Skip to main content
OpenTrials
Completed

NCT Number: NCT04001114

Cigarette Smoking in Smokers With and Without Schizophrenia

Higher rates and severity of tobacco dependence in people with schizophrenia, as compared with the general population, contribute to the lower life expectancy seen in this population. Dependent tobacco smoking is controlled by how different aspects of cigarette smoking are perceived. There is evidence suggesting that people with schizophrenia differ in how they perceive cigarette smoking, which, if confirmed, would have implications for tailoring treatment interventions for smoking cessation in schizophrenia.

Completed

Looking for future studies?

Notify Me

Key information

Conditions

Tobacco Dependence Chemically-Induced Disorders Mental Disorders Schizophrenia Schizophrenia Spectrum and Other Psychotic Disorders Substance-Related Disorders Tobacco Use Disorder

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Maryland Psychiatric Research Center

Catonsville, Maryland, 21228, United States

About this study

The aim of the present study is to determine whether tobacco smoking in people with schizophrenia is governed by different aspects and effects of cigarette consumption. Smokers participating in this study either have no psychiatric diagnosis, or a diagnosis of schizophrenia or schizoaffective disorder. Over four study visits, participants will sample and compare different research cigarettes, complete questionnaires and concentration tasks, and smoke one type of research cigarette for eight hours while wearing a nicotine patch. By shaping our understanding of tobacco dependence in schizophrenia, the present project may redirect treatment development toward strategies tailored to the specific vulnerabilities of this population, which is among the most severely affected by its detrimental impact on health and life.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Regular smoker of at least 10 cigarettes or cigarillos/day for at least 2 years
  • For participants with schizophrenia: DSM-5 diagnosis of schizophrenia or schizoaffective disorder
  • For participants with schizophrenia: Able to give informed consent
  • For smokers with schizophrenia: No change in psychiatric medication or dosage in the last 4 weeks

Exclusion criteria

  • Uncontrolled hypertension (resting systolic BP above 150 or diastolic above 95 mm Hg)
  • Cardiovascular disease, such as history of myocardial infarction and ischemia, heart failure, angina, severe arrhythmias, or EKG abnormalities
  • Severe asthma
  • Chronic obstructive pulmonary disease
  • Neurological illness, such as stroke, seizure disorder, neurodegenerative disease, or organic brain syndrome
  • Mental retardation
  • Alcohol or substance use disorder except nicotine within the last year
  • Use of benztropine (Cogentin), varenicline (Chantix), bupropion (Wellbutrin, Zyban), or any type of nicotine replacement
  • Pregnant or lactating
  • For healthy control smokers: DSM-5 diagnosis of depression, bipolar disorder, ADHD, autism spectrum disorder, anorexia, bulimia nervosa, or any schizophrenia-spectrum disorder
  • For healthy control smokers: immediate family history of psychosis

Treatment and study plan

Sampling Research Cigarettes

Combination Product

Participants sample two research cigarettes, which differ in typical tobacco smoke constituents such as tar, nicotine, carbon monoxide, etc. In the Cigarette Discrimination Session, participants sample both types of cigarettes repeatedly, guess their identity (A or B) with regard to reference cigarettes, and rate their subjective effects. In the Ad Libitum Smoking Session, participants can smoke one of these cigarette types as much or as little as they like for eight hours.

Primary outcomes

  1. End-of-session Carbon Monoxide

    Time frame: One day (in the Ad Libitum Smoking Session), over an 8-hour time frame.

    The concentration (ppm) of carbon monoxide (CO) in breath is measured by exhalation into a CO breathalyzer at the end of the 8-hour Ad Libitum Smoking Session. Only very-low-nicotine-content (virtually nicotine-free) cigarettes were consumed in this session.

  2. Cigarette Discrimination Accuracy

    Time frame: One day (in the Cigarette Discrimination Session), over a 6-hour time frame.

    Participants sample 4 cigarettes of type A and 4 cigarettes of type B in a double-blind manner and indicate for each cigarette if they think it is of type A or B. Two reference trials with cigarette type unblinded will be performed before the first and fifth sample cigarette. For each sampled cigarette, the score is either 1 (correct) or 0 (incorrect). Discrimination accuracy is calculated by averaging the eight scores for each participant.

Secondary outcomes

  1. Change in the Number of Research Cigarettes Smoked

    Time frame: One day (in the Ad Libitum Smoking Session), over an 8-hour time frame.

    In the Ad Libitum Smoking Session, participants can smoke as many research cigarettes (all very-low-nicotine-content) as they wish. The propensity to maintain smoking despite the absence of nicotine was quantified by subtracting the number of cigarettes smoked in the last two hours from that in the first two hours of the session. Smaller difference values indicate that smoking was upheld by very-low-nicotine-content cigarettes.

  2. Difference in Subjective State Composite Score

    Time frame: One day (in the Cigarette Discrimination Session), over a 6-hour time frame.

    The measure is derived by transforming scores on the Minnesota Nicotine Withdrawal Scale (where higher values signify more withdrawal), the Affect-based Withdrawal Scale (higher values signify a worse emotional state), Questionnaire for Smoking Urges (higher values indicate more craving), and modified Cigarette Evaluation Questionnaire (mCEQ, higher values indicate greater subjective effects of smoking on mood, hunger, physiology) into standard z-scores, thus giving each scale a mean of 0 and standard deviation of 1. Withdrawal and craving scores were re-poled (inversing the sign), and scales were averaged for each subject. The resulting composite quantified the subjective state response to cigarette smoking, larger values indicating less withdrawal, less craving, and larger effects on the mCEQ. The difference therein between the research cigarettes containing nicotine and those containing almost no nicotine quantified the subjective state response to nicotine.

Sponsors and collaborators

Lead sponsor

University of Maryland, Baltimore

Other

Registry information

Official study title

Cigarette Smoking in Smokers With and Without a Diagnosis of Schizophrenia

Important dates

Study start
2021
Primary completion
2022
Study completion
2022
First posted
Jun 27, 2019
Registry last updated
Sep 26, 2024

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.