Cannabis can affect blood flow in the brain. According to a study by researchers at the US National Institute on Drug Abuse these effects can last more than one month in cases of large consumers. The authors say in the journal Neurology that “these findings may provide us with a partial explanation for the cognitive deficits observed in a similar group of marijuana users. ”
They measured cerebral blood flow in 54 marijuana smokers, light smokers, defined as those who consumed an average of 11 joints a week, moderate who came to 44, and large consumers with an average of 131 per week. Cannabis smokers had a greater cerebral blood flow than nonsmokers. The resistance to blood flow was also greater.
The measurement was repeated after one month after cessation of cannabis. At that time the resistance to blood flow of light and moderate consumers begins to return to normal, while still in increase in large consumers.
Studies have shown in recent years that cognitive deficits that occur in cannabis users back to normal last few days or weeks after leaving consumption, although such standards may require more than one month in heavy users.