Wonderful question, especially since postmodernism has infiltrated the counseling theoretical orientations via multicultural counseling. However, what makes this question even more interesting is that, despite of this success in the field, it seems as though multicultural counseling is still considered "a" practice and not a part of the entire treatment. This means that, regardless of how much a counselor is willing to look at the unique personality traits of a client from a multicultural perspective (ethnicity, sexual orientation, cultural background, religious preference, etc), other aspects of the counseling process remain rigidly attached to its own constructs. This may or may not interfere with multicultural counseling in the end.
One of the closest approaches to Postmodernism is social constructionism: the counselor relinquishes the role of guide and explores along with the client the rationale behind the perspectives that lead the clients to see things the way that they do. Rather than deflect the client toward a "mainstream", the counselor explores where the client's rationale can lead.
Narrative Therapy- as the client tells his story, the counselor re-tells it as what it is: a life story; the story of someone's life experiences. This adds weight and value to what the client is saying, rather than disenfranchising the client, demeaning the primary complaint, and trying to enforce an intervention that leads toward a predictable outcome.
Solution-Based therapy- this therapy is quite radical from traditional counseling in that it rejects the canon of psychotherapy that deals with understanding and digging up the past. Instead, the client's present and future are looked after; the past does not necessarily hold the key to solve your problems.
Notice the key traits of these approaches:
- the client is center-stage
- the therapist is a facilitator and not a leader
- the client's unique traits are taken into consideration
- the client's unique life story is considered essential, whether it completely detours from what is considered "normal" under modernist standards.
All this being said, what would not work on a Postmodern approach is the traditional cognitive model proposed primarily by Freud, and then expanded by other theorists such as Erickson, Maslow, Rogers, et al.
It is true that, regardless of how powerful Postmodern theory is, the basics of human development should be considered as baseline data. Yet, theory is still not "law" and a counselor could legally and professionally elect to bypass the original tenets of psychology and sociology and opt for an alternate intervention that considers the symptom first, and the cause later...or else, that considers no cause at all, but a solution.