Squish head
1. One who has transformed his/her brain from a complex sensory-processing organ critical to life existence, to a mass of ill-functioning goo (squish) with excessive & unmoderated drug-use.
The term "squish head" appeared in the original Twin Peaks, S2 - E5; it was used to refer to the cocaine-running Renault brothers - who were from Canada - as "...glue-sniffing, squish heads...".