Recreational pot can have permanent impact on the brain

Even recreational use of marijuana can have a permanent impact on the brain. 

Researchers at Northwestern University studied the brains of 40 young adults, half of whom smoked marijuana casually.
They found the marijuana users had major differences in their brains, when compared to those who never used the drug. 

The regions related to emotion and motivation were altered, and the more marijuana a participant used, the more detrimental the effect.
They did not look at how these brain changes impacted their ability to function.
The changes were noticeable in participants who only used marijuana once or twice a week. 

Courtesy: NBC News Channel