They don’t cause Parkinson, they cause parkinsonian type extrapyramidal symptoms. These symptoms can become chronic and continue for years even after you sop taking the drug. I don’t know how fast benzropine kicks because I stopped taking it ten years ago.

The answer is yes, some anti-psychotic meds can indeed cause parkinsonism symptoms. But please do not confuse the mumbling and tremors with full-blown idiopathic Parkinson’s disease.

Benztropine is an anticholinergic. They are not as commonly used to treat Parkinson’s disease except for certain symptom relief as they do have a number of side effects. However they are often used to control tremors and drooling.

Anticloringerics work by blocking the acetylcholine in order to compensate for the lowered dopamine and serotonin levels found in Parkinson’s disease. The idea is to restore a balance to the levels of firing of these neurotransmitters.

Here is a link to benztropine, also known as Cogentin
http://www.drugs.com/mtm/benztropine.html
http://www.drugs.com/pro/benztropine.html

If you are taking an anti-psychotic med which caused the parkinsonism symptoms, it might be a good idea to explore your alternatives there as you do not want to be taking benztropine forever.

Did you doctor put you on a graduated dosage? That is steadily increasing the dose to the intended dosage? It may take several days to see any effects if it is indeed going to be effective for you.
http://nervous-system.emedtv.com/benztropine/benztropine-dosage.html

Do be aware of the side effects of the benztropine as it can blurred vision and dizziness which makes driving problematic.

Best Wishes