Evidence of mental disease or defect of the respondent excluding his responsibility under this article is not admissible at the fact-finding hearing unless the respondent serves upon the presentment agency and files with the court a written notice of intention to rely upon such defense. Such notice must be served and filed before the fact-finding hearing and not more than thirty days after the conclusion of the initial appearance, whichever is sooner. In the interest of justice and for good cause shown, however, the court may permit such service and filing to be made at any later time prior to the conclusion of the fact-finding hearing.
N.Y. Family Court Law § 335.1