The active ingredient in marijuana, THC, affects different regions of the brain, according to a study out of Western University in Ontario. This may explain why not everyone who uses marijuana experiences the same effects.
Researchers say some people experience very rewarding effects that may lead to their becoming dependent on it. Others may feel negative psychiatric side effects such as paranoia, cognitive problems or an increased risk of developing schizophrenia.
The research on rats also found THC was able to strongly increase the addictive properties of opioid drugs like morphine.
Results suggest that the differing effects of THC may be due to genetic variations in the areas of the brain.
The study was published in Scientific Reports.