my 8 year olds son behavioral problems

my 8 year son was diagnosed with adhd at about the age of 5 he has been on many different types of meds for adhd and to help him sleep.We have noticed that he like to pick on smaller kids very aggresively as well as animals.When he does this he doesnt seem to have any remourse for his actions other than knowing he is in trouble.He also thinks its funny when other are hurt and talks about killing and hurting other people.We have had to place him in the hospital twice for out of control behavior at times it seems as if he holds our family hostage cause we are afraid to go places or visit friends out of fear he might hurt their children we have been to numerous doctors and therapist and councslers nothing has worked is it possible for an 8 year old to be a sociapath.He is getting more and more aggresive (aggressive) yesterday he slapped his mother in the face twice while he was in time out has also left marks and has choked his little sister we no longer know what to do all the doctors want to do is pop more pills in him we are currently trying to change his diet in hopes that helps but i worry about my girlfriend and daughter safety when i go to work any insight would be appreciated

[margypops]

Sounds to me like side effects from the meds he is on , check it out  with your doctor ask about the dosage and if you need to change them. He could be jealous of his sister , something is going on and I would google for info about side effects from the meds .