Can smoking cannabis damage your brain functions permanently?

Cannabis: Recent studies have shown that heavy smokers in adolescence have smaller brains than their peers. They also show compromise in higher cortical function and handling complex mental tasks.

Yes: There is a growing body of research about cannabis use and brain issues. Limbic system damage, psychosis, poor impulse control, addiction, and of course cross addictions are quite common and all brain issues. The younger you started using the worse the effects become.