Why might it be that sometimes when someone is abused for an extended period, they form an attachment to the abusers?

Stockholm Syndrome: Research that syndrome. It can answer a lot of your questions. It's fairly easy to describe what happens but just exactly why has several possible answers. Certainly chronic abuse is more likely to cause the attachment. I believe that in most cases it is a way for those abused to try to win over the abuser for their own safety and survival or safety and survival of those they love in the situation.

Tics course and comp: In the majority , chronic, with partial remission of sx in early adult years..May minority may experience full remission; however, tics generally reappear , perhaps afternoon monhs or years.