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

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.

Conditions

• Smoking
• Nicotine Dependence
• Schizophrenia
• Schizophreniform Disorders
• Schizoaffective Disorder
• Psychosis

Interventions

DRUG

Nicotine patch

21 mg of nicotine via a dermal patch

OTHER

placebo

placebo via a dermal patch

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

Sponsors & Collaborators

• Canadian Psychiatric Research Foundation

  collaborator OTHER

• Centre for Addiction and Mental Health

  lead OTHER

Principal Investigators

• Jeff Daskalakis, MD, PhD · Centre for Addiction and Mental Health

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

60 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2007-02-28

Primary Completion

2008-08-31

Countries

• Canada

Study Locations