Prevalence of cannabis use among tobacco smokers: a systematic review protocol

Epigenetic effects of cannabis: A systematic scoping review of behavioral and emotional symptoms associated with cannabis use and exocannabinoid exposure

BACKGROUND

Recent research suggests that epigenetic modifications may mediate the behavioral effects of cannabis, influencing exocannabinnoids' long term effects in cognitive function and its role in the emergence of psychotic symptoms.

BASIC PROCEDURES

In this systematic scoping review, we assessed the current evidence of epigenetic effects associated with the use of cannabis or exocannabinoid administration and their relationship with behavioral and emotional symptoms. We searched PubMed, Cochrane CENTRAL, and Web of Science, up to January 2022, using the terms "cannabis" and "epigenetics." The search yielded 178 articles, of which 43 underwent full article revision; 37 articles were included in the review.

MAIN FINDINGS

The gathered evidence included observational cross-sectional studies conducted on human subjects and experimental designs using animal models that conveyed disparity in administration dosage, methods of cannabis use assessment and targeted epigenetic mechanisms. Nine studies performed epigenome-wide analysis with identification of differentially methylated sites; most of these studies found a global hypomethylation, and enrichment in genes related to cellular survival and neurodevelopment. Other studies assessed methylation at specific genes and found that cannabis exposure was associated with reduced methylation at Cg05575921, DNMT1, DRD2, COMT, DLGAP2, Arg1, STAT3, MGMT, and PENK, while hypermethylation was found at DNMT3a/b, NCAM1, and AKT1.

CONCLUSIONS

The review found evidence of an exocannabinoid-induced epigenetic changes that modulate depressive-anxious, psychotic, and addictive behavioural phenotypes. Further studies will require dosage exposure/administration uniformization and a customized pool of genes to assess their suitability as biomarkers for psychiatric diseases.

E-cigarette and combustible cigarette cessation patterns, reasons, and methods among adolescents, young adults, and adults

Research is limited regarding adolescents' and young adults' (AYA) patterns, methods of, and reasons for cigarette or e-cigarette cessation. Further, while adults may try to use e-cigarettes to quit combustible cigarettes, little is known about how adults then quit e-cigarettes. This study utilizes a national, cross-sectional online survey of 6131 diverse participants aged 13-40 years to examine reasons for quitting e-cigarettes or cigarettes, quit methods, and quit attempt outcomes among AYAs and adults. In our sample, 3137 (51.2%) had ever used an e-cigarette, of whom 2310 (37.7%) were aged 13-24 years and 827 (13.5%) were 25-40 years old; 2387 (38.9%) had ever used a combustible cigarette (1440 [23.5%] were 13-24 years old and 947 [15.4%] were 25-40 years old). Among e-cigarette ever-users, 39.4% of 13-24-year-olds intended to quit in the next 6 months, and 36.9% had a serious plan for quitting in the next 30 days; 25.2% wanted to decrease the amount they used while 34.8% wanted to quit completely. Similar rates were found among e-cigarette ever users aged 25-40 years, as well as past 30-day e-cigarette users, cigarette ever-users, and past 30-day cigarette users across all ages. "Cold turkey" (41.0%) followed by "tried to cut down slowly by vaping/smoking less often or fewer puffs" (25.5%) was the most common quit method among e-cigarette ever-users and cigarette ever-users of all ages. Further study of effective tobacco cessation methods to help both AYAs and adults successfully quit nicotine, whether from cigarettes or e-cigarettes, is urgently needed.