I suspect there is a big difference in Russia between top science universities and everywhere else. In my opinion, humanities education is of very poor quality in Russia so I could well imagine a party culture there. But the curriculum in top science programmes tends to be so intense and passing requirements strict enough that I doubt there is too much partying going on. However, a lot of the coursework I suspect is also still too outdated and often irrelevant.

There is also likely a big difference between students living at home and living in dorms. Who knows what happens in dorms, but the commuting students in my opinion don't tend to get too wild.

Finally, the social scene is just structured very differently. There are fewer elected subjects, and most of the social life happens during/between classes - the whole year just spends a lot of time with each other naturally and bonds over common struggles. There is a culture of trying to involve everyone in some sort of social life. You don't have to sign up for anything - it happens by default. Although I think international students would be treated differently and actually perhaps excluded. Instead of clubbing or going to bars, social drinking revolves more around drinking in someone's kitchen and engaging in pseudo-philosophical conversations.

Of course, my account is from a long time ago so things may be very different now.