Risperidone
"Our Son is 23 and put on 0.25 micrograms of Risperdal twice a day in September 2005, due to not being able to get a prescription for 0.25. we were splitting the 0.5 tablet in half. this was ok as the prescribed medication had a line in the middle. 
Our son did seem to be calmer at first. 
Our son was in a residential home during the week and returned home weekends.
After going to collect him a few  weeks ago, we were so shocked as he seemed all over the place, getting stuck saying one word, jerky movements of upper limbs. it was heart-breaking.
We then noticed the brand of Risperdal had changed and they were a dark red tablet. We then realised this tablet should have never been divided.
The GP  advised us to stop the medication."