Gordon Exall has highlighted a recent UK decision in which a psychiatrist (retained to comment on an asserted gambling disorder) began treatment of the claimant while the litigation remained current.
In The Ritz Hotel Casino Ltd v Al Geabury  EWHC 2294 (QB) at  the court commented adversely on the doctor’s failure to disclose that development:
I was particularly concerned by Dr Taylor’s failure to disclose (until after two hours of cross-examination when it was too late) a fundamental conflict of interest, contrary to the last line of his expert’s declaration. The conflict was that he was not simply reporting as an expert, but in the last month he had attended on the Defendant as a treating doctor on four occasions. It was no answer that this did not affect his written evidence because he had no conflict at the time of his report, since the duty is a continuing one, and it did affect him at the joint experts’ meeting and in preparation of the joint report (which also contained the declaration) and when giving oral evidence (in which he referred to the declaration). I was surprised too by Dr Taylor’s suggestion that it did not matter because there was no material in the subsequent consultations which affected his view. This is simply no answer to what is a substantial conflict between a role as a treating doctor and an independent expert. The information communicated to him by the Defendant as his client could not be tested, and could not with any certainty be separated in his own mind.