Screaming is normal development for a 17th month old Toddler. My son William is almost at that age but at that stage. http://www.whattoexpect.com/toddler/17-month-old.aspx#

Toddlers don't have all the words to express what is in their heads they want to say so easiest way is to scream or have a tantrum.

I find often help is to do a whisper game with the other children. The more the older kids get annoyed and comments - more screaming and frustration the toddler has (my older son (6 years old) get pretty annoyed with his brother, but we try to break into a song or SHHHhhh Shhh rythme a song together to calm William down.
Plus William love love love attention and very active - his personality - differ from my older son - more independent and analytical.

Also separation Anxiety is very normal for a toddlers because they realize how easily they can be separated from the person that makes them feel safest. Redirecting their attention and think of ways to less the pain - might have to simply distract the child attention while mom or dad sneak out if it cause more anxiety(Toddler memories are short)

Good Luck. Hope this helps!