I have written previously about some of the medicinal effects of the CBD (cannabinoid) component of marijuana. Despite the fact that cannabis is legal in most states of America and perceived to be harmless for recreational use, newer evidence has emerged showing that regular heavy use of cannabis causes a number of adverse health effects. Furthermore, it triggers cardiovascular complications of various types, and has even caused death, in young people.
THC (psychoactive) versus the CBD (medicinal) portions of marijuana (cannabis)
Delta 9-tetrahydrocannabinol (THC) is the psychoactive substance that is produced from marijuana. Its use for relaxation and euphoria is becoming more widespread since the decriminalization and legalization of cannabis began with Uruguay in 2012. This was done to replace links of organized crime to cannabis trade, with state regulation to allow for accountable and safe sale and distribution. Soon after this, Washington and Colorado States led the U.S. movement to legalize recreational cannabis. Yet its adverse effects are not being told.
Cardiovascular risk with marijuana use
Case reports of acute coronary syndrome (heart attack) and cerebrovascular episodesd (stroke) have been reported from marijuana use. When this occurs, it is more likely to occur during the first hour after marijuana inhalation.  Moreover, marijuana can aggravate heart vessel ischemia in patients with known coronary artery disease, potentially triggering a myocardial infarction. This is partially explained by the fact that there are endocannabinoid receptors in the heart.
Case studies can be illustrative. One case series identified three young patients in which marijuana use appeared to be the only cause of cardiac arrest. One of these patients was found collapsed at home in asystole (heart not pumping) and was resuscitated and taken to coronary angiography which showed a pronounced and diffuse arterial vasospasm. Two other patients were found to have occlusion of a coronary artery which caused ventricula