So much of the trauma on M*A*S*H comes from lack of autonomy. Hawkeye expresses this in the finale when he complains about being placed in the mental hospital against his wishes, but even before that he (and everyone else who did not choose to enlist) loses so much free will the second he gets drafted. The army has complete control over everything he does. They decide where he is, when he is allowed to go somewhere else, what he eats, and when he sleeps (and oftentimes he is forced to stay awake for long periods of time; there are so many episodes of this show where Hawkeye is extremely sleep deprived and just has to keep going despite not being able to). Being sent to a mental hospital was just the final flame in this trauma soup that had been simmering for eleven seasons.
