I had one who would scream if I left the room. I tried talking as I walked away saying i'll be right back etc etc, but nothing worked. I decided to ignore the behaviour as I was only ever gone for a few minutes (to pee or grab a drink or throw a diaper outside) and slowing it got better. When he didnt get the attention of me trying to convince him not to scream, he got bored. Gave lots of praise when i came back if they was no screaming