Drinking shouldn't really have an extremely adverse affect on your studies unless you let it. Most people tend to concentrate on the physiological effects of drinking like the hangovers, liver damage or reduced memory capacity. These are all true, but in the end it depends on the person. I've seen way too many people get stuck on the idea of getting wasted and partying it up all the time and usually these same people tend to neglect school for a "siq fr1day nit3 at da club br4hhh!11". In my opinion its more about how you treat alcohol, if you leave it as an occasional thing (once a fortnight, special celebrations etc - its really up to you) then you should be fine, but if you get stuck on the idea of "partying it up" then its more than likely you wont get the scores you are aiming for.
Or you may just be a extremely gifted individual and still be able to balance a heavy social life with heavy studying, this is entirely possible (see: Melbourne High School, Presbyterian Ladies College)