The stereotypical “lazy stoner” has been a staple of modern culture for decades. It is only now, however, that researchers have confirmed that the drug negatively impacts the brain’s ability to produce dopamine – the chemical responsible for promoting motivation in humans.
The study, funded by the Medical Research Council and published in the journal Biological Psychiatry, involved taking PET scans of 19 cannabis users and 19 non-users. In each subject’s case, researchers measured the brain’s output of Dopamine. The weed user’s brains showed a consistently lower output of Dopamine than the non-user’s brains.
The cannabis users with the lowest levels of Dopamine production were those that qualified as marijuana abusers, as well as those who started using the drug in their pre-teen and early-teen years.
Previous studies on the effects of marijuana on human brains have shown that the drug has little or no effect on Dopamine output. This study, which only tested marijuana users which have also suffered schizophrenic episodes, may prove to be inaccurate.
Michael Bloomfield, the man leading the study, was actually surprised by his findings which go against previous study’s results. He did say, however, that these results, “tie in with previous research on addiction, which has found that substance abusers – people who are dependent on cocaine or amphetamine, for example – have altered dopamine systems.”
More research will be necessary to conclude the effects of marijuana use on the human brain. If nothing else, this study opens the door for more exploration on the drug’s potential for harm.