Marijuana and alcohol abuse cause premature brain ageing

According to a new study by researchers in the US, smoking marijuana causes the brain to age on average by 2.8 years. The study also found that alcohol abuse caused accelerated ageing in the brain.  While the impact was not as severe as for marijuana use, alcohol use appeared to cause the brain to age on average by 0.6 years. The researchers defined brain ageing as the decreased level of blood flowing through the brain.

The study also found that three types of brain disorders lead to premature ageing of the brain. People with schizophrenia showed an average of 4 years of premature brain ageing, while the comparable numbers for people who have bipolar disorder and attention-deficit/hyperactivity disorder were 1.6 years and 1.4 years respectively.

The study was conducted by a team of researchers from Amen Clinics (Costa Mesa, California), Google (Mountain View, California), Johns Hopkins University (Baltimore, Maryland) and the University of California (San Francisco and Los Angeles, California). The research team evaluated 62,454 brain scans taken from 31,227 individuals between the ages of nine months and 105 years during both resting and active brain activity. This was most likely the largest study of brain imaging ever undertaken.

Commenting on the study, Dr Daniel Amen, the study’s lead author and founder of Amen Clinics, said he thought the findings on marijuana abuse were “especially important” because marijuana is now more often seen as being an “innocuous substance” and that the results of this research “should give us pause” about that assumption.