Possible Clues:

• 1-Across side effect, perhaps
• Feeling of persecution
• “It’s not ____ if they’re really after you” (tagline of the 1998 film Enemy of the State)
• Mental disorder characterised by delusions of persecution
• What 'strikes deep,' in Stephen Stills' 'For What It's Worth'
• What "strikes deep," in Stephen Stills' "For What It's Worth"
• 'Just a heightened sense of awareness,' per John Lennon
• 'There is no literature and art without ___': Thomas Pynchon
• Irrational fear or suspicion
• Quietly a prince admits love, one sort of obsession