Nicotinic Receptor Density in Smoking and Nonsmoking Schizophrenics

Withdrawn before enrolling

Conditions studied: Schizophrenia

In brief

Background: \- Previous studies have suggested that smoking cigarettes affects the number of receptors in the brain for nicotine, a chemical present in cigarette smoke. The receptors play a role in an individual's ability to think and concentrate. Many people with schizophrenia and similar disorders smoke, and research suggests that smoking may temporarily improve concentration and focus in individuals with schizophrenia. Researchers are interested in studying both current smokers and nonsmokers with schizophrenia to determine whether smoking affects the number of nicotine receptors in the brains of people with schizophrenia. Objectives: \- To study the distribution and volume of nicotine receptors in the brains of individuals with schizophrenia who are either nonsmokers or current smokers. Eligibility: * Individuals between 18 and 50 years of age who have been diagnosed with schizophrenia and are either nonsmokers or current smokers (at least 10 cigarettes per day for the past year). * Current smokers must be able to give up smoking for 48 hours. Design: * This study involves an initial screening visit and up to five study visits. * After the screening visit, participants will have two sessions in which they will complete questionnaires about thoughts, memory, and smoking habits. Smokers will also have nicotine blood and carbon monoxide breath levels taken during these sessions, before and after smoking a cigarette. * Participants will have sessions with imaging studies (e.g., magnetic resonance imaging) to provide baseline measurements for later tests, and will also have tests to measure brain electrical activity. * Participants will have a positron emission tomography (PET) scanning session to examine the nicotine receptors in the brain. Participants will need to stay overnight (nonsmokers) or for 2 nights (smokers) as an inpatient before the session. The PET scan session will take up to 6 hours, although participants will only be in the scanner for up to 3 hours. * Participants will have a follow-up phone call with study researchers 1 week after the PET scanning session.

Key facts

Study ID: NCT01246128
Run by: National Institute on Drug Abuse (NIDA)
People needed: 0
Starts: 2010-10-31
Expected to finish: 2011-07-12
Last updated by the study team: 2017-07-02

Who can join

Age: 18 and older, up to 50. Sex: any. Healthy volunteers: accepted.

You may not qualify if…

Weight: Anyone weighing more than 300 lbs is excluded from the study. The purpose of this exclusion is the weight limit of the PET scanner.
History of Drug Abuse: Participants reporting current or having a significant history of illicit drug abuse will be excluded from the study. Subjects may use moderate amounts of alcohol and caffeine and smoke an occasional marijuana cigarette, but must not be dependent on alcohol, caffeine or marijuana. No alcohol or marijuana for at least 72 hours prior to scanning. No smoking for 48 hrs before the PET scan.
Current Medication Use: Participants will continue to use their prescription medications. The following hypertension medications will be exclusionary: Indapamide, spironolactone, clonidine, guanfacine, methyldopa, propranolol. Over the counter medications are not exclusionary, however, subjects will not be allowed to use over the counter medications in the week prior to their PET scan.
CNS disease: History of known structural brain abnormalities (e.g., neoplasm, subarachnoid cysts), cerebrovascular disease, infectious disease (e.g., abscess), history of head trauma (defined as documented loss of consciousness for 5 min or greater), history of seizures as an adult, sleep apnea.
Cardiovascular, pulmonary, or systemic disease: Untreated hypertension known arrhythmia, symptomatic or known coronary artery disease; history of endocarditis, cerebral embolism, obstructive pulmonary disease, asthma, active tuberculosis, known endocrine disease (derangements in adrenal, thyroid, bone or reproductive function) known chronic renal or hepatic dysfunction, known HIV seropositive, known current autoimmune disease involving the CNS, type I diabetes mellitus. Subjects with type II diabetes mellitus will be allowed if their Hb A1C is less than 7.
Special considerations for female subjects. Female participants who are planning to become pregnant, currently pregnant or nursing will not be allowed to participate in this study because of potential damage to the fetus or baby from the radiation. In addition, women of child bearing age who are sexually active are required to use an effective form of birth control for the duration of the study. Effective forms of birth control include:
hormonal contraceptives (birth control pills, injectable hormones, vaginal ring hormones),
surgical sterility (tubal ligation or hysterectomy)
IUD
Diaphragm with spermicide
Condom with spermicide
Female subjects will be given a serum pregnancy test (quantitative beta HCG) within 24 hours of the PET study. Menstrual cycle phase or sex has not been shown to affect receptor availability (Cosgrove et al., 2007).
Radiation exposure: Any subject who has participated in any research studies in which he/she received a radiation exposure that would result in combination with the present study, in a total effective radiation exposure (from research studies) exceeding 5.0 rem in a year.
Children under the age of 18 will be excluded to avoid unnecessary exposure to radiation to these populations.
Presence in body of metallic implants or materials that could be moved by the magnet of the MRI scanner: pacemakers, surgical implants, aneurysm clips, dental braces, bullet(s) or other metallic materials.

Where it is running

Johns Hopkins University — Baltimore, Maryland, United States
Maryland Psychiatric Research Center (MPRC) 55 Wade Avenue — Catonsville, Maryland, United States

Full record on ClinicalTrials.gov

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