For the typical brain, LSD is safe, but some people have a different reaction. Not everyone reacts the same way. As I said, more research is needed before we can estimate with confidence what these risks and population curves are. Some people are destined to become schizophrenics without using LSD, some are bound to be borderliners. We do not know.
More research is needed.
Beside the medical benefits for seriously ill people, it is much better to relax with a joint after work than to go get tanked at the local pub. If it were actually 'legalized' as opposed to 'decriminalized' it would be a valuable form of tax revenue. Of course in excess it can lead to some pretty serious lack of motivation. Hard drugs such as speed, XTC, PCP, Her-on, coke, etc truly are for the experimental individual. However these drugs DO ruin a vast amount of lives.