Studies related to Cerebral Blood Flow and Marijuana

Postural Syncope After Marijuana: A Transcranial Doppler Study Of The Hemodynamics

Effect Decrease
Trial Design Double blind
Trial Length 24 hours
Number of Subjects 29
Gender Both Genders
Age Range 18-29, 30-44
Notes for this study:
Administration of marijuana (as inhalant), relative to placebo, was associated with some subjects experiencing orthostatic symptoms (28% of the study) and in these persons symptoms peaked immediately after inhalation and was associated with a drop in cerebral blood flow.

Middle Cerebral Artery Velocity During Upright Posture After Marijuana Smoking

Effect Decrease
Trial Design Double blind
Trial Length 24 hours
Number of Subjects 10
Gender Male
Age Range 18-29, 30-44
Body Types Average
Notes for this study:
In 10 drug-free men who were subject to either a joint or placebo joint, inhalation of marijuana was associated with development of orthostatic hypotension in some subjects which appeared to be related to a decrease in blood pressure (in all cases of orthostatic hypotension) and reduction in peripheral blood pressure (in the more extreme cases).

Regional Cerebral Blood Flow After Marijuana Smoking

Effect Increase
Trial Design Double blind
Trial Length 24 hours
Number of Subjects 20
Gender Male
Age Range 18-29
Body Types Average
Notes for this study:
Acute inhalation of two doses of marijuana (1.75% THC cigarette or 3.55%) appeared to increase global cerebral blood flow in both hemispheres when tested after 30-60 minutes, but not after 120 minutes. These changes were associated with an increase in tension/anger, intoxication, but no significant differences in blood pressure noted.

Placebo cigarettes were used in this study, and while the study was acute in nature it was conducted in persons with a history of marijuana usage who did not consume any two weeks prior to the study.