Andrea Yates is a good exemplar for guilty but insane. She