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Marijuana use affects blood flow in brain even after abstinence

People who smoked marijuana had changes in the blood flow in their brains even after a month of not smoking, according to a study published in the February 8 issue of Neurology, the scientific journal of the American Academy of Neurology.

The findings could explain in part the problems with thinking or remembering found in other studies of marijuana users, according to study authors Ronald Herning, PhD, and Jean Lud Cadet, MD, of the National Institute on Drug Abuse in Baltimore, Md.

The study involved 54 marijuana users and 18 control subjects. The marijuana users volunteered to take part in a month-long inpatient program. The blood flow velocity in brain arteries was tested with transcranial Doppler sonography in all participants at the beginning of the study and again at the end of the month for the marijuana users.

The blood flow velocity was significantly higher in the marijuana users than in the control subjects, both at the beginning of the study and after a month of abstinence from marijuana use. The marijuana users also had higher values on the pulsatility index (PI), which measures the amount of resistance to blood flow. This is thought to be due to narrowing of the blood vessels that occurs when the circulation system’s ability to regulate itself is impaired.

Marilee Reu | EurekAlert!
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