Texas Constitution art. 1 §15-a

No person shall be committed as a person of unsound mind except on competent medical or psychiatric testimony. The Legislature may enact all laws necessary to provide for the trial, adjudication of insanity and commitment of persons of unsound mind and to provide for a method of appeal from judgments rendered in such cases. Such laws may provide for a waiver of trial by jury, in cases where the person under inquiry has not been charged with the commission of a criminal offense, by the concurrence of the person under inquiry, or his next of kin, and an attorney ad litem appointed by a judge of either the County or Probate Court of the county where the trial is being held, and shall provide for a method of service of notice of such trial upon the person under inquiry and of his right to demand a trial by jury. (Added Nov. 6, 1956.)