What metaphors are used in Fear and Loathing in Las Vegas by Hunter S. Thompson?

In Chapter One, Thompson and his attorney pull to the side of the road to pick up a hitchhiker. In a metaphorical sense, the hitchhiker represents both the reader (who is a newcomer to this drug-twisted world) and whatever fraction of the narrator's consciousness is confused about his distorted mental condition. The hitchhiker symbolizes anyone who might enter this situation innocently. His reaction to Thompson and his attorney provides a yardstick by which to measure how detached from reality they have already become.