Recreational drugs can more than double risk of stroke, study suggests

Close up of ready to smoke cannabis

Recreational drugs can more than double the risk of stroke, with some of the most concerning impacts seen among younger people, a major review suggests.

Scientists analysed medical data from more than 100 million people and found that the risk of stroke was 122% higher for amphetamine users and 96% higher for cocaine users compared with those who did not take the drugs.

Cannabis users were also at greater risk, suffering 37% more strokes than non-users, the review found, though researchers saw no evidence that opioids, a highly addictive painkiller, added to a person’s risk of stroke.

The rise in strokes observed in connection with some drugs was not confined to older people. When researchers focused on under-55s, they saw a near tripling in stroke risk among amphetamine users. The additional risk linked to cannabis was a more modest 14% in the age group, while the risk from cocaine was much the same at 97%.

Strokes occur when blood vessels in the brain become blocked or burst. This disrupts the blood supply to brain cells, causing them to die. Stroke is the third leading cause of death and disability worldwide, leading to more than seven million deaths annually. Millions more are left with permanent disabilities, ranging from paralysis to speech and cognitive impairment.

The researchers pooled data from 32 studies on stroke and recreational drugs, involving more than 100 million people, to see which substances, if any, were associated with a greater risk. This revealed links between drug use and strokes, but it could not prove the drugs were to blame: drug users may simply be more prone to strokes for other reasons, such as poorer general health.

To delve deeper, the researchers ran more analyses to see if drugs were the probable cause of higher stroke risk. They looked at whether people who were genetically predisposed to having a drug disorder were more likely to suffer a stroke and found they were. The finding bolstered the suspicion that drugs were to blame, rather than drug users being at greater risk for other reasons. Details are published in the International Journal of Stroke.

The drugs appear to raise stroke risk in multiple ways. Amphetamines and cocaine can send blood pressure soaring, but also constrict blood vessels in the brain, potentially explaining why users are at greater risk of both bleeds and blockages in the brain. Cocaine also seems to accelerate atherosclerosis, where cholesterol, fat and other substances build up in arteries, causing them to harden and narrow. Cannabis constricts blood vessels too, and may exacerbate the problem by encouraging the formation of blood clots.

The findings are a concern as global recreational drug use has risen over the past decade. According to the UN, about 300 million people now consume illicit drugs regularly, with an estimated 228 million using cannabis, 30 million using amphetamines and 23 million using cocaine.

The Guardian