Study 46 – Advancing Genomics Research of Substance Use Disorders in Latin American Populations

Principal Investigators: Janitza Montalvo-Ortiz, Ph.D., Humberto Nicolini, Ph.D

dbGaP Accession ID:  phs003558.v1.p1

dbGaP Release Date: 05/01/2025

Objective: Latin American populations are widely underrepresented in genomic studies of substance use disorders. This project aims to analyze the genetics of substance use disorders in Latin American populations, thus increasing the representation of this population in such studies, particularly from Mexico, Chile, and Brazil.

Significance/Impact: Genetics of substance use disorders has advanced in the last decade, thanks to recent large-scale genome-wide association studies (GWAS). However, few GWAS have included Latin American populations, reflecting a general underrepresentation in psychiatric genomic research. Increasing the representation of Latin Americans is essential to identify common risk variants across ancestries as well as Latin American-specific associated variants. Diversifying GWAS data and analysis is critical to ensure that the potential benefits of GWAS findings (e.g., personalized medicine) are shared beyond European populations.

Study Design/Methodology:

This study will include the following three cohorts:

The Mexican Genomic Database for Addiction Research (MxGDAR) is a subsample derived from the Mexican National Survey of Tobacco, Alcohol, and Drug use. The survey was carried out in two phases, with biological sampling performed in the second phase. There were questionnaires in each phase: the first focused on sociodemographic, social, and interpersonal information, with a section on patterns of alcohol, tobacco, and drug use. The MxGDAR is a nationally representative cohort and provided informed consent.

The Chilean cohort was recruited at University of the Andes Hospital, Pontifical Catholic University Network – Christus San Carlos de Apoquindo Hospital and La Florida’s Hospital, all in Santiago, Chile, as outpatients or inpatients. Inclusion criteria were: 1) age 18 to 80; 2) Diagnosis of BD type I or II according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria and confirmed using the Structured Clinical Interview for DSM Disorders (SCID); 3) written informed consent. Exclusion criteria were: 1) history of congenital cardiac disease; 2) use of any medication within 5 half-lives with known effects on the QTc interval, except for psychotropic drugs; 3) use of stimulants or pseudoephedrine in the last 2 days; 4) current psychotic symptoms; 5) suicidal ideation with a suicide plan. 20% of this cohort has substance use disorder diagnosis.

The Brazilian cohort includes 800 individuals with substance use disorders.  These are all men diagnosed according to DSM-V in male inpatient treatment units in Sao Paulo, Brazil.


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