Once the event has occurred, the alleged criminal has an interest in presenting a picture that is consistent with his own interests, so mental data is important. For example, most people would ask the defendant how he or she was feeling at the time of the alleged crime. The defendant would probably give a long, drawn-out story about how he was feeling, consistent with whatever position he or she wanted to defend.
Consider this ethical dilemma. Suppose the defense psychiatrist discovers that a patient is malingering (a medical and psychological term that refers to fabricating or exaggerating the symptoms of mental or physical disorders). Should the doctor get off the case, remain as the advocate for the defendant, or go to the prosecution with information on the defendant that could work to the prosecution's advantage?
Can a defense psychiatrist who has conducted an evaluation go over to the prosecution? The way it normally works is that the prosecution might know whether or not the psychiatrist has visited a defendant in jail. If three psychiatrists visited a defendant in jail, and the names of only two are advanced by the defense to support the claim of “not responsible by reason of mental disease or defect,” it is reasonable for the prosecutor to assume that the third psychiatrist found something that is not going to be of use to the defense; otherwise his or her name would be advanced too. The prosecutor then moves to subpoena the third psychiatrist, whose name has not been advanced by the defense. Thus he can be used as the prosecution's witness. The psychiatrist now can agree to aid the prosecution, as it is fair game if the judge allows his testimony to be entered into court as evidence.
Now let’s take the above situation a little further. Suppose a psychiatrist is hired by the court to conduct an evaluation. There are issues of advocacy (the pursuit of influencing outcomes), when the court psychiatrist can also be the treating psychiatrist. For example, while the court psychiatrist is doing an evaluation, he or she may also be doing a scientific probe; information thus gained does not hold the kind of doctor-patient relationship of loyalty towards the patient. The psychiatrist visits the patient and explains that though he may sound like a psychiatrist and look like a psychiatrist, in this capacity he is not the patient’s doctor. What discussions go on between them will not be bound by the oath of confidentially. It will be reported to the court. At this stage a sort of distancing is suppose to take place. Often, however, it turns out that the court psychiatrist may be working as an evaluator, but is also treating the patient. This brings up the issue of whether the doctor should be treating the patient both as an evaluator and as a treating doctor, because of the issue of conflicting loyalties.