Can Marijuana Use Cause Unilateral Weakness?
Marijuana use is not documented to directly cause unilateral weakness based on available clinical evidence. The provided guidelines and research do not identify focal neurological deficits like unilateral weakness as a recognized adverse effect of cannabis use.
Known Neurological Effects of Cannabis
The documented neurological effects of cannabis are primarily related to:
- Acute cognitive impairment including mental slowness, impaired reaction times, and memory disruption during intoxication 1, 2
- Psychomotor effects affecting coordination and reaction time, which can impair driving ability 1, 2
- Central nervous system adverse events that are generalized rather than focal, including dizziness, somnolence, and sedation 3, 4
Cardiovascular Considerations
While cannabis does not directly cause unilateral weakness, there are important cardiovascular risks that could theoretically lead to stroke-related weakness:
- Acute cardiovascular events including myocardial ischemia or infarction have been associated with cannabis toxicity, particularly in older adults 5, 6
- Increased risk of stroke has been documented as a cardiovascular adverse event associated with cannabis consumption 6
Critical clinical caveat: If a patient presents with unilateral weakness and recent cannabis use, you must urgently evaluate for stroke or other acute neurological emergencies rather than attributing the symptom to cannabis itself. The weakness would be from a vascular event potentially triggered by cannabis-induced cardiovascular effects, not from direct cannabis neurotoxicity.
Documented Neuropsychiatric Effects
The well-established neurological effects of cannabis are non-focal and include:
- Psychotic symptoms including hallucinations and delusions, particularly with high-THC products 5, 3
- Cognitive impairment affecting learning and memory, especially concerning in adolescents 3, 4
- Psychiatric destabilization including anxiety, depression, and exacerbation of underlying mental health conditions 5, 4
Clinical Approach
When evaluating unilateral weakness in a cannabis user:
- Immediately assess for stroke, transient ischemic attack, or other focal neurological pathology using standard neurological emergency protocols
- Consider cannabis as a potential cardiovascular risk factor that may have precipitated a vascular event 6
- Do not delay definitive neurological workup by attributing focal deficits to cannabis intoxication alone
- Remember that cannabis causes generalized CNS depression and coordination problems, not focal motor deficits 2, 4
The absence of unilateral weakness in comprehensive reviews of cannabis adverse effects 1, 3, 4 strongly suggests this is not a direct effect of the drug. Any focal neurological finding warrants immediate evaluation for structural or vascular pathology.