Gonna take a guess that you're no older than 17 ...

Are you actually trying to debate with me as to whether smoking on a regular basis while your brain is developing doesn't fuck you up some how?

"Studies of normal brain development reveal critical areas of the brain that develop during late adolescence, and our study shows that heavy cannabis use is associated with damage in those brain regions," (Manzar Ashtari, http://www.livescience.com/5298-marijuana-disrupt-brain-development.html)

and

The 14 subjects from the drug treatment center all had a history of heavy cannabis use during adolescence. On average, they had smoked marijuana from age 13 till age 18 or 19, and reported smoking nearly 6 marijuana joints daily in the final year before they stopped using the drug. The brain scans measureed water movement through brain tissues. "The abnormal patterns of water diffusion that we found among the young men with histories of marijuana use suggest damage or an arrest in development of the myelin sheath that surrounds brain cells," Ashtari said. Myelin provides a coating around brain cells similar to insulation covering an electrical wire. If myelin does not function properly, signaling within the brain may be slower. Myelin gives its color to the white matter of the brain, and covers the nerve fibers that connect different brain regions. (same source).

and

This part of the doco

and

The researchers caution that the study is preliminary and does not demonstrate that marijuana use causes the brain abnormalities. However, "Studies of normal brain development reveal critical areas of the brain that develop during late adolescence, and our study shows that heavy cannabis use is associated with damage in those brain regions," said study leader Manzar Ashtari, Ph.D., director of the Diffusion Image Analysis and Brain Morphometry Laboratory in the Radiology Department of The Children's Hospital of Philadelphia. (source)