Narcolepsy is a condition that causes sudden, uncontrollable sleep. The singer is being made to do things for other people, which makes him delirious all of the time, staying up and working to do things that he is not interested in:
"I read dead Russian authors volumes at a time" - What he reads for school.
"I write everything down except what's on my mind" - No time for his own thoughts.
"'Cause my greatest fear is that sucking sound" - The shame or losing from not doing what he's supposed to do.
"And then I know that I'll never get back out" - All that keeps him going is drinking. He's left alone and drowning.