Its pretty sure bet you'll be forking out for the medication from your own pocket.
Having untreated schizophrenia patients would be very noticeable (1% of the population suffers from it) so I doubt even Poland would allow it. Untreated they can be dangerous.
There are psychiatrists and psychy nurses who speak English but he can't rely on finding one in the right place at the right time.
Every contact I've had with medical, dental and pharmacy's staff has been in English. All the nurses in my wife's course have to speak English to pass their degree, for instance.
Pharmacists always seem to speak English, its seems to be a requirement in all countries.