The complex genetic and psychosocial influences on polysubstance misuse

Prevalence and correlates of driving under the influence of stimulants: Evidence from a national sample

BACKGROUND

Several million Americans use illicit stimulants every month and national data suggest stimulant use is increasing. However, little evidence exists that examines the prevalence and correlates of driving under the influence of stimulants (DUIS). The present study aimed to provide new evidence on the prevalence of DUIS in the U.S. adult population.

METHODS

This study examined data from 170,944 adults 18 and older in the 2016-2019 National Survey on Drug Use and Health. Using Stata and R, we estimated the prevalence and key correlates of DUIS among adults in the United States.

RESULTS

The overall prevalence of DUIS was 0.7% among adults in general and 28.3% among past-year stimulant users. Among the full adult sample, the prevalence of DUI cocaine was 0.5% and the prevalence of DUI methamphetamine was 0.3%. More than one in five (21.6%) adults with past year cocaine use reported DUI of cocaine, while nearly one half (47.2%) of adults with past year methamphetamine use reported DUI of methamphetamine. There is also a substantially higher likelihood of driving under the influence of stimulants among individuals reporting early onset of use and among those meeting criteria for cocaine/methamphetamine use disorders. Among adults who used cocaine/methamphetamine, those who reported driving under the influence of stimulants were more than 2 times more likely to experience a depressive episode or psychological distress.

CONCLUSION

Findings suggest that prevention/treatment approaches focused on multiple substances as well as mental health needs may be most appropriate for addressing the challenge of DUIS.

Toward a typology of hallucinogen users in the United States

BACKGROUND

Roughly one in ten American adults have used hallucinogens, and emerging evidence suggests that the prevalence of use is increasing. However, our understanding of the degree to which individuals "specialize" in the use of a particular hallucinogen or are poly-hallucinogen users remains incomplete.

METHODS

This study examined data from 6381 individuals reporting past-year hallucinogen use in the 2016-2018 National Survey on Drug Use and Health. Logistic regression examined the association between the number of distinct hallucinogens used and psychosocial/behavioral risks, and latent class analysis (LCA) characterized subgroups of hallucinogen users.

RESULTS

The vast majority of hallucinogen users, roughly 70%, are not "specialists" who use only one hallucinogen type; rather, lifetime poly-hallucinogen use is the norm. Critically, however, we also see that important differences exist within the population of hallucinogen users-half (51%) could be classified as LSD-Mushroom-Ecstasy users only (this group was disproportionally comprised of youth), nearly one third (30%) were Poly-Hallucinogen users (this group was disproportionately male and non-Hispanic White), and smaller proportions were limited primarily to use of LSD-Mushrooms (6%; these individuals were almost exclusively ages 35 and older) or Ecstasy Only (12%; these individuals were mostly younger adults ages 18-34).

CONCLUSIONS

Findings provide a fresh contribution to our understanding of poly-hallucinogen use in a time in which local and state governmental leaders, and people across the country, weigh the benefits and drawbacks of legalizing specific hallucinogenic drugs.

Molecular genetics of substance use disorders: An umbrella review

BACKGROUND

Substance use disorders (SUD) are a category of psychiatric disorders with a large epidemiological and societal impact around the world. In the last decades, a large number of genetic studies have been published for SUDs.

METHODS

With the objective of having an overview and summarizing the evidence published up to date, we carried out an umbrella review of all the meta-analyses of genetic studies for the following substances: alcohol, tobacco, cannabis, cocaine, opioids, heroin and methamphetamines. Meta-analyses for candidate gene studies and genome-wide association studies (GWAS) were included.

RESULTS

Alcohol and tobacco were the substances with the largest number of meta-analyses, and cannabis, opioids and cocaine the least studied. The following genes were associated with two or more SUDs: OPRM1, DRD2, DRD4, BDNF and SL6A4. The only genes that had an OR higher than two were the SLC6A4 for all addictions, the ADH1B for alcohol dependence, and BDNF for methamphetamine dependence. GWAS confirmed the possible role of CHRNA5 gene in nicotine dependence and identified novel candidate genes in other SUDs, such as FOXP2, PEX and, AUTS2, which need further functional analyses.

CONCLUSIONS

This umbrella review summarizes the evidence of 16 years of research on the genetics of SUDs and provides a broad and detailed overview of results from more than 150 meta-analyses for SUD. The results of this umbrella review will guide the need for future genetic studies geared toward understanding, preventing and treating SUDs.

Genome-wide association analysis of opioid use disorder: A novel approach using clinical data

BACKGROUND

Opioid use disorder (OUD) represents a large and pervasive global public health challenge. Previous genetic studies have demonstrated the significant heritability of OUD and identified several single-nucleotide polymorphisms (SNPs) associated with its prevalence.

METHODS

In this paper, we conducted a genome-wide association analysis on opioid use disorder that leveraged genetic and clinical data contained in a biobank of 21,310 patients of European ancestry. We identified 1039 cases of opioid use disorder based on diagnostic codes from nearly 16 million encounters in electronic health records (EHRs).

RESULTS

We discovered one novel OUD-associated locus on chromosome 4 that was significant at a genome-wide threshold (p = 2.40 × 10^-8). Heritability analysis suggested that common SNPs explained 0.06 (se 0.02, p = 0.0065) of the phenotypic variation in OUD. When we restricted controls to those with previous opioid prescriptions, we were able to further strengthen the original signal and discovered another significant locus on chromosome 16. Pair-wise genetic correlation analysis yielded strong positive correlations between OUD and two other major substance use disorders, alcohol and nicotine, with the strongest correlation between nicotine and opioid use disorder (genetic correlation 0.65, se = 0.19, p = 0.00048), suggesting a significant shared genetic component across different substance disorders.

CONCLUSIONS

This pragmatic, clinically-focused approach may supplement more traditional methods to facilitate identification of new genetic underpinnings of OUD and related disorders.