"As the therapist, aren't you too involved to provide an unbiased testimony?"
Many expert witnesses are hired by attorneys specifically to render an opinion about a criminal case, a litigant, or a child custody issue, having had no previous professional contact with the involved party. However, there are also many mental health practitioners who are subpoenaed to testify in court about a person who has been in psychotherapy with them. Attorneys at times refer to the former as an expert witness and the latter as the treating doctor although in court these distinctions are blurred because the treating doctor, by virtue of having relevant specialized knowledge that is unknown to the average juror, qualifies as an expert.
The expert witness/consultant has the advantage of appearing to be an objective, independent evaluator. Furthermore, the expert witness is usually supplied with a comprehensive set of documents, including past medical and psychiatric records, job evaluations, arrest records, and the like, much of which is not in the possession of the treating doctor because persistent initiatives to obtain such documents do not usually occur in the clinical setting.
The treating doctor, in contrast, has the advantage of knowing the individual in depth, having multiple therapy contacts over an extended period of time, as compared to the usual single-visit assessment by the expert witness/consultant. In terms of liabilities, the expert witness can be depicted as biased and favoring the side who has employed him or her (as the so-called "hired gun"), whereas the treating doctor could be perceived as the biased advocate of the patient.
Although most clinicians would not voluntarily seek out the experience of being scrutinized in the courtroom, when their patients are involved in legal