Illicit Drug Use and the Risk of Stroke

Author: Dr Nicolas Martinez-Majander

Affiliation: Department of Neurology, Helsinki University Hospital, Finland


Illicit drug use covers prohibited use of illegal drugs and inappropriate use of pharmaceutical drugs or other substances, such as certain inhalants. In Europe during 2017 up to 7% of inhabitants 15 years or older had used cannabis and 1% had used cocaine (European Monitoring Centre for Drugs and Drug Addiction). The majority of people with a drug use disorder worldwide are young, with one fourth being under-aged individuals.

Illicit drug use appears an important cause of stroke in geographic regions where their use is frequent, especially in the young. Not only may substances themselves increase the risk, but injection drug use may also cause infections (septicaemia, hepatitis B and hepatitis C, HIV, and endocarditis), which, in turn, can cause both ischemic and hemorrhagic stroke. In a large multicentre study conducted in the Baltimore-Washington area, recent use of illicit drugs was reported in 12.1% and illicit drug use appeared as a probable cause in 4.7% of their stroke cases.1


Cannabis is the most widely used illicit drug and a frequent use of it may increase the risk of stroke substantially. Although cannabis has been identified as an independent risk factor for ischemic stroke in some studies,2 it is difficult to know whether this a true independent effect or a reflection of confounding factors such as smoking.3

Amphetamine and related substances

Amphetamine-like substances can be used as central nervous system stimulants and appetite suppressors. The use of amphetamine may come with a 5-fold increase in the risk of stroke, both ischemic and hemorrhagic.4 The pathophysiology include e.g. acute hypertensive crisis, or platelet activation and aggregation with thrombus formation.


Cocaine is the second-most commonly used illicit drug after marijuana and also the most common one associated with stroke. It can be used as a central nervous system stimulant, vasoconstrictor, and local anaesthetic. There is evidence that the use of cocaine within the last 24 hours is strongly associated with an increased risk of stroke, especially with the crack cocaine (OR 7.9; 95% CI, 1.8-35.0).5 Frequent use (more than once a week) may increase the risk 2-fold also after excluding acute users. Again, possible mechanisms causing stroke include acute hypertensive crisis or platelet activation and aggregation, as well as infections leading to endocarditis and secondary vasculitis.6


Most strokes caused by heroin, derived from opium, are ischemic. Heroin can be injected intravenously or subcutaneously, snorted, or smoked. The first heroin related ischemic strokes were described in nine young heroin addicts in 1976.7 There are most likely differences in the stroke risk depending on route and timing of administration. However, so far there is no systematic population-based data available on the strength of association between heroin use and the risk of stroke.

In conclusion, the association between illicit drugs and stroke is supported by several studies and reviews, and should always be kept in mind when seeing patients in the emergency department and also in the diagnostic work-up of stroke patients.




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