One rule originated with Freud. In a 1912 paper, he advised doctors practicing psychoanalysis that the physician “should be opaque to his patients, and, like a mirror, show them nothing but what is shown to him.”
In psychoanalysis, there is a specific rationale for this rule. The theory holds that patients tend to re-enact with therapists the relationships they had with their parents. This is called transference. By paying careful attention to this unfolding drama — as it plays out, right there in the office — the therapist and patient can uncover and resolve childhood conflicts. If a therapist interjects information about herself, she clouds the mirror and compromises the process.
But I’m not a psychoanalyst. I agree there are good reasons for a therapist to adopt a posture of neutrality. For one thing, patients need to be free to take the discussion anywhere, including uncomfortable or taboo territories. If therapy were reciprocal, therapists might close off avenues of conversation that they themselves might want to avoid.
During the years of practice, I developed my own rules in therapy. Gradually, that helped me in attracting patients with the corresponding resonance. The personality of the therapist is, in many cases, much more important than the Paradigm.