I think Lottie may be onto at least 80% of the problem, Scarlett. The fashion for wood floors instead of carpets, and powerful sound systems with TVs has all added to noise levels going up. I bet you find they have minimalist decor, hard floors etc if you were to look. If the flat is your own property, it will be worth looking to deaden the sound on your side of the ceiling and if you have a google for sound-proffing solutions you'll find some useful info. It'll basically involve installing a shallow false ceiling stuffed with sound-deadening (and fire-resistant) materials. Even if rented, you could badger the landlord about this.
Other useful ploys I have used in noisy conditions include: using earplugs, either wax ones (hard to find now) or those industrial ones that look like mini bean bags; playing a talk radio station whisper - quiet next to my head - distracts my attention from exterior noise; running a rotary fan - makes 'white noise' that masks (as I found) even Spanish teenagers partying in narrow stone streets late at night; plugging in ipod with a long storybook on it, very quietly, again distraction technique.