Best going insane screams

[feinting goats]

Not just your normal i'm going to die screams.  Only screams where they go insane.

Texas Chainsaw Massacre part 2 - girl goes chainsaw crazy

In the Mouth of Madness - Sam Neill's mind finally caves in

Evil Dead 2 - Ash goes over the top

From Beyond - The best IMO @ 16:00

Dracula Dead and Loving it - honorable mention

[Darth Geek]

One of my favorites is the girl Lex's scream in Jurassic Park when she sees the T-Rex.

[MontyServo]

My favorite:

Spoiler

[feinting goats]

One of my favorites is the girl Lex's scream in Jurassic Park when she sees the T-Rex.

awesome.  but alas, she doesnt go insane.  its an i'm going to die scream.

[Darth Geek]

I've always been very fond of Dr. Insano and his laugh/screams.

https://www.youtube.com/watch?v=4fhGS0tAcQg

[Gandalf Lundgren]

Not going insane but the most famous:

[chrisfrost23]

Mostly I experienced scream when I watch a horror film

[RVR II]

Did Feinting Goats make an insane scream before leaving 

[Sideswipe]

If feinting Goats makes an insane scream when no one is around, does it make a sound?

[Rainbow Dash]