Things get a little more muddy if you take the view that there really is no mind-body division, and that human behavior is the result of chemical and neurologic

Things get a little more muddy if you take the view that there really is no mind-body division, and that human behavior is the result of chemical and neurological processes in the brain, which in turn is just another part of the body. It's easy to draw a distinction when physical withdrawal leads to death, but how do you differentiate between physical and psychological pain and suffering when abstaining is not fatal?