Filtering by
- All Subjects: Genetics
This project is an investigation of the gene by environment (GxE) interactions’ effect on substance use outcomes among refugee communities. Substance use disorders (SUDs) are a major public health concern, affecting individuals and communities worldwide. The etiology of SUDs is complex, involving a combination of genetic, environmental, and social factors. In recent years, there has been growing interest in the role of gene by environment interactions in the development of SUDs, particularly in vulnerable populations such as refugees. Refugee populations are exposed to a range of environmental stressors that may interact with genetic factors to increase their risk of SUDs. However, a number of studies describe a “refugee paradox,” where despite having been exposed to risk factors that can lead to SUDs, they are less likely to develop SUDs. Understanding these gene by environment interactions in refugee communities is crucial for not only understanding this phenomenon, but developing effective prevention and treatment strategies for this population. This thesis aims to investigate the gene by environment interactions underlying substance use in refugee communities and to analyze different methods for gene by environment analyses, ultimately determining which method is best suited for this population.
Structural equation modeling was used to test hypotheses. Results from an independent genome-wide association study of 5-hydroxyindoleacetic acid in the cerebrospinal fluid were used to create serotonin (5-HT) polygenic risk scores, wherein higher scores reflected lower levels of 5-HT functioning. Data from three time points were drawn from each sample, and all paths were prospective. Findings suggested that 5-HT polygenic risk did not predict self-regulatory constructs. However, 5-HT polygenic risk did predict the divergent outcomes of depression and aggression/antisociality, such that higher levels of 5-HT polygenic risk predicted greater levels of depression and aggression/antisociality. Results most clearly supported adolescents’ aggression/antisociality as a mechanism in the relation between 5-HT polygenic risk and later alcohol use. Deficits in self-regulation also predicted depression and aggression/antisociality, and indirectly predicted alcohol use through aggression/antisociality. These pathways to alcohol use might be the most salient for boys with low levels of socioeconomic status.
Results are novel contributions to the literature. The previously observed association between serotonin functioning and alcohol use might be due, in part, to the fact that individuals with lower levels of serotonin functioning are predisposed towards developing earlier aggression/antisociality. Results did not support the hypothesis that serotonin functioning predisposes individuals to deficits in self-regulatory abilities. Findings extend previous research by suggesting that serotonin functioning and self-regulation might be transdiagnostic risk factors for many types of psychopathology.