“There is a long history of informal use of Cannabis sativa (commonly called cannabis) for many purposes, including treating various ailments worldwide. However, the legalization of cannabis in multiple countries, specifically for medical purposes, has grabbed the researchers’ attention to discover the scientific evidence of cannabis’s beneficial effects. Among over 500 identified compounds (cannabinoids), Δ9-Tetrahydrocannabinol (THC) and cannabidiol (CBD) are two major active cannabinoids derived from cannabis. Cannabinoids exert their effects through cannabinoid receptors (CB1R and CB2R). In the recent past, clinical trials have shown the efficacy of cannabis and cannabinoids for various human ailments such as cancer, neurological disorders, inflammatory bowel disease, chronic pain, and metabolic disorders. The commonly used constituents and derivatives of cannabis include CBD, THC, THCV, dronabinol, nabilone, and nabiximol. The cannabis constituents have also been used in combination with other agents such as megestrol acetate in some clinical trials. The common routes for the administration of cannabis are oral, sublingual, or topical. Cannabis has also been consumed through smoking, inhalation, or with food and tea. As high as 572 patients and as low as nine patients have participated in a single clinical trial. Cannabis is legalized in some countries with restrictions, such as Belize, Canada, Colombia, Costa Rica, The Czech Republic, Jamaica, Netherlands, South Africa, Spain, and Uruguay. This article provides a compilation of published studies focusing on clinal trials on the therapeutic effects of cannabis. The adverse effects of cannabis and its constituents are also discussed.”

https://pubmed.ncbi.nlm.nih.gov/35619266/

https://www.eurekaselect.com/article/123960

“Introduction: A relationship between tobacco smoking and hearing loss has been reported; associations with cannabis smoking are unknown. In this cross-sectional population-based study, we examined relationships between hearing loss and smoking (tobacco, cannabis, or co-drug use).

Methods: We explored the relationship between hearing loss and smoking among 2705 participants [mean age = 39.41 (SE: 0.36) years] in the National Health and Nutrition Examination Survey (2011 to 12; 2015 to 16). Smoking status was obtained via questionnaire; four mutually exclusive groups were defined: nonsmokers, current regular cannabis smokers, current regular tobacco smokers, and co-drug users. Hearing sensitivity (0.5 to 8 kHz) was assessed, and two puretone averages (PTAs) computed: low- (PTA0.5,1,2) and high-frequency (PTA3,4,6,8). We defined hearing loss as threshold >15 dB HL. Multivariable logistic regression was used to examine sex-specific associations between smoking and hearing loss in the poorer ear (selected based on PTA0.5,1,2) adjusting for age, sex, race/ethnicity, hypertension, diabetes, education, and noise exposure with sample weights applied.

Results: In the age-sex adjusted model, tobacco smokers had increased odds of low- and high-frequency hearing loss compared with non-smokers [odds ratio (OR) = 1.58, 95% confidence ratio (CI): 1.05 to 2.37 and OR = 1.97, 95% CI: 1.58 to 2.45, respectively]. Co-drug users also had greater odds of low- and high-frequency hearing loss [OR = 2.07, 95% CI: 1.10 to 3.91 and OR = 2.24, 95% CI: 1.27 to 3.96, respectively]. In the fully adjusted multivariable model, compared with non-smokers, tobacco smokers had greater odds of high-frequency hearing loss [multivariable adjusted odds ratio = 1.64, 95% CI: 1.28-2.09]. However, in the fully adjusted model, there were no statistically significant relationships between hearing loss (PTA0.5,1,2 or PTA3,4,6,8) and cannabis smoking or co-drug use.

