This study is being done to find out if medicines that affect a neurotransmitter (chemical messenger) in the brain called adenosine improve behavioral problems that are related to drug abuse. Another purpose of the study is to find out how genes related to adenosine change how people respond to these medicines. More information about how these medicines change behaviors may be helpful to come up with new treatments for drug abuse.
Specific Aims: Aim 1. To characterize the behavioral and subjective effects of acute caffeine administration in cocaine-dependent subjects, using laboratory measures of impulse control, drug discrimination (with d-amphetamine as the training dose), and subjective effects. Hypotheses related to Aim 1: 1. Subjects will show decreases in impulsivity (delay to reward and response inhibition) after acute oral doses of caffeine compared to placebo. 2. Subjects will show some stimulant-like subjective effects following acute oral doses of caffeine, but not the euphoric effects that would predict abuse potential.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
QUADRUPLE
Enrollment
23
Across five separate testing days, subjects were administered two placebo doses, 20 mg amphetamine, 150 mg caffeine, and 300 mg caffeine in counterbalanced fashion
Across five separate testing days, subjects were administered two placebo doses, 20 mg amphetamine, 150 mg caffeine, and 300 mg caffeine in counterbalanced fashion
Across five separate testing days, subjects were administered two placebo doses, 20 mg damphetamine,150 mg caffeine, and 300 mg caffeine in counterbalanced fashion
The University of Texas Health Science Center, Houston
Houston, Texas, United States
Visual Analog Scale Subjective Rating of Drug Effects
Visual Analog Scale Rating. Scores range from 0 to 100 with higher scores meaning greater intensity of response being rated.
Time frame: Immediately after dose
Systolic and Diastolic Blood Pressure
Sitting Blood Pressure
Time frame: Average across 7 time points: Immediately after dose and every 30 minutes for 3 hours
Heart Rate
Sitting heart rate
Time frame: Average across 7 time points: Immediately after dose and every 30 minutes for 3 hours
Addiction Research Center Inventory Subjective Rating of Drug Effects
Addiction Research Center Inventory (ARCI 49). T/F scales with 49 items. Includes the following subscales: Morphine-Benzedrine Group (MBG), includes euphoria (0 to +16, higher numbers = more euphoria) Phenobarbital-Chorpromazine-Alcohol Group (PCAG), includes sedation (-3 to +11, higher scores = more sedation) Lysergic Acid Diethylmide Group (LSD) , includes dysphoria and agitation (-4 to +10, higher scores = more dysphoria) Amphetamine Group (A), includes stimulation ( 0 to +11, higher scores = more stimulation) Benzedrine Group (BG), includes energy and "intellectual efficiacy" (+4 to +9, higher scores = more energy)
Time frame: Immediately after dose
Drug Effects Questionnaire Rating of Subjective Ratings of Drug Effects
Assessments measured using a 4 item Drug Effects Questionnaire (DEQ) Ranges from 0 to 100 with higher numbers showing greater effect for each scale.
Time frame: Immediately after dose
Probabalistic Feedback Selection Task
Accuracy on a range from 0 to 1 of correctly performing a learning task, with 1 being the highest degree of accuracy.
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Across five separate testing days, subjects were administered two placebo doses, 20 mg damphetamine,150 mg caffeine, and 300 mg caffeine in counterbalanced fashion
Time frame: 75 minutes after dose
Saliva Caffeine and Paraxanthine Levels
Due to insufficient oral volume or breakage during sample transfer, data were lost or incomplete for two cocaine-dependent subjects. Analyses for the saliva data represent 11 cocaine-dependent subjects and 10 controls.
Time frame: 30 minutes prior to dose, 30/90/150 minutes post dose.