Inclusion Criteria:  Age 35-70 years English or Spanish speaking Alcohol users Cognitive impairment Current CD4>350  Exclusion Criteria:  Diagnosed major psychiatric illness Consumption of over 300 drinks in the past 30 days Recent opioid use Lifetime history of medically-assisted alcohol detoxification Inpatient or intensive treatment for addictive behaviors in the past 12 months MRI contraindications Current antibiotic treatment Current probiotic use Physical impairment precluding motor response or lying still.