Cigarette Smoking in Smokers With and Without Schizophrenia

June 6, 2024 updated by: Britta Hahn, University of Maryland, Baltimore

Cigarette Smoking in Smokers With and Without a Diagnosis of 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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
31

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Maryland
      • Catonsville, Maryland, United States, 21228
        • Maryland Psychiatric Research Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 60 years (Adult)

Accepts Healthy Volunteers

Yes

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Other: Smokers with schizophrenia
This is a diagnostic group, defined independently from this study.
Combination product: Sampling Research Cigarettes
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.
Other: Smokers without schizophrenia
This is a diagnostic group (i.e., no diagnosis of schizophrenia), defined independently from this study.
Combination product: Sampling Research Cigarettes
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.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
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.
One day (in the Cigarette Discrimination Session), over a 6-hour time frame.
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.
One day (in the Ad Libitum Smoking Session), over an 8-hour time frame.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
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.
One day (in the Ad Libitum Smoking Session), over an 8-hour time frame.
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.
One day (in the Cigarette Discrimination Session), over a 6-hour time frame.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Maryland, Baltimore

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Britta Hahn, Ph.D., University of Maryland, Baltimore

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 15, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 23, 2022

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 23, 2022

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 24, 2019

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 26, 2019

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 27, 2019

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 26, 2024

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 6, 2024

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2024

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • HP-00086422

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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