I have observed literally hundreds of different individuals. I can say without a doubt that every single one of them has shown neurotic, abnormal, repetitive behaviours. The scientific term for those is “stereotypy”. Stereotypies can range from self-harming behaviours with the animal banging their head against the wall until they literally rip the skin off, to chewing on concrete where they will wear their teeth down to the gums and fracture teeth. It can be regurgitating their food continually. That can have all sorts of implications with acid burning of the esophagus.
There are all sorts of other abnormal behaviours like elevated hyper-aggressive behaviour. It all accumulates into what we have termed chronic stress. The implication of chronic stress is exactly the same as it is for us. It's just not good for your health.