Jen, thank you for the info on the amitriptyline. So what happened to the very playful, some what aggressive cat when you gave him/her the meds? You said new behavior was established. Did the medicated cat then become less aggressive?
The medicated cat felt less like chasing the shy cat which gave the shy cat a chance to learn to that the medicated cat did not really mean her any harm when he chased her. (I hope that made sense)