Not sure what "drungs" are - obviously part of unknown's own perculiar vernacular. Hmmm ... rather than speak for a whole country perhaps 'unknown' would do better to realise his / her own parochialism instead of reinforcing it with overly general statements? The meaning of a word depends where you're from and who you are with - "Mullered" can indeed mean intoxication due to drugs within the UK, as it can mean intoxication due to alcohol. If 'unknown' had met anyone outside of his ward he / she would no doubt be aware of that.
I got mullered on an assortment of intoxicating things.