Caffeine and Cocaine

Phase 1

Completed

Interventions: Drug: Caffeine 150 MG
Drug: Amphetamine
Drug: Placebo
Drug: Caffeine 300 MG

Brief Summary: 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.

Detailed Description: 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.

Recruitment & Eligibility

Inclusion Criteria

Subjects who currently meet DSM-IV criteria for cocaine dependence and healthy controls
At least one cocaine positive urine during screening.
Current regular consumption of caffeine.
Female subjects: a negative pregnancy test.

Exclusion Criteria

Current or past DSM-IV Axis I disorder other than substance abuse/ dependence
Any significant non-psychiatric medical illness requiring ongoing medical treatment or which would preclude treatment with d-amphetamine or caffeine
Substance dependence other than cocaine within the last 3 months.
Positive breath alcohol.
Positive urine drug screen for drugs other than cocaine or THC at the time of behavioral testing
For female subjects: known pregnancy or a positive pregnancy test or current breast feeding.
Diagnosis of Adult Attention Deficit Disorder as determined by: a) meeting DSM-IV criteria for childhood ADHD, b) currently has impairing ADHD symptoms, c) ADHD symptoms can not have remitted at any period since childhood.
HIV positive.
I.Q. below 70.

Arm && Interventions

Primary Outcome Measures

Name	Time	Method
Systolic and Diastolic Blood Pressure	Average across 7 time points: Immediately after dose and every 30 minutes for 3 hours	Sitting Blood Pressure
Addiction Research Center Inventory Subjective Rating of Drug Effects	Immediately after dose	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)
Visual Analog Scale Subjective Rating of Drug Effects	Immediately after dose	Visual Analog Scale Rating. Scores range from 0 to 100 with higher scores meaning greater intensity of response being rated.
Heart Rate	Average across 7 time points: Immediately after dose and every 30 minutes for 3 hours	Sitting heart rate
Drug Effects Questionnaire Rating of Subjective Ratings of Drug Effects	Immediately after dose	Assessments measured using a 4 item Drug Effects Questionnaire (DEQ) Ranges from 0 to 100 with higher numbers showing greater effect for each scale.

Secondary Outcome Measures

Name	Time	Method
Probabalistic Feedback Selection Task	75 minutes after dose	Accuracy on a range from 0 to 1 of correctly performing a learning task, with 1 being the highest degree of accuracy.
Saliva Caffeine and Paraxanthine Levels	30 minutes prior to dose, 30/90/150 minutes post dose.	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.