I've taken 20 mg of citalopram for the past 3 years. could it contribute to it being hard to stay awake past midnight? i'm 22 & healthy weight & diet.

Past midnight?: Unless you're a night shift worker, your body's wanting to go to sleep by midnight is not abnormal. On nights you want to stay up later, you might take a little nap earlier in the evening -- but be aware that having a consistent sleep and wake cycle is important in keeping depression at bay. I hope you're feeling well otherwise.