re: SIGH... rubbish...
I so agree R.L. People confuse long-term drug effects with the basic fact that the people that show permanently decreased functionality may very well have suffered that same fate without the drugs. Human beings often times have an internal makeup that's a timebomb waiting to go off. If it wasn't the pot they smoke, they'd find any excuse to sabotage their lives. They may choose a different tool like financial immaturity, ruining their lives in a sea of credit problems. They may let their health go.
I also know shining examples on both sides of the issue and in most cases my pot-smoking associates are the ones I'd trust the most in a crisis. There are far worse dangers in this world.