Classifying a disease to make a cure

It is amazing how FDA and the pharmaceutical companies operate to so call "Protect Us". Reading Kevin Trudeau's book stating about the FDA and BIG Pharma working for each other instead of working for the American people or shall I say "consumers". In the beginning of his book he talked about something I had any knowledge of.
I didn't know in order for the FDA to so call improve a drug it had to be a disease. When I think about disease I think of cancer, disorders, etc.etc.. Trudeau's book stated, " Once upon a time, you used to get heartburn, not it's called Acid Reflux Disease. Once upon a time people used to be shy, now it's classified as Social Anxiety Disease, which is a disease. Kids who are eating too much sugar or are a little rambunctious are now classified as having Attention Deficit Disorder, which is a disease. If a woman has a low sexual desire, it is now classified as a disease. An alcoholic is no longer an alcoholic, but now has the disease of Alcoholism. "
Why is it that in order to make money you have to classify something as a disease to make a profit for a prescription drug?