I physically abused a mentally and physically handicapped man 5 years ago, while working as a careworker.

I am trying to find information on therapy that will help me to explore why I did this, in order to prevent it occurring again. I have found resources on anger and stress, have been in communication with my employer from this event, and am currently seeking counselling. I would like to know if there are resources specifically for therapy for abusers, or case studies of abuse of physically or mentally handicapped people in institutional settings.

thank you