Psychotropic drugs and psychotherapy?

In some advice books, I've found blanket advice that patients being treated with lithium should also receive concomitant psychotherapy. Lithium, like other mood-stabilizing medications, is a long-term medication. What justification/indication should such a patient receive psychotherapy? To put it bluntly: I'm taking medication XYZ, but now I also need psychotherapy. What psychotherapist would agree to…