Harmful Effects of Smoking Cannabis : A Cerebrovascular and Neurological Perspective
Sabrina Rahman Archie and Luca Cucullo
Frontiers in Pharmacology, 2019, 10, Article 1481.
doi : 10.3389/fphar.2019.01481
Apart from being used as a medicine, cannabis or marijuana is the most widely abused recreational drug all over the world. The legalization and decriminalization of cannabis in Canada and various states of USA may be the underlying reason of the widespread popularity of it among young population. Various studies have reported about the relationship between cannabis use and different detrimental effects like cardiovascular, cerebrovascular, and neurological complications among different age groups. Specifically, the young population is getting adversely affected by this, harmful yet, readily accessible
recreational drug. Although the mechanism behind cannabis mediated neurological and cerebrovascular complications has not been elucidated yet, the results of these studies have confirmed the association of these diseases with cannabis. Given the lack of comprehensive study relating these harmful complications with cannabis use, the aim of this narrative literature review article is to evaluate and summarize current studies on cannabis consumption and cerebrovascular/neurological diseases along with the leading toxicological mechanisms.
Keywords : oxidative stress, cannabis, recreational, drug, abuse, cerebrovascular, neurodegenerative, stroke
Cannabis, commonly termed as marijuana, weed, pot, and ganja, is the most widely used illicit recreational drug around theworld (Thomas et al., 2014;Wolff and Jouanjus, 2017). It is extracted from the natural plant Cannabis sativa and amongmore than 60 cannabinoids, tetrahydrocannabinol is one of the major active ingredients of cannabis (Atakan, 2012). In addition to the natural source, the use of synthetic cannabis (SC) named as spice, K2 or Kronic has gained popularity during the last decade (Wolff and Jouanjus, 2017). In spite of using cannabis in medicinal purposes as antioxidant, anti-convulsant, anti-inflammatory, and neuroprotective, the detrimental effects of it cannot be denied (Ford et al., 2017). Acute and chronic use of cannabis is associated with different harmful effects on central nervous system and peripheral system including hyperemesis syndrome, impaired coordination and performance, anxiety, suicidal/tendencies, psychotic symptoms andmood disorders, cannabis withdrawal symptoms, exacerbation of psychotic disorders, neurocognitive impairment, cardiovascular, neurological, respiratory, cerebrovascular, peripheral vascular diseases (Thomas et al., 2014; Karila et al., 2014), pneumo-mediastinum, pneumothorax, pneumo-pericardium, bullous lung, disease, increased risk of chronic obstructive pulmonary disease, desquamated interstitial disease, and appearance of brown pigmented macrophages (Milroy and Parai, 2011).
Despite having serious effects of marijuana in human health, its use has been legalized in Canada and different states of USA. The Canadian Parliament passed Bill C-45, the Cannabis Act to legalize and regulate the production, distribution, and consumption of cannabis on June 19, 2018, and its legalization started effective from October 17, 2018 (Crepault, 2018). In case of US, marijuana use has been approved in 34 states for medical purposes (State Medical Marijuana Laws, 2019) and in 10 states for recreational purposes (Marijuana Overview, 2019).
Even though cannabis has medicinal benefit, recent studies have shown that chronic cannabis inhalation may be associated with cerebrovascular disease such as ischemic stroke (Thanvi and Treadwell, 2009) although the underlying mechanism between stroke and cannabis use has not been strongly established yet. Moreover, the hemorrhagic stroke occurrence has been rarely reported in different studies (Goyal et al., 2017). Several neurological disorders such as cognitive dysfunction, behavioral problems, memory, attention deficiency, structural, and functional changes in brain have been observed in different studies related to cannabis exposure (Chadwick et al., 2013; Battistella et al., 2014; Broyd et al., 2016; Szutorisz and Hurd, 2018). Increased use of cannabis or cannabinoids is associated with several complications related to different organs including the neurological and cerebrovascular system in human body. Due to this, exhaustive studies need to be performed to establish the possible link between cannabis inhalation and neurological and cerebrovascular effect. Keeping the popularity of cannabis use in mind, the aim of this review article is to list the neurological and cerebrovascular effects of marijuana inhalation including the probable mechanisms related to these effects.
Three biomedical literature databases, PubMed, Google Scholar, and ScienceDirect were searched up to July 2019. The search was conducted using “cannabis,” “cannabinoid,” “cannabidiol,” “delta- 9-THC,” “endocannabinoids,” “CB1 receptor,” “CB2 receptor,” “cerebrovascular system,” “Blood Brain Barrier,” “stroke,” “neurological disease,” “neuroprotective effect,” “oxidative stress.”
Articles dealing with medical use of cannabis were excluded as the aim of our review article is based on harmful effects of cannabis inhalation on cerebrovascular and neurological system. Case reports based on cannabis inhalation and cerebrovascular diseases were also searched and evaluated for inclusion in this review. Peer-reviewed articles presenting results of experimental studies in animal models and population-based studies were analyzed and presented in this review paper.