Neural Inhibition as a Mechanism of Nicotine Dependence Among Persons With Schizophrenia
1 other identifier
interventional
120
1 country
1
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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P50-P75 for not_applicable
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
November 30, 2006
CompletedFirst Posted
Study publicly available on registry
December 4, 2006
CompletedStudy Start
First participant enrolled
February 1, 2007
CompletedPrimary Completion
Last participant's last visit for primary outcome
August 1, 2008
CompletedMarch 18, 2009
March 1, 2009
1.5 years
November 30, 2006
March 17, 2009
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
neural inhibition via EEG and TMS
intermittent
Secondary Outcomes (2)
Self reported tobacco use
intermittent
Polymorphic markers in the CHRNA7 gene and promoter region
baseline
Study Arms (3)
1A
EXPERIMENTAL1B
PLACEBO COMPARATOR2A
EXPERIMENTALInterventions
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
Eligibility Criteria
You may qualify if:
- 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
You may not qualify if:
- 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)
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Centre for Addiction and Mental Health
Toronto, Ontario, M5T 1R8, Canada
Related Publications (6)
Addington J, el-Guebaly N. Group treatment for substance abuse in schizophrenia. Can J Psychiatry. 1998 Oct;43(8):843-5. doi: 10.1177/070674379804300810.
PMID: 9806092BACKGROUNDAddington J, el-Guebaly N, Campbell W, Hodgins DC, Addington D. Smoking cessation treatment for patients with schizophrenia. Am J Psychiatry. 1998 Jul;155(7):974-6. doi: 10.1176/ajp.155.7.974.
PMID: 9659869BACKGROUNDAddington D, Addington J, Maticka-Tyndale E. Assessing depression in schizophrenia: the Calgary Depression Scale. Br J Psychiatry Suppl. 1993 Dec;(22):39-44.
PMID: 8110442BACKGROUNDAdler LE, Olincy A, Waldo M, Harris JG, Griffith J, Stevens K, Flach K, Nagamoto H, Bickford P, Leonard S, Freedman R. Schizophrenia, sensory gating, and nicotinic receptors. Schizophr Bull. 1998;24(2):189-202. doi: 10.1093/oxfordjournals.schbul.a033320.
PMID: 9613620BACKGROUNDBaron RM, Kenny DA. The moderator-mediator variable distinction in social psychological research: conceptual, strategic, and statistical considerations. J Pers Soc Psychol. 1986 Dec;51(6):1173-82. doi: 10.1037//0022-3514.51.6.1173.
PMID: 3806354BACKGROUNDBohadana A, Nilsson F, Rasmussen T, Martinet Y. Nicotine inhaler and nicotine patch as a combination therapy for smoking cessation: a randomized, double-blind, placebo-controlled trial. Arch Intern Med. 2000 Nov 13;160(20):3128-34. doi: 10.1001/archinte.160.20.3128.
PMID: 11074742BACKGROUND
Related Links
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Study Officials
- PRINCIPAL INVESTIGATOR
Jeff Daskalakis, MD, PhD
Centre for Addiction and Mental Health
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- TRIPLE
- Who Masked
- PARTICIPANT, CARE PROVIDER, INVESTIGATOR
- Purpose
- BASIC SCIENCE
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
Study Record Dates
First Submitted
November 30, 2006
First Posted
December 4, 2006
Study Start
February 1, 2007
Primary Completion
August 1, 2008
Last Updated
March 18, 2009
Record last verified: 2009-03