I don't think that this song is about any addiction is specific but it is about addiction/sin in general. Hence that he says "They might have different names, but they’re all the same,". I believe that the song is about sin not being 'safe' in him. He says "But the secret’s safe inside, alone and dark it hides, And I’d ignore it, but it won’t go away" Which I believe means that he has sin that he keeps inside but does not confront. When he says "I won’t be the safest place to hide," he is saying that with God's help he can resist sin.
I don't think that this song is about any addiction is specific but it is about addiction/sin in general. Hence that he says "They might have different names, but they’re all the same,". I believe that the song is about sin not being 'safe' in him. He says "But the secret’s safe inside, alone and dark it hides, And I’d ignore it, but it won’t go away" Which I believe means that he has sin that he keeps inside but does not confront. When he says "I won’t be the safest place to hide," he is saying that with God's help he can resist sin.