Behdasht means "HEALTH". There are two different words in Persian for "health" : Behdasht and Salamat. The first one roots in pure Persian language and the other one has come from Arabic literature into Persian language. Both words are by and large used equally in Iran. BEH means healthy and DASHT means preserving. So BEH+DASHT equals "keeping the health at its optimal level". There is another word , TANDOROSTI whose meaning is very close to that of the previous ones ; TAN means body and DOROSTI refers to HEALTHY STATE. So, totally it means nothing but "healthy body or keeping body in health"
DANESHKADEYE BEHDASHT equals school of (public ) health
All kinds of illicit drugs especially opiums are called MAVAD by addicts and general population. MAVAD means material but implicitely refers to illicit drugs by people.This word has been in common use for at least half a century in Iran and continues to be the single most common word for illicit drugs in Persian language.