The finding of mental illness (Social Services Law § 384-b [c]; [6] [a]) is supported by the requisite clear and convincing evidence, namely, the psychologist's uncontroverted testimony (Social Services Law § 384-b [c]). There is no indication that the court coached petitioner to amend the petition to assert mental illness, or was otherwise biased against respondent. Concerning the amendment, the record shows only that petitioner's attorney asked if all counsel could approach the bench, and that following an off-the-record conference, the court stated that the petition would be amended to add a claim of mental ."illness. The amendment was properly allowed in the absence of prejudice and upon conditions that averted surprise. The court, in accordance with respondent's attorney's request, appointed a guardian ad litem for respondent, who had the right to attend respondent's mental health evaluation, and also granted respondent's attorney's request to retain an expert to assist in respondent's defense. Had the motion been denied, petitioner could simply have filed a new petition alleging mental illness. We have considered and rejected respondent's other arguments.