But by no means is it benign and harmless to use, especially for young people who are still developing physically and emotionally.
I'm of the opinion that prolonged and chronic pot use severely slows development of social and cognitive skills.
Sometimes the caricatures are accurate...
Anyway, the preponderance of evidence suggests that it's best to keep a clear head and steer clear of mind-altering substances altogether, if you want to live a healthy and natural life. For medical purposes, of course, it's worth the risk.
Four lines of evidence all substantiate that marijuana is addictive: basic neuroscience, animal studies, clinical reports of human experience with marijuana, and epidemiology. Data from these four areas of scientific research corroborate each other and interweave fluidly to dispel the myth that marijuana is not addictive.
In order to place the following information in its proper perspective, medicine's current understanding of how marijuana interacts with the brain needs to be outlined. Scientific research has discovered an extensive system of nerves within the brain that communicate with each other using the same basic chemistry found in marijuana. The THC (tetrahydrocannabinol) and similar molecules in marijuana are able to affect the brain by mimicking our natural neurotransmitters and flooding receptor sites with stimulation. All the cannabinoid-based areas of the brain are subsequently activated beyond normal physiological levels by using marijuana.
While we are only beginning to unravel the pervasive role the endocannabinoid (i.e., the brain's naturally occurring THC-like molecules) system plays in overall brain function, Raphael Mechoulam, one of the most important pioneers in cannabinoid research, has declared that "The cannabinoid receptors are found in higher concentrations than any other receptor in the brain... and the endocannabinoid system acts essentially in just about every physiological system that people have looked into, so it appears to be a very central system."

2)
http://www.csam-asam.org/marijuanas-addictive-potential-healthcare-professionals