March 18, 2009
Canadian Psychiatric Research Foundation
Information provided by:
Centre for Addiction and Mental Health

Brief Summary:
Cigarette smoking decreases life expectancy, causes devastating health complications, and costs society billions of dollars each year. These untoward consequences are especially pronounced among persons with schizophrenia (SCZ) because approximately 80% to 95% of this group smokes cigarettes. These high prevalence rates underscore the need for research investigating the determinants of smoking in patients with SCZ. Several researchers have observed that nicotine improves specific symptoms of SCZ including negative symptoms, negative affect, and cognitive deficits. This has led to the hypothesis that patients with SCZ smoke in an attempt to self-medicate. However, the mechanism(s) by which nicotine has its positive effect on symptoms remains unclear. The current proposal posits that neural inhibition (NI) is a physiological mechanism of this effect, while variation in the alpha-7-nicotinic receptor subunit gene (CHRNA7) represents the genetic underpinnings of these processes. The proposed study will assess NI and symptom improvement after acute administration of nicotine to both smokers and nonsmokers with SCZ. In addition, NI and CHRNA7 variation will be tested as predictors of patients' ability to reduce/quit smoking following smoking treatment. These data may lead to the development of new pharmacological strategies for treating the symptoms of SCZ and new methods for assisting these patients to quit smoking.

Condition or disease Intervention/treatment Phase
Smoking Nicotine Dependence Schizophrenia Schizophreniform Disorders Schizoaffective Disorder Psychosis Drug: Nicotine patch Other: placebo Behavioral: smoking cessation group therapy Not Applicable

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 120 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary Purpose: Basic Science
Official Title: Neural Inhibition as a Mechanism of Nicotine Dependence Among Persons With Schizophrenia
Study Start Date : February 2007
Actual Primary Completion Date : August 2008

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Schizophrenia

Arm Intervention/treatment
Experimental: 1A Drug: Nicotine patch
21 mg of nicotine via a dermal patch

Placebo Comparator: 1B Other: placebo
placebo via a dermal patch

Experimental: 2A Behavioral: smoking cessation group therapy
a 9-week group based on the "Freedom From Smoking" program designed by the American Lung Association. The treatment was manualized and modified to meet the functional and cognitive capabilities of patients with psychotic disorders

Primary Outcome Measures :
  1. neural inhibition via EEG and TMS [ Time Frame: intermittent ]

Secondary Outcome Measures :
  1. Self reported tobacco use [ Time Frame: intermittent ]
  2. Polymorphic markers in the CHRNA7 gene and promoter region [ Time Frame: baseline ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Voluntary and competent to consent
  • Have a diagnosis of schizophrenia, schizophreniform, or schizoaffective disorder as confirmed by the Structured Clinical Interview for the DSM-IV (SCID-IV)
  • Between the ages of 18 and 60

Exclusion Criteria:

  • Have a DSM-IV history of substance abuse or dependence (other than caffeine or nicotine) in the last 6 months
  • Have a self-reported concomitant major medical or neurologic illness
  • Pregnant
  • Currently prescribed medications known to deleteriously affect cognition (e.g., benzodiazepines, tricyclic anti-depressants, anticholinergics, MAO inhibitors, GABA-B agonists)
  • Currently taking clozapine (due to its documented effect on both NI and smoking
  • Report suffering from conditions that may be aggravated by acute nicotine administration (e.g., arrhythmias, recent myocardial infarction)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00407277

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Canada, Ontario
Centre for Addiction and Mental Health
Toronto, Ontario, Canada, M5T 1R8
Sponsors and Collaborators
Centre for Addiction and Mental Health
Canadian Psychiatric Research Foundation
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Principal Investigator: Jeff Daskalakis, MD, PhD Centre for Addiction and Mental Health

Additional Information:
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Responsible Party: Dr. Jeff Daskalakis, Centre for Addiction and Mental Health Identifier: NCT00407277     History of Changes
Other Study ID Numbers: 63/2005
First Posted: December 4, 2006    Key Record Dates
Last Update Posted: March 18, 2009
Last Verified: March 2009

Keywords provided by Centre for Addiction and Mental Health:
nicotine dependence
nicotine patch
schizoaffective disorder

Additional relevant MeSH terms:
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Psychotic Disorders
Mental Disorders
Tobacco Use Disorder
Pathologic Processes
Schizophrenia Spectrum and Other Psychotic Disorders
Substance-Related Disorders
Chemically-Induced Disorders
Ganglionic Stimulants
Autonomic Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Nicotinic Agonists
Cholinergic Agonists
Cholinergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action