The thing is, no one knows what makes it work. Some believe its a push-pull effect from all the different herbs combined with very strong alcohol i.e. uppers - downers. Some believe that it was shady distillers using alternative toxic ingredients to save money. Personally, the shit is minimum 50% alcohol. That alone is enough to make a slightly disturbed person ****ing stupid crazy. From my experiences, it does have something "extra" which a lot of people cant handle.
Just to make this reply even longer, Ill add a short story. My friend was over one night and we were drinking some beer and decided to have some of the aforementioned homemade absinth. Now, I should mention this batch was particularly strong in both alcohol (estmd 80%) and wormwood content. After a couple glasses we were sitting in his car listening to music, he started going off on his girlfriend cheating on him blah blah blah... Next thing I know mother****er says "I gotta go" he jumps out of the car and just starts running! The next day I found him at his house, he had ran all the way home, probably 15 miles through cornfields and shit just to see what his girlfriend was doing.