Is it normal to have tiny pupils

I have a friend who drinks a lot. Sometimes I wonder if he does more because his pupils are always tiny. I know hes own prescription meds now but he wasnt before so im wondering if he is prone to "self medicating". He acts kind of odd sometimes, drives terribly bad and looks likes hes been drinking when he hasnt he even said so himself once that he looked drunk but he wsnt. Im just wondering if tiny pupils means youre on something and if so what? I have no experience on pills or anything like it but I know in my city its very common unfortunately and not hard to find if you want to and he has lots of connections. I heard that tiny pupils means youre on a pill so it made me suspicious because evertyime I see him I react to his pupils because never seen it on anyone else I know.