28 CFR 541.6: Mentally ill inmates.

If it appears you are mentally ill at any stage of the discipline process, you will be examined by mental health staff.

(a) Competency to Participate in Disciplinary Proceedings. If evidence indicates that you cannot understand the nature of the disciplinary proceedings, or cannot help in your own defense, disciplinary proceedings may be postponed until you are competent to participate. The Unit Disciplinary Committee or Discipline Hearing Officer will make this decision based on evidence, including evidence presented by mental health staff.

(b) Responsibility for Conduct. You will not be disciplined for conduct committed when, as the result of a severe mental disease or defect, you were unable to appreciate the nature and quality, or wrongfulness of the act. The UDC or DHO will make this decision based on evidence, including evidence presented by mental health staff.