... limberness in doing yard work, long bike rides, and in general. Thought I was just getting old, and that may be the case. But by chance I took a small amount of Benadryl and it had a wonderful effect of my general mobility and especially my exercise performance. Subsequent online searching brought the issue of Parkinsonism and muscle rigidity into my sphere of thought. Perhaps this (quetiapine related side effects) is what has caused my physical deterioration and not just old age. My question is this: is it likely, and to what degree is it likely that after 8 years at 800mg quetiapine that I could be experiencing symptoms of Parkinsonism, more specifically the general stiffness and rigidity which can be associated with taking a medication of this type/quantity over this length of time? Any experience and knowledge would be appreciated. I realize that it could be difficult to answer this question without knowing more, but I'm kind of just trying to get an idea of the likelihood, if at all determinable, of whether or not this(Parkinsonism related rigidity) is something I can/could/might expect to some degree after 8 years of taking this medication at the dose mentioned