DEAR DOCTORS: I am experiencing extreme headaches about 15 minutes after smoking cannabis. It used to happen occasionally, but now it’s every time. The migraine, which is very intense, goes away after about 30 minutes. Can you help me understand this?
DEAR READER: The specifics of your question fall outside of our normal practice. However, we were able to consult with colleagues here at UCLA who are experts in the area of headache and migraine. They pointed us to a phenomenon known as reversible cerebral vasoconstriction syndrome, or RCVS, which causes the symptoms you have described. Primary among them is the sudden onset of a severe and debilitating headache. Due to the speed with which it reaches peak intensity, this is referred to as a “thunderclap headache”. Additional symptoms can include nausea, vomiting, sensitivity to light, blurred vision, muscle weakness…
