The damaged people might be due to more factors than the drug. Besides possible use amphetamines or other drugs, too, your experimental pool would only consist of those who would choose to use these drugs a lot for lengths of time and advertise this. There are some decent studies on use of peyote and ayahuasca where participants use it weekly or more for many years. They scored the same on physical well being but scored higher than the control for mental well being.
BTW, I totally agree that the term 'geek wonder drug' is inappropriate.