Reality might have a little different shape for people who smoke lots of marijuana.

So it’s not a stretch to imagine that their brains might be shaped differently, too, as Australian scientists have recently reported.

Researchers used high-resolution M-R-I to compare the brains of chronic marijuana smokers with those of non-smokers.

Please note that the marijuana smokers in the study were of the variety that inhales… and then some.

Fifteen men who smoked more than five joints daily for more than ten years had their brains imaged. Do the math, and each of the men burned through more than eighteen-thousand marijuana cigarettes.

The study… published in the Archives of General Psychiatry… reported some striking changes in brain architecture among the marijuana users.

The hippocampus… a region of the brain believed to regulate emotion and memory… shrunk like a pair of jeans in the dryer. They were on average twelve percent smaller in the heavy marijuana smokers.

Another important brain structure called the amygdala [ah-mig-da-la], thought to play a role in fear and aggression, tended to be about seven percent smaller in pot smokers.

Experiments that measure brain anatomy in smokers and nonsmokers over time may one day allow scientists to get a more accurate picture of the physical effects.

However, the anatomical findings in this small M-R-I study challenge the opinion that marijuana has little effect on the brain, especially in long-term users.

That alone could be enough to make some people shrink from the smoking habit.