My experience seeing my Dad on carbidopa levodopa is that it made him a zombie. I spent 3 months taking care of him exclusively and was with him every day. He has Parkinson's and Dementia. I could see the effects and the change within 30 minutes of taking it. When he wasn't on the med or it was waning he could talk and be confused happy guy. When he's on the carbidopa levodopa his eyes are dark and glassy and he's a zombie. I talked with a PT who works with seniors and he says he immediately knows who's on carbidopa levodopa because of the look in their eyes. It's in the Meth Amphetamine family so it makes sense that this drug is making our old parents look and talk like addicts living under the local freeway bridge. It didn't help his movement or tremors but the Docs insists he be on it. I lost the battle to get him off it. They're still ramming it down his throat even though he's in a wheelchair all the time.