Someone who doesn't like psychotherapy could easily refer to this book for its satirical exposé of therapy, but the book is not designed to say therapy is a hoax: It is merely an exaggeration of a potential issue in couple's therapy, in the case that one person trusts the therapist while the other does not. The book doesn't have anything to say about healthy therapy, but it has a lot to say about the dangers of certain approaches to couple's issues.
For instance, there is an implicit danger that is nicely illustrated by Eleanor's dubious decision to indulge in frequent and erotic massages, done by men who claim the point is not to bring Eleanor to orgasm; it's just "Die Handhabung Therapeutik"—but it's literally sexual behavior. Contrast that treatment to Will's treatment. They make Will watch as one of his friends is electrocuted during "therapy," which is enough to make him paranoid and horrified, but he is powerless to leave.
So, perhaps something should be said for disenfranchisement, or the loss of power in one's own treatment. There is a reversal of enfranchisement in this story: At the beginning, the wife is disenfranchised, with no outlet for her deep emotions from years of difficult struggle; at the end, she is completely pampered and spoiled, and her husband is humiliated and disenfranchised. The novel is pointing to enfranchisement as a sign of health, as if to say healthy couples are those who genuinely desire to enfranchise their partner in the relationship.