Rachel, May I suggest your father seek an alternative opinion of the medications he is currently taking. It may well be he is overdosed and might do better with a protein redistribution diet which would enable a drug such as Sinemet to work better. Parkinsons can cause a patient to be between a rock and a hard place when choosing between mobility and cognition. Dementia is not an unknown side effect of Parkinsons and/or the medicine used to treat the symptoms. Dr. Jonathan Pincus Head of Neurology at Georgetown University Hospital, Washington DC has suggested that patients sometimes improve on a diet low in protein during the mobility hours (usually daytime) with protein taken at night. Ensure or a protein rich milkshake such as used in Instant Breakfast with Ice Cream can be used to provide protein if a patient loses too much weight on the special diet. Check first with your physician and ask for a professional opinion for suitability for your father from your neurologist. The doctor can contact Dr. Pincus to discuss your father's situation.. My mother improved using this method, in combination by deleting several other parkinsons medications and just using sinemet every 2 hours. Each person's chemistry and lifestyle is different. Always check with your physician first. This is a somewhat controversial area. Best to consult your physician first for his/her professional medical opinon. Overmedication can cause problems with halucinating with doctors sometimes using Clozeril which requires blood tests or other antipsychotic medications. Ask your Doctor treating your father to obtain from Dr. Pincus' a copy of the protein redistribution diet if it of interest and medically and appropriate for your father's lifestyle. Dr. Pincus sometimes places patients in the hospital to test for protein sensitivity and medication adjustment. Eric [log in to unmask]