My 8 year old diagnosed with ASD has had many vocal tics since he was 5 years old. They have all been very quiet, soft sounds. He is non verbal. In the last week and a half he's had this new tic. He screams at the top of his lungs.... Ahhhh and at the end a blood curdling scream. Every minute of the day until he falls asleep. Needless to say we feel horrible for him and it's very difficult for our family. Anyone else had to deal with this? Any advice? How long did it last?