Lack of evidence for the effectiveness or safety of over-the-counter cannabidiol products

Abstract

Over the past 5 years, public interest in the potential health benefits of cannabidiol (CBD) has increased exponentially, and a wide range of over-the-counter (OTC) preparations of CBD are now available. A substantial proportion of the population appears to have used these products, yet the extent to which they are effective or safe is unclear. We reviewed the evidence for whether CBD has significant pharmacological and symptomatic effects at the doses typically found in OTC preparations. We found that most of the evidence for beneficial effects is derived from studies of pure, pharmaceutical grade CBD at relatively high doses. Relatively few studies have examined the effect of OTC CBD preparations, or of CBD at low doses. Thus, at present, there is little evidence that OTC CBD products have health benefits, and their safety has not been investigated. Controlled trials of OTC and low-dose CBD preparations are needed to resolve these issues.

Individual and combined effects of Cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC) on striato-cortical connectivity in the human brain

“…This study showed increased connectivity within the executive control network; usually conceived as a network subserving attentional and cognitive processes involved in task engagement. Cannabidiol also may be a negative allosteric modulator at CB1 receptors (Laprairie et al, 2015;Chesney et al, 2020), and here we show increases in connectivity in the associative striatum; the region of the striatum most associated with cognitive functions and brain regions.…”

“…THC is thought to exert its effects primarily by partial agonism at the CB1 receptor (Pertwee, 2008). CBD has less well understood and more complex pharmacological effects, including negative allosteric modulation at the CB1 receptor (Chesney et al, 2020), reducing reuptake of anandamide, and action on GPR55, μ-opioid, and 5-HT1A receptors (Pertwee, 2008). CBD has antipsychotic, (Leweke et al, 2012; McGuire et al, 2018), anxiolytic (Bergamaschi et al, 2011a) and anti-addictive (Hindocha et al, 2018; Hurd et al, 2019; Freeman et al, 2020) properties, and therefore has broadly oppositional neuropsychopharmacological effects to THC (Curran et al, 2016; Gunasekera et al, 2020).…”

Opportunities, Challenges and Pitfalls of Using Cannabidiol as an Adjuvant Drug in COVID-19

“…In addition, careful examination of whether the influence of CBD on the immune system could exacerbate viral infection is required (reviews [ 64 , 65 ]). Indeed, viral, fungal infections and pneumonia infections are listed among the side effects of CBD [ 166 , 167 , 168 , 169 ]. Moreover, it has to be considered that CBD, which was found to have a pro-oxidative effect in one preclinical study ([ 83 ]; Table 1 ), might even aggravate the feared cytokine storm.…”

“…Unfortunately, these products may be of questionable quality, are not subject to appropriate safety controls and are characterized by unknown CBD content. There is little evidence of the pharmacological activity or health benefits of non-commercial CBD preparations [ 54 , 167 ]. Importantly, people taking non-commercial preparations on their own should be very careful due to the possibility of dangerous consequences, such as respiratory depression following, for example, CBD gummy ingestion [ 170 ] or CBD oil overdose [ 171 ].…”

“…However, the authors of the latter two reviews postulated the need to conduct additional clinical trials. Indeed, various side effects of CBD have recently been described [ 166 , 167 , 168 , 169 ]. In addition to the increased risk of infection mentioned above, the increased tendency for respiratory depression and aspiration to occur, that is, symptoms also occurring in COVID-19, should be considered.…”