Are you underweight normally or has this just happened? Did your dr prescribe a new antidepressant which can make you lose weight? I really don't think they can put you in the hospital because of that unless they thought you needed medical care immedietly. I will tell you I take Seroquel 100mg. and I have gained 40 lbs. My weight was normal before now I am heavy. I don't like it at all. Is there another reason you are underweight?