In a number of cases, courts have found that counsel's failure amounted to unconstitutionally ineffective assistance. In Bouchillon v. Collins, 907 F.2d 589 (5th Cir. 1990), a habeas corpus case, Bouchillon sought to set aside a guilty plea on grounds that he was mentally incompetent at the time of the plea, and that his attorney's failure to investigate his competency prior to the plea constituted ineffective assistance. The record before the court of appeals showed that Bouchillon "in all probability" suffered from post-traumatic stress disorder both at the time of the alleged offense and at the time of his plea. At the evidentiary hearing, trial counsel admitted his knowledge of Bouchillon's past mental disorders, that Bouchillon had been institutionalized, and that he was on medication. Defense counsel performed no investigation into Bouchillon's mental health history because Bouchillon appeared to him to be rational, and because he did not feel an insanity defense would be successful. The Fifth Circuit held that "(i)n this case, counsel's lack of investigation after he had notice of Bouchillon's past institutionalization, fell below reasonable professional standards," and permitting Bouchillon to plead notwithstanding his incompetency sufficiently undermined confidence in the outcome to satisfy the prejudice element of ineffective assistance. Bouchillon, 907 F.2d at 595-97.