In psychotherapy, various theoretical systems compete for followers. These systems are sometimes referred to as paradigms, orientations, or perspectives, but they are still systems. I think of them as disciplines or fields.The word “paradigm” comes from the Greek word paradeigma, which is a pattern or a model. Thomas Kuhn used it in science to refer to the organising set of practices that define a scientific discipline. Discipline itself in this context would mean a branch of knowledge.An orientation is the determination providing the relative position of something; it can also indicate the direction of a person's interest or attitude. Whenever I go into the building where my practice is located, I get “turned around” and thus a bit disoriented, because I can never tell in which direction Front Street, and thus the harbour, is. What I have to do is think my way out the door to the elevator, then picture the lobby five floors down and the entryway below Flanagan's Restaurant and Irish Pub. Then I get a sense of my relative position in space and I become more oriented.One can also speak of a sexual orientation then one means how one feels inside, whether one feels like a male or a female. This is not sexual attraction (for which gender one has an interest); this is sexual identification. If someone were to say, “All the girls over here and all the boys over there,” any given person might have male genitalia but feel for all the world that she belongs with the girls. That is sexual orientation; it provides one with a sense of where he or she fits in the gendered world.A perspective has to do with the vantage point from which a person views something. High on a hill one has a broad and far-reaching line of sight in many directions, but down in the narrow valley, one can see only so far. However, perspective can also be a figurative way of referring to a person's attitude or point of view about something. A narrow perspective, then, would be limited in understanding and/or tolerance.A field is a sphere of influence, activity, and interest or a branch of study. I am a psychologist, but I am also a Christian. I am interested in the field of psychotherapy, and I approach it with a Christian world view (or perspective). If I were a theologian, I would find keen interest in theology but I could approach it with a natural perspective and an agnostic world view (which might seem oxymoronic to some, but I have met pastors who do not believe in God).So, if you take all these various concepts and mix them together, you have a pattern of interest forming a branch of study that orients one's approach and influences one's activities. These are systems of psychotherapy, patterns of thought that direct how a psychotherapist will conduct his or her practice and what he or she will do while meeting with a client.There are several major systems of psychotherapy. Some examples are psychoanalytic, cognitive, behavioural, systemic, humanistic, and experiential. New forms of psychotherapy, with names reflecting their hybrid natures, keep popping up with as much frequency as there are narcissistic theorists who believe they have discovered or created the final answer, THE approach that will best get the job done.Actually, research shows that all forms of psychotherapy enjoy about the same relative success. Even though the various systems have different ways of conceptualising psychopathology, and thus ways of responding to dysfunction, emotional pain, and cognitive dissonance, they seem to employ some common factors that have been shown to be salient in terms of healing and growth.Recently, at a conference in Cambridge, Massachusetts, USA, I conversed with colleagues from the psychoanalytic perspective on psychotherapy, and we found much in common with one another. That is because the various systems of psychotherapy are converging. Cognitive therapy is becoming mindful, which is another word for being aware of current experience, but awareness of current experience is something that has been central to gestalt therapy for decades. Psychoanalytic psychotherapy has become relational, meaning that the analyst has moved out from behind the couch and meets face to face with the client, interacting in a more dialogical fashion, and accounting for a co-created therapeutic process. In the decade of the 70s gestalt therapy embraced contact, and thus relationship, regarding it to be as important to therapy as nurturing subjective awareness of one's current experience (or phenomenal flow). Thus, when gestalt therapy refers to contact and psychoanalysis refers to intersubjective relationship, they are often talking about the same thing, for relationship in gestalt therapy is considered to be contact over time. Behaviourism has discovered that the field, the overall complex adaptive system in which one finds oneself, has a great deal to do with the outcomes in behavioural modelling. Psychoanalysis has also embraced the field, and such an orientation is called relational systems psychoanalysis. That is close to behavioural systems science. Existential-phenomenological psychotherapy shares many of the same theoretical commitments as gestalt therapy.This converging of the fields of psychotherapy provides challenges to the evidence-based movement in mental healthcare. If, for instance, motivational interviewing, a technique some regard to be a form of psychotherapy in its own right, can be shown to be practiced by people under a different name, within a given theoretical system, then the research “evidence” accrued for motivational interviewing alone should apply equally to motivational interviewing and this form of it by another name. As Shakespeare noted, a rose by any other name would smell as sweet. Evidence for a practice that is conducted by any other name should be as acceptable. And that will become the challenge in the decades ahead, as it becomes increasingly clear that the various systems of psychotherapy are converging and that their ways of doing things what therapists actually do have more in common with one another across the various systems of psychotherapy.What then of the competition for followers? I imagine it will always be that any given beginning therapist will choose a system that just feels right and makes sense to him; however, in the end, therapists will conceptualise differently but practice in much the same way.