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or M.M.S. A severe mental syndrome characterized by excessive grinding of the teeth and chewing of the jaw. Named after the famous actress Mary McDonnell who developed this rare and unheard of syndrome during the shooting of the film "Donnie Darko" (her chewing is seen in the family dinner scene) Patients are usually extremely angry and unstoppable when having MMS. There is no cure for MMS and comes and goes in various frantic episodes. Patients must usually be strapped down to prevent assault on others.
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