Associations between polygenic risk of substance use and use disorder and alcohol, cannabis, and nicotine use in adolescence and young adulthood in a longitudinal twin study

Alcohol use polygenic risk score, social support, and alcohol use among European American and African American adults

Alcohol use is influenced by genetic and environmental factors. We examined the interactive effects between genome-wide polygenic risk scores for alcohol use (alc-PRS) and social support in relation to alcohol use among European American (EA) and African American (AA) adults across sex and developmental stages (emerging adulthood, young adulthood, and middle adulthood). Data were drawn from 4,011 EA and 1,274 AA adults from the Collaborative Study on the Genetics of Alcoholism who were between ages 18-65 and had ever used alcohol. Participants completed the Semi-Structured Assessment for the Genetics of Alcoholism and provided saliva or blood samples for genotyping. Results indicated that social support from friends, but not family, moderated the association between alc-PRS and alcohol use among EAs and AAs (only in middle adulthood for AAs); alc-PRS was associated with higher levels of alcohol use when friend support was low, but not when friend support was high. Associations were similar across sex but differed across developmental stages. Findings support the important role of social support from friends in buffering genetic risk for alcohol use among EA and AA adults and highlight the need to consider developmental changes in the role of social support in relation to alcohol use.

Genetic influences on the interplay between obsessive-compulsive behavior symptoms and cannabis use during adolescence

INTRODUCTION

There are overlapping biological origins and behaviors associated with obsessive-compulsive symptoms (OCS) and cannabis use. There is also evidence that OCS and cannabis use are associated over time. Thus, we investigated polygenic predisposition for OCS as predictive of OCS and cannabis use from age 17 to 19. We hypothesized that greater genetic risk for OCS would predict both OCS and cannabis use.

METHODS

The current study used participants from the Project Alliance 1 study, a US-based sample, for whom genomic, OCS, and cannabis use data were available (n = 547). Polygenic risk scores (PRS) were formed via a meta-genome-wide association study on OCS and examined as a predictor of OCS and cannabis use at age 17 and 19. The sample was diverse (52.4% male; 45% European American, 30% African American, 14% multiracial, 5% Hispanic/Latino, 4% Asian American, and 2% other groups). Sensitivity analysis was performed by gender for European American and African American subsamples.

RESULTS

Across the whole sample, the greater polygenic risk for OCS was negatively associated with cannabis use at age 17 and positively associated with OCS at 19. Cannabis use at age 17 was positively associated with OCS at age 19. The association between polygenic risk for OCS and cannabis use at age 17 was replicated in European American males, whereas the association between cannabis use at age 17 and OCS at age 19 was replicated in African American males.

CONCLUSIONS

Cannabis use may exacerbate OCS through adolescence, and genetic predisposition for OCS may be associated with lower cannabis use in efforts to avoid exacerbation of OCS.

Phenome-wide Association Analysis of Substance Use Disorders in a Deeply Phenotyped Sample

BACKGROUND

Substance use disorders (SUDs) are associated with a variety of co-occurring psychiatric disorders and other SUDs, which partly reflects genetic pleiotropy. Polygenic risk scores (PRSs) and phenome-wide association studies are useful in evaluating pleiotropic effects. However, the comparatively low prevalence of SUDs in population samples and the lack of detailed information available in electronic health records limit these data sets' informativeness for such analyses.

METHODS

We used the deeply phenotyped Yale-Penn sample (n = 10,610 with genetic data; 46.3% African ancestry, 53.7% European ancestry) to examine pleiotropy for 4 major substance-related traits: alcohol use disorder, opioid use disorder, smoking initiation, and lifetime cannabis use. The sample includes both affected and control subjects interviewed using the Semi-Structured Assessment for Drug Dependence and Alcoholism, a comprehensive psychiatric interview.

RESULTS

In African ancestry individuals, PRS for alcohol use disorder, and in European individuals, PRS for alcohol use disorder, opioid use disorder, and smoking initiation were associated with their respective primary DSM diagnoses. These PRSs were also associated with additional phenotypes involving the same substance. Phenome-wide association study analyses of PRS in European individuals identified associations across multiple phenotypic domains, including phenotypes not commonly assessed in phenome-wide association study analyses, such as family environment and early childhood experiences.

CONCLUSIONS

Smaller, deeply phenotyped samples can complement large biobank genetic studies with limited phenotyping by providing greater phenotypic granularity. These efforts allow associations to be identified between specific features of disorders and genetic liability for SUDs, which help to inform our understanding of the pleiotropic pathways underlying them.

Clinical, environmental, and genetic risk factors for substance use disorders: characterizing combined effects across multiple cohorts

Substance use disorders (SUDs) incur serious social and personal costs. The risk for SUDs is complex, with risk factors ranging from social conditions to individual genetic variation. We examined whether models that include a clinical/environmental risk index (CERI) and polygenic scores (PGS) are able to identify individuals at increased risk of SUD in young adulthood across four longitudinal cohorts for a combined sample of N = 15,134. Our analyses included participants of European (NEUR = 12,659) and African (NAFR = 2475) ancestries. SUD outcomes included: (1) alcohol dependence, (2) nicotine dependence; (3) drug dependence, and (4) any substance dependence. In the models containing the PGS and CERI, the CERI was associated with all three outcomes (ORs = 01.37-1.67). PGS for problematic alcohol use, externalizing, and smoking quantity were associated with alcohol dependence, drug dependence, and nicotine dependence, respectively (OR = 1.11-1.33). PGS for problematic alcohol use and externalizing were also associated with any substance dependence (ORs = 1.09-1.18). The full model explained 6-13% of the variance in SUDs. Those in the top 10% of CERI and PGS had relative risk ratios of 3.86-8.04 for each SUD relative to the bottom 90%. Overall, the combined measures of clinical, environmental, and genetic risk demonstrated modest ability to distinguish between affected and unaffected individuals in young adulthood. PGS were significant but added little in addition to the clinical/environmental risk index. Results from our analysis demonstrate there is still considerable work to be done before tools such as these are ready for clinical applications.