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Purpose

The purpose of this study is to establish the dose-response curve for therapeutic doses of d-amphetamine on tasks of motivation and reward learning in the same participants and to use d-amphetamine as a dopaminergic probe to test newer theories about the role of dopamine in reward-related decision-making.

Condition

Eligibility

Eligible Ages
Between 18 Years and 35 Years
Eligible Genders
All
Accepts Healthy Volunteers
Yes

Inclusion Criteria

  • Healthy individuals

Exclusion Criteria

  • Individuals with a body mass index (BMI) <19 or >26, as this alters dosing requirements - Individuals with high blood pressure, abnormal Electrocardiography (EKG), any medical condition requiring regular medication (except birth control), any other regular use of a drug or supplement with potentially hazardous interactions with d-amphetamine (e.g. St. John's wort), or any other medical contraindication to amphetamine administration as determined by our study physician - Individuals who report no prior experience with recreational drugs of any kind (including alcohol), or who report a previous adverse reaction to amphetamine - Individuals with a current Diagnostic and Statistical Manual of Mental Disorders-V (DSM-V) Axis I diagnosis, excluding mild Substance Use Disorders (≤ 3 symptoms) - Individuals with a lifetime history of moderate to severe Substance Use Disorder (≥ 4 symptoms), mania or psychosis. - Women who are pregnant. - individuals smoking more than 10 cigarettes per week will also be excluded, to avoid confounding the effects of nicotine withdrawal with the effects of the study drugs/procedures, as participants will not be allowed to smoke during the sessions. - individuals with less than a high-school level of education or fluency in English will be excluded as our questionnaires require high-school level fluency in English, and have not been translated and validated in other languages.

Study Design

Phase
Phase 1
Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel Assignment
Primary Purpose
Basic Science
Masking
Single (Participant)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Placebo, then 10 mg d-amphetamine, then 20mg d-amphetamine
  • Drug: 10 mg d-amphetamine
    10 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: 20mg d-amphetamine
    20 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: Placebo
    Placebo dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
Experimental
Placebo, then 20 mg d-amphetamine, then 10mg d-amphetamine
  • Drug: 10 mg d-amphetamine
    10 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: 20mg d-amphetamine
    20 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: Placebo
    Placebo dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
Experimental
10 mg d-amphetamine, then placebo, then 20mg d-amphetamine
  • Drug: 10 mg d-amphetamine
    10 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: 20mg d-amphetamine
    20 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: Placebo
    Placebo dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
Experimental
10 mg d-amphetamine, then 20mg d-amphetamine, then placebo
  • Drug: 10 mg d-amphetamine
    10 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: 20mg d-amphetamine
    20 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: Placebo
    Placebo dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
Experimental
20 mg d-amphetamine, then 10mg d-amphetamine, then placebo
  • Drug: 10 mg d-amphetamine
    10 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: 20mg d-amphetamine
    20 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: Placebo
    Placebo dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
Experimental
20 mg d-amphetamine, then placebo, then 10mg d-amphetamine
  • Drug: 10 mg d-amphetamine
    10 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: 20mg d-amphetamine
    20 mg d-amphetamine dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.
  • Drug: Placebo
    Placebo dose given (double-blind) and behavioral tasks (EEfRT, PRT, ELT, CGT) administered.

More Details

Status
Completed
Sponsor
The University of Texas Health Science Center, Houston

Study Contact

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.