Reasonable but not functional?

How does one convince a depressed person that “everything is all right” when her life really does suck? How does one convince an obsessive-compulsive patient to stop religiously washing his hands when the truth of what gets left behind after “normal” washing should be enough to make any sane person cringe? These problems put therapists in the curious position of teaching patients to develop irrational patterns of thinking—patterns that help them view the world as a rosier place than it really is. Counterintuitive as it sounds, it’s justified because what defines a mental disorder is not unreasonable or illogical thought, but abnormal behaviour that causes significant distress and impairs normal functioning in society. Treatment is about restoring a person to that level of normal functioning and satisfaction, even if it means building cognitions that aren’t precisely “rational” or “realistic.”