Maybe that's why they're so depressed and frustrated -- they're not getting enough play, booze, and weed... Prozac and Xanax under a shrink's supervision compare poorly to raging parties fueled by good drugs and strong booze.

BTW - a lot of the stats are skewed by changing norms. Alcohol was legal for over-18s (HS seniors) in some states until the mid-80s, thus it wasn't an illicit substance. Getting married at 18 and making a kid by 19 was a lot more common and accepted in 1950-1960 than it is now.