Discussion: Cannabis smoking without concomitant tobacco consumption is not associated with hearing loss. However, sole use of cannabis was relatively rare and the prevalence of hearing loss in this population was low, limiting generalizability of the results. This study suggests that tobacco smoking may be a risk factor for hearing loss but does not support an association between hearing loss and cannabis smoking. More definitive evidence could be derived using physiological measures of auditory function in smokers and from longitudinal studies.”

https://pubmed.ncbi.nlm.nih.gov/35383601/

https://journals.lww.com/ear-hearing/Abstract/9900/Tobacco,_but_Neither_Cannabis_Smoking_Nor_Co_Drug.3.aspx

“Objective: The aim of this paper is to demonstrate the impact of heavy and chronic cannabis use on brain potential functional control, reorganization, and plasticity in the cortical area.

Methods: 23 cannabis users were convened in 3 user’s groups. The first group included 11 volunteers with an average of 15 joins/day; the second group included 6 volunteers with an average of 1.5 joins/day; the third group included 6 volunteers with an average of 2.8 joins/week. Besides, a 6 healthy volunteers (control group). All healthy and cannabis users underwent identical brain BOLD-fMRI assessment of the motor function. Besides, neuropsychological and full biological assessments were achieved.

Results: BOLD-fMRI maps of motor areas were obtained, including quantitative evaluation of the activations in the motor area. Besides, statistical analysis of various groups was achieved.

Conclusion: Chronic cannabis addiction of varying use strength by groups of heavy, moderate, low dose, and zero doses are shown to have systematically equivalent effects on the control of brain motor function. Indeed, the BOLD-fMRI shows a remarkable sensitivity to minimal brain plasticity and reorganization of the functional motor control of the studied cortical area, and such varionation was not shown. Specific elucidation of the cannabis effect mechanisms in this unique function should clarify further protective pharmacological effects. This might illuminate the use of neuronal resources to prepare processes for pharmacological use and pharmaceutical forms. This suggests exploring any potential cannabis pharmaceutical form in diseases involving motor impairments.”

https://pubmed.ncbi.nlm.nih.gov/35578884/

https://www.eurekaselect.com/article/123583

“Previous investigators have found no clear relationship between specific blood concentrations of ∆⁹-tetrahydrocannabinol (∆⁹-THC) and impairment, and thus no scientific justification for use of legal “per se” ∆⁹-THC blood concentration limits. Analyzing blood from 30 subjects showed ∆⁹-THC concentrations that exceeded 5 ng/mL in 16 of the 30 subjects following a 12-h period of abstinence in the absence of any impairment. In blood and exhaled breath samples collected from a group of 34 subjects at baseline prior to smoking, increasing breath ∆⁹-THC levels were correlated with increasing blood levels (P < 0.0001) in the absence of impairment, suggesting that single measurements of ∆⁹-THC in breath, as in blood, are not related to impairment. When post-smoking duration of impairment was compared to baseline ∆⁹-THC blood concentrations, subjects with the highest baseline ∆⁹-THC levels tended to have the shortest duration of impairment. It was further shown that subjects with the shortest duration of impairment also had the lowest incidence of horizontal gaze nystagmus at 3 h post-smoking compared to subjects with the longest duration of impairment (P < 0.05). Finally, analysis of breath samples from a group of 44 subjects revealed the presence of transient cannabinoids such as cannabigerol, cannabichromene, and ∆⁹-tetrahydrocannabivarin during the peak impairment window, suggesting that these compounds may be key indicators of recent cannabis use through inhalation. In conclusion, these results provide further evidence that single measurements of ∆⁹-THC in blood, and now in exhaled breath, do not correlate with impairment following inhalation, and that other cannabinoids may be key indicators of recent cannabis inhalation.”

https://pubmed.ncbi.nlm.nih.gov/35585089/

“In conclusion, we present further evidence that single measurements of ∆⁹-THC in blood cannot establish impairment, that single measurements of ∆⁹-THC in exhaled breath likewise do not correlate with impairment, and that ∆⁹-THCV and CBC may be key indicators of recent cannabis use through inhalation within the impairment window.”

https://www.nature.com/articles/s41598-022-11481-5