The effects of simultaneous alcohol and cannabis use on subjective drug effects: A narrative review across methodologies.

Over 75% of young adults who use cannabis also report drinking alcohol, leading to increased risks that include impaired cognition, substance use disorders, and more heavy and frequent substance use. Studies suggest that subjective responses to either alcohol or cannabis can serve as a valuable indicator for identifying individuals at risk of prolonged substance use and use disorder. While laboratory studies show additive effects when alcohol and cannabis are used together, the impact of co-using these substances, specifically with respect to cannabidiol, on an individual's subjective experience remains unclear. This narrative review explores the effects of simultaneous alcohol and cannabis (SAM) use on subjective drug effects, drawing from qualitative research, laboratory experiments, and naturalistic studies. Experimental findings are inconsistent regarding the combined effects of alcohol and cannabis, likely influenced by factors such as dosage, method of administration, and individual substance use histories. Similarly, findings from qualitative and naturalistic studies are mixed regarding subjective drug effects following SAM use. These discrepancies may be due to recall biases, variations in assessment methods, and the measurement in real-world contexts of patterns of SAM use and related experiences. Overall, this narrative review highlights the need for more comprehensive research to understand more fully subjective drug effects of SAM use in diverse populations and settings, emphasizing the importance of frequent and nuanced assessment of SAM use and subjective responses in naturalistic settings.

Cannabis use breaks in young adults: The highs and lows of tolerance breaks.

BACKGROUND/PURPOSE: Cannabis tolerance breaks, or T-breaks, are believed to benefit persons who use cannabis (PUCs) by decreasing tolerance levels to cannabis. However, no prior research, to our knowledge, has compared the effects of T-breaks and other use breaks on cannabis use patterns and outcomes. The current study examined whether the occurrence of cannabis use breaks (tolerance and other use breaks), or the duration of these breaks, is associated with changes in hazardous cannabis use (CUDIT-R), CUD severity, cannabis use frequency, and withdrawal symptoms over a 6-month follow-up. METHODS: Young adults, who recreationally use cannabis, (N=170, 55.9% female, Mean age=21 yo) completed baseline and on-time 6-month assessments of hazardous cannabis use (CUDIT-R), CUD severity, cannabis use frequency, and withdrawal symptoms. The occurrence of cannabis use breaks and the duration of these breaks during the intervening period was assessed at 6 months. RESULTS: Taking a T-break was associated with an increase in hazardous cannabis use and CUD severity at 6 months. When considering cannabis use breaks for other reasons, a longer break was associated with a significant decrease in hazardous cannabis use (CUDIT-R), CUD severity, and cannabis use frequency at 6 months. CONCLUSION: Findings from our study suggest recreational PUCs who take a T-break may be at greater risk for problematic cannabis use. In addition, taking a longer cannabis use break for other reasons may have beneficial effects on cannabis-related outcomes. The ability to abstain from cannabis for other reasons may be protective while individuals who take T-breaks may be important targets for intervention and prevention.

Associations between modes of cannabis use in daily life with concurrent and longitudinal hazardous use and consequences.

BACKGROUND: As diverse cannabis use patterns among recreational users continue to evolve, little is known about how modes of use may contribute to long-term risk. The current study examined the association between types and number of modes of cannabis used over a 21-day ecological momentary assessment (EMA) period with hazardous cannabis use and consequences both concurrently and six months later. METHODS: A sample of 155 young adult recreational cannabis users, aged 18-30 (M = 21.1), reported on cannabis use patterns over 21-days, and completed baseline and six-month assessments of hazardous cannabis use and cannabis consequences. RESULTS: At baseline, more frequent bowl use was associated with hazardous cannabis use and cannabis consequences. More frequent use of hash-oil was associated with more consequences at six months, while a greater proportion of hash-oil use relative to total use was associated with increased risk for hazardous cannabis use at six months. CONCLUSION: While bowl use is characteristic of concurrent problematic use and consequences, only hash-oil predicted increased risk for hazardous use and consequences later. It may be that more frequent use of high-potency cannabis products, such as hash-oil, present unique risks for cannabis problems and consequences.

The Effects of Alcohol and Cannabis Co-Use on Neurocognitive Function, Brain Structure, and Brain Function.

Purpose of review: Given increases in the rates of alcohol and cannabis co-use among adolescents and young adults, this review aims to summarize literature on the effects of alcohol and cannabis co-use on neurocognitive functioning, brain structure, and brain function. Recent findings: The limited existing studies examining concurrent, recent, and lifetime alcohol and cannabis co-use suggest effects on the brain are likely multifaceted. The majority of studies report that co-use is associated with negative outcomes such as impaired cognitive function and significant alterations in key structural and functional regions of the brain, while others report null effects of co-use compared to non-substance using control and single-substance use groups. Summary: Current studies lack a general consensus on methodology, definitions of concurrent and simultaneous use, and neuroimaging approaches, which makes it challenging to draw strong conclusions about the effects of co-use. More studies are needed to explore the effects of co-use in the context of simultaneous alcohol and cannabis use.

Cancer treatment effects on cognition and depression: The moderating role of physical activity.

OBJECTIVES: Breast cancer survivors report significant cognitive impairments post treatment, particularly following chemotherapy. Depression may also occur post treatment and may partially mediate the effects of cancer treatment on cognition. Additionally, physical activity has been shown to mitigate treatment effects on cognition and depression. This study examined the role of depression in mediating the effects of cancer treatment on cognitive function (perceived cognitive impairment, PCI; perceived cognitive ability, PCA) in breast cancer survivors and explored the role of physical activity in moderating these effects. MATERIALS AND METHODS: 317 breast cancer survivors were recruited via Army of Women. Participants were 40-75 years old and had stage 0 (in situ) to IIIc breast cancer and were less than 10 years post treatment. Participants completed a demographic and treatment questionnaire, as well as the International Physical Activity Questionnaire, Functional Assessment of Cancer Therapy-Cognitive Function, and Center for Epidemiologic Studies Depression Scale. RESULTS: Depressive symptoms significantly contributed to cognitive function in all models. Moderate and vigorous levels of physical activity moderated breast cancer treatment effects on depression and cognition. Chemotherapy, tamoxifen, and anastrozole all demonstrated negative effects on cognition. CONCLUSION: The results from this study support the importance of examining mediating factors in the effects of cancer treatment on cognition, particularly depression, following cancer treatment. Effects of treatment on cognition in breast cancer survivors are partially explained by changes in depressive symptoms, although chemotherapy may impact cognition independent of depression. Importantly, physical activity may reduce the risk of depression and cognitive impairment in breast cancer survivors.