N.Y. FCT Law § 344.3

§ 344.3. Rules of evidence; psychiatric testimony in certain cases.\nWhen, in connection with a defense of mental disease or defect, a\npsychiatrist or licensed psychologist who has examined the respondent\ntestifies at the fact-finding hearing concerning the respondent's mental\ncondition at the time of the conduct charged to constitute a crime, he\nmust be permitted to make a statement as to the nature of the\nexamination, the diagnosis of the mental condition of the respondent and\nhis opinion as to the extent, if any, to which the capacity of the\nrespondent to know or appreciate the nature and consequences of such\nconduct, or its wrongfulness, was impaired as a result of mental disease\nor defect at that time. The psychiatrist must be permitted to make any\nexplanation reasonably serving to clarify his diagnosis and opinion, and\nmay be cross-examined as to any matter bearing on his competency or\ncredibility or the validity of his diagnosis or opinion.\n