Ramayanam is an Ithihas - which means it happened. Puranas means mythology. Many politicans blindly talk about Ramayanam without thought - pl dont ape them. Plus dont you thing other countries right till thailand believe in Ramayanam - which itself should prove thats its more than a myth.
Secondly what Rama drank was Somabhanam (excuse the spelling) which was more of a mind stimulating drink and not local toddy/bhang as we are to belive. No one knows the contents of the drink to talk about it.
Hey even if he was drunk - i wouldn't blame him - who wouldn't after loosing an kingdom, being banished to the forest and top of that loosing his wife.