Who is Gloria Knudson from Valis and what is their importance?

A gentle, civilized friend of Horselover Fat's, Gloria asks him for Nembutal pills to add to the stock that she needs to kill herself. She has a habit of taking LSD and in the six months since they have seen one another, it is clear to Fat that she has lost her mind. Her mother commits her to Mount Zion Hospital in San Francisco, CA, after a suicide attempt, but Gloria is discharged, claiming that she is cured. Fat jumps to the conclusion that this is a call for help, invites Gloria to stay with him, and fails to provide the pills. He realizes that she is dead inside. She does not respond to his proposal that she temporarily move in with him, but after staying overnight, without the sexual entanglement that Fat wants, she vanishes.