[anythingnonidin]

Yes, exactly. Psychedelics have been described as "nonspecific amplifiers".

A hypothesis I have is that therapists, and their patients, already know many of the things that'll help make them happier - but the patient isn't doing them, because they lack the motivation, or they lack the belief that they're capable of making and sticking with those changes, so why bother trying.

Doing a psychedelic trip in that therapeutic context seems to make the patient motivated to make the changes that they already logically knew would be helpful, and the trip in this context makes them believe they're capable of making and sticking with those changes - so, then they end up making those changes.