What Is The Treatment For The Diagnosed OCD And Panic Disorder Without Agoraphobia?

Hello, my 18 year old granddaughter has been diagnosed with OCD and Panic disorder without agoraphobia.It started about 5 months ago with small symptoms such as hand washing several times and always using hand sanitizers. Now, it has expanded to real issues like not drinking water because the bottle doesn't look right or thinking someone may have put something in it. She has to look at all the packinging that foods and liquids come in. If they are not sealed properly or have some dirt on the package, she can not get it. If unopened food in the fridge was not placed there by her, they have to be thrown away and then replaced by her. Food items cannot be placed in the trunk of a car. And , the list goes on. Biggest concern is that because of the food issues, she is losing too much weight and I am concerned about what to do about the expreme weight loss. She cannot eat at restaurants or fast food because she doesn't know if the food has been touched or something put in it that could harm her!