I have experienced mentally abuse in a different martial art than aikido - not unlike what is described in 'Angry white pyjamas' which I am currently reading, but with a 'brain-washing' twist to it.
My advise is to be sure allways to take time of to listen to one self, and decide if what you are doing is right for you. When one is inside the 'system' it can be very hard to break out. It's not as easy as Reza describes it above, if your are young and gullible. If I had been better at listening to myself when I was in my early 20's, many people would have been spared much trouble and pain.