Question: Is marijuana use associated with increased risk for stroke?

Context:
The illicit drugs more commonly associated with stroke are psychomotor stimulants, such as amphetamine and cocaine. Less commonly implicated are opioids and psychotomimetic drugs, including cannabis.
Among 326 patients (184 males), the most frequent stroke risk factors overall were dyslipidaemia (187), smoking (161), hypertension (105) and obesity (92). Fifty-one patients used illicit drugs, mostly comprising marijuana and amphetamines.
Patients in Adelaide are more likely to be obese, to be misusing marijuana and amphetamines, to suffer a cardioembolic event and to have a stroke that concurrently affects both the anterior and posterior cerebral circulation.
RCVS was spontaneous in 37% of patients and secondary in the 63% others, to postpartum in 5 and to exposure to various vasoactive substances in 37, mainly cannabis, selective serotonin-recapture inhibitors and nasal decongestants.
We reported two cases of young stroke associated with drug misuse. Case 1 used amphetamine, cocaine, marijuana and LSD for few yaers, and developed occlusion of a middle cerebral artery. Case 2 presented aphasia shortly after marijuana smoking.
Marijuana may have accelerated stroke onset, but essential cause of stroke in this case must be protein S mutation.
Cannabis is the most widely consumed among the illicit drugs worldwide, but it has only exceptionally been associated to cerebrovascular disease.
We here describe 2 young patients (26 and 29 years, respectively) who suffered from ischemic stroke in temporal relation with cannabis consumption.
The review of the literature on this topic reveals another 18 patients with stroke in association to cannabis use.
Although a causal relationship is difficult to establish due to the widespread use of cannabis, this drug may play an etiologic role in ischemic stroke.
Marijuana may trigger a myocardial infarction and have a vasospastic effect.
Despite the fact that cannabis is the most widely used illicit drug, there are only a few reports associating its use with cerebrovascular disease.
We describe a patient who suffered three ischaemic strokes immediately after cannabis consumption.
Cannabis use may be associated with ischaemic stroke in young patients, but its mechanism is unclear.
A right occipital ischemic stroke occurred in a 37-year-old Albanese man with a previously uneventful medical history, 15 min after having smoked a cigarette with approximately 250 mg of marijuana.
Therefore, as the family history for cerebrovascular events, blood pressure, clotting tests, examinations for thrombophilia, vasculitis, extracranial and intracranial arteries and cardiac investigations were normal or respectively negative, the stroke was attributed to the chronic cannabis consumption.
Three adolescent males had similar presentations of headache, fluctuating level of consciousness or lethargy, visual disturbance, and variable ataxia after self-administration of marijuana.
Episodic marijuana use may represent a risk factor for stroke in childhood, particularly in the posterior circulation.
Although several mechanisms exist by which marijuana use might contribute to the development of chronic cardiovascular conditions or acutely trigger cardiovascular events, there are few data regarding marijuana/THC use and cardiovascular disease outcomes.
Reported here is the case of a previously healthy young man who smoked marijuana on a daily basis and had an occipital lobe stroke; he was found to be heterozygous for factor V Leiden.
This case suggests that marijuana smoking may increase the risk of arterial thrombosis in otherwise healthy individuals who are heterozygous for factor V Leiden.
Thus, chronic abuse of marijuana might be a risk factor for stroke.
A 22-year-old man with a five-year history of drug and alcohol abuse presented with a left hemiparesis preceded by three transient ischaemic attacks, two of which occurred whilst smoking cannabis. Substance abuse was the only identifiable risk factor for cerebrovascular disease.
Chronic marijuana smoking, however, seems to reduce CBF.
Research directions might include more studies of cardiovascular disease outcomes and relationships of marijuana with cardiovascular risk factors, studies of metabolic and physiologic effects of chronic marijuana use that may affect cardiovascular disease risk, increased understanding of the role of the cannabinoid receptor system in cardiovascular regulation, and studies to determine if there is a therapeutic role for cannabinoids in blood pressure control or for neuroprotection after stroke.

Answer: Yes, the use of marijuana is associated with increased risk for ischemic stroke, especially in young adults. The mechanisms underlying such association remain largely unclear, but increased vascular reactivity and increased cerebrovascular resistance were implicated.
Exact answer: yes