Even for nonforensic clinicians, the assessment of the patient's competence has grown in importance, particularly regarding the issues of informed consent and right to treatment. However, the incompetence of patients with paranoid states, depression, mania, and anorexia nervosa may be so subtle that both assessors and the court are deceived, incompetence is not recognized, and treatment is stalemated. The authors provide guidelines designed to equip the clinician to assess--and to present in an effective manner in court--the clinical findings relevant to incompetence, to the benefit of both the patient's rights and treatment.