Endophenotype for Alcohol Misuse in Healthy Minority Populations

Defining an Endophenotype for Alcohol Misuse: A Focus On Minority Populations

The purpose of the study is to understand the relationship between what an individual inherited from their family (genetics), how they respond and feel after drinking alcohol, and how they respond to pre-treatment with naltrexone, a medication that blocks some of the effects of alcohol and is approved for the treatment of alcoholism. The investigators are conducting this study on those of African descent because there is almost no research focused on this group and the association with genetics. The investigators seek to enroll 40 people in the study. Participation will consist of 4 different alcohol challenge sessions in a cross over design. Each session will be separated by at least 10 days. In total, there will be four challenge sessions.

We propose to test the degree to which specific genetic markers alter the relationship between subjective and objective measures of response to alcohol ingestion among non-alcohol dependent adults of African descent in a laboratory environment. To meet this aim, non-alcohol dependent adults of African descent will be recruited for participation to meet the N-goal of 40 trial completers. After consenting, genotyping, and completing the baseline assessment, they will participate in four separate alcohol challenge sessions separated by at least 10 days. During each of the sessions, subjects will be administered alcohol or sham drinking challenge sessions and pretreatment with either naltrexone (50 mg/day) or placebo in a double-blind fashion. The order of the four sessions will be randomly assigned. During each session, physiological and subjective response will be measured. We will select subjects to assure equal number of participants with at least one copy of the Val6 allele compared to those homozygous for the Ala6 allele.

Inclusion Criteria:

• Male or female and 21 years of age or older
• Drinks less than an average of 21 drinks/week with no more than 2 binge episodes per week
• Of African descent by self report

Exclusion Criteria:

• Meets DSM-IV criteria for lifetime dependence on any substance other than nicotine
• Subjects who test positive on the urine drug screen for opioids, cocaine, marijuana, or amphetamine at the screening visit
• Subjects who meet current or lifetime DSM-IV criteria for bipolar affective disorder, schizophrenia, or any psychotic disorder
• The presence of unstable or serious medical illness; including history of stroke, seizure disorder, severe liver disease (AST or ALT > 5X normal at the time of randomization), or unstable cardiac disease
• Needs treatment with any psychotropic medication (antidepressant, antipsychotic, benzodiazepine, or mood stabilizing medication)
• Pre-menopausal female subjects who are pregnant, nursing, or not using a reliable method of contraception
• Insulin-dependent diabetes
• Any medical or psychological condition that could jeopardize the subject's safe participation in the trial as determined by the PI.