The word ‘psychology’ and the phrase ‘scientific credibility’ should appear in the same sentence, unless it is linked in the negative.
I think the comprise an official oxymoron at this point.
I think this discussion needs to make a distinction between research psychology and clinical psychology (counseling). The research end can certainly establish replicable phenomena that defy common sense -- I'm thinking of Harlow's "wire monkey" experiments here, or the studies in which decent people can be induced to inflict pain on others through thought manipulation. These are valuable insights into how ultimately to resolve traumas in individuals, or deliver relief to traumatized groups, such as after Columbine, Aurora or Fort Hood shootings.
It's the one-on-one stuff in the small room with no witnesses that is a particularly ripe area for abuse, and that needs much more rigorous scrutiny.