It's not that other forms of psychotherapy are scientifically shown to be 0% effective; it's just that evidence-based psychotherapy is a surprisingly recent field. Psychotherapy can still work even if some fields of it have not had rigorous studies showing their effectiveness... but you might as well go with a therapist that has training in a field of psychotherapy that has some scientific method behind it.

http://www.mentalhelp.net/poc/view_doc.php?type=doc&id=13023&cn=5