Influence of Nicotine on Cognitive Function in Schizophrenic Patients With and Without Comorbid Drug Dependence



Status:Completed
Conditions:Schizophrenia, Psychiatric
Therapuetic Areas:Psychiatry / Psychology
Healthy:No
Age Range:18 - 60
Updated:3/14/2019
Start Date:May 14, 2006
End Date:January 22, 2013

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Background:

- Individuals with schizophrenia have a significantly higher tendency to develop substance
abuse or dependence than the general population. For instance, people with schizophrenia
smoke much more than the general population, and many are dependent on street drugs such
as cocaine and heroin. However, these individuals are rarely included in research
studies that might provide more information about treatments for both schizophrenia and
substance abuse.

- Strong evidence suggests that schizophrenia and substance dependence have similar
effects on the brain, affecting attention, memory, and eye movement. Other research
indicates that schizophrenia and substance dependence affect the same parts of the
dopamine system, contributing to problems in brain function that require treatment.
These new developments provide a strong rationale to study the combination of
schizophrenia and substance dependence.

- Nicotine may help improve brain function and thinking in individuals with both
schizophrenia and drug dependence. Some of the thinking and memory problems experienced
by these individuals can be treated with nicotine. However, more research is needed to
determine exactly how nicotine affects individuals with both schizophrenia and drug
dependence.

Objectives:

- To determine whether individuals with schizophrenia and drug dependence show impairment
in tests of eye tracking, attention, and memory compared with healthy control subjects.

- To evaluate the effect of nicotine on eye tracking, attention, and memory in individuals
with both schizophrenia and substance dependence.

Eligibility:

- Current smokers (at least 10 cigarettes per day for the past year) between 18 and 55 years
of age who (1) have been diagnosed with schizophrenia/schizoaffective disorder, (2) have been
diagnosed with schizophrenia/schizoaffective disorder and are currently using heroin and/or
cocaine, or (3) are healthy individuals with no family history of psychotic illness.

Design:

- The study will consist of one training session and three testing sessions. Each session
will last about 2 hours.

- The training session will introduce participants to the study tests and evaluate their
tolerance of the nicotine nasal spray used in the study. Participants who cannot
tolerate the higher dose of the spray will not continue in the study.

- At the start of each testing session, smokers will have one cigarette to standardize the
time of the most recent exposure to nicotine.

- During the testing sessions, participants will receive a placebo spray, a lower dose of
nicotine, or a higher dose of nicotine, and then will be asked to perform tests that
evaluate attention, memory, and other thinking tasks.

Objective:

Specific aim 1: To test the hypothesis that individuals with comorbid schizophrenia and drug
dependence will show impaired neurocognitive functions in anticipatory learning of
eyetracking, attention, and memory performance compared to healthy controls subjects.

Specific aim 2: To test the hypothesis that nicotine will dose-dependently improve
anticipatory learning of eyetracking, attention, and memory performance in individuals with
comorbid schizophrenia and substance dependence.

Study Population:

Male and nonpregnant-female smokers 18 to 55 years of age, from the following subject groups:
(1) patients with a DSM IV diagnosis of schizophrenia (2) patients with dual DSM IV diagnoses
of schizophrenia and heroin and/or cocaine dependence or abuse, or on methadone or
beprenorphine maintenance and (3) healthy individuals with no family history of psychotic
illness.

Design:

This study will be a double-blind, placebo controlled trial of nicotine or placebo nasal
sprays. Participants will have four visits. After the training session, participants will be
administered one dose (0, 1 or 2 mg) of nicotine nasal spray during each of the 3
experimental sessions. The dose will be given 5 minutes prior to the cognitive task
batteries.

Outcome Measures:

Vital signs, moods, and performance on tasks assessing eye movement (initiation latency,
initiation acceleration, closed-loop pursuit gain), attention (Continuous Performance and
Digit Symbol Substitution Tasks), and memory (delayed recognition and nback).

- INCLUSION CRITERIA:

All participants must meet the following criteria:

- age 18 60

- smoke 10 or more cigarettes/day for at least the past year

Experimental groups 1 and 2, additional criteria:

-DSM-IV diagnosis of schizophrenia or schizoaffective disorder (assessments pertaining to
these diagnoses will be done in other MPRC screening protocols).

Experimental group 2, additional criteria:

-DSM-IV diagnosis of abuse or dependence on cocaine and/or heroin or on methadone or
buprenorphine maintenance.

EXCLUSION CRITERIA:

Comprehensive medical history:

-Exclusions: Heart disease, uncontrolled blood pressure (persistent systolic above 155 or
diastolic above 95), neurological conditions (stroke, seizure, history of head injury),
asthma, emphysema, chronic bronchitis, chronic obstructive pulmonary disease, pathology of
nasal passages that precludes the effective administration of nicotine nasal spray.

Drug Use Survey

All subjects:

- Exclude if treatment for tobacco dependence during the previous 6 months.

- Healthy controls and schizophrenic patients without comorbid drug abuse or dependence:
Exclude if history alcohol or other substance dependence ever, or alcohol or other
substance abuse in the past year. Verify abstinence from controlled substances with
urine screen (Iscreen). Participants in the above 2 groups who are positive for any
illicit drug (with the exception of marijuana) will be excluded.

Structured Clinical Interview for DSM-IV

-Healthy controls: exclude if any current psychiatric disorder

Urine pregnancy for females:

-Exclude if positive.
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