In an epilogue, Charlie is discovered by his parents in a catatonic state and does not show any movement despite being hit reluctantly by his father. After being admitted to a mental hospital, it emerges that Helen sexually abused him when he was young, and his love for her (and empathy for her troubled youth) caused him to repress his traumatic memories. This psychological damage explains his flashbacks and derealization phases throughout the book. In two months Charlie is released, and Sam and Patrick visit him. In the epilogue, Sam, Patrick and Charlie go through the tunnel again and Charlie stands up and exclaims that he felt infinite.
He comes to terms with his past: "Even if we don't have the power to choose where we come from, we can still choose where we go from there". Charlie decides to "participate" in life, and his letter-writing ends.