>> that's a small number of persons who are found excused because their mental illness is so severe it causes them either not to know what they're doing or not to know the wrongfulness of what they're doing. >> people often ask me, well, listen. why didn't she kill herself instead of drowning herself? the kids would still be alive. the problem is she becomes more and more ill with each pregnancy. the sicker you become, the less alternatives are available to you. >> while awaiting trial, andrea yates was placed in the jail's medical facility and treated for psychosis. >> from the time of the tragedy to the time of the trial, she improved. i mean, to the point where she wasn't having hallucinations. >> on september 22nd, 2001, just three months and two days after the murders, yates was deemed competent to stand trial.