What is being called the largest study on brain imaging ever done has made some troubling consequences of heavy cannabis consumption.
A group of researches from Amen Clinic, Google, John's Hopkins University, University of California, Los Angeles and the University of California, San Francisco investigated 62,454 single-photon emission computed tomography (SPECT) brain scans taken from over 30,000 people to find out what speeds up brain aging. As a person ages, blood flow to the brain is restricted and certain medical conditions and habits can further reduce blood flow.
The top cause of brain aging was schizophrenia, which on average added four years to a person's brain age. Other medical conditions also ranked high on the list with bipolar disorder adding an average 1.6 years and ADHD adding 1.4. However, drug abuse also weighed heavily on a person's brain age with cannabis use disorder adding 2.8 years and alcoholism adding 0.6.
"Based on one of the largest brain imaging studies ever done, we can now track common disorders and behaviors that prematurely age the brain," said the study's lead author, Daniel G. Amen in a statement. "Better treatment of these disorders can slow or even halt the process of brain aging. The cannabis abuse finding was especially important, as our culture is starting to see marijuana as an innocuous substance. This study should give us pause about it."