At the beginning, sure, you'll feel this overwhelming fear that everyone is ahead of you and you will make the lowest grade and somehow people will find out and point and laugh at you. So you'll study like crazy right up until that first gross anatomy test that you'll take on no sleep in some caffeine-induced trance. After that, though, you'll learn what your best study methods are and how best for you to use your time. After that, you'll discover that there is plenty of free time to have a family life, have friends, go to parties. In the clinical years, your free time depends on your rotation.
Surgery tends to lend itself to hospital work and sleep only.
Psychiatry tends to give you more free time than you could possibly fill. The others fall someplace in the middle. Generally the programs that do this tend to be the more competitive ones - surgery, orthopedics, ENT, neurosurgery, etc. Each school's chapter selects a small group of students to join the society, generally in their junior or senior years. Academic activities such as research, performance in clerkships and electives and extracurricular program participation are generally included in the selection criteria.