Let's back up for a second and talk about Philip Seymour Hoffman. Russell Brand wrote this after Hoffman was killed by his heroin addiction:
The reason I am so non-judgmental of Hoffman or Bieber and so condemnatory of the pop cultural tinsel that adorns the reporting around them is that I am a drug addict in recovery, so like any drug addict I know exactly how Hoffman felt when he "went back out". In spite of his life seeming superficially great, in spite of all the praise and accolades, in spite of all the loving friends and family, there is a predominant voice in the mind of an addict that supersedes [sic] all reason and that voice wants you dead. This voice is the unrelenting echo of an unfulfillable void.
Addiction's a bitch to pin down because yes, it's a physical illness, but addicts use for psychological reasons too. It's an anesthetic, a way of hiding from whatever part of their lives or themselves they find intolerable. Taken to its logical conclusion, it's suicide by shelter.
Booze and drugs are a comfort, a respite. One that to a certain sort of person with a certain sort of brain suggests it could be more than that, maybe even a solution to their problems. Then it fucks everything up, which amplifies the need for further retreat, which means you use more, and round and round the garden like a teddy bear.
Suzie and Jon each find and retreat into The Quiet on their own. Then they find each other, and now they have someone to share it with. The love affair with their hiding place is renewed and grows stronger, even seems healthy. They go every chance they get. Then comes the day they figure they can use it to solve their problems. You see?