Earlier quoted context omitted.
I recall something that supports this hypothesis. there is good evidence that merely _reading_ the book "feeling good" by David burns (father of CBT) is as effective as medication. this indicates the relationship matters, because we're talking about people who didn't _act_ on the book, but merely _read_ it.
A link for that would be appreciated.
Here's one relevant quote: "The effectiveness of stand-alone bibliotherapy was evaluated in five published studies by a team of investigators headed by Dr. Forrest Scogin from the University of Alabama. These researchers evaluated the effectiveness of Dr. David Burns' "Feeling Good" as well as Dr. Peter Lewinsohn's "Control Your Depression," as self-administered treatments for depression. The investigators concluded that Feeling Good was as effective as a full course of individual psychotherapy or as treatment with the best antidepressant drugs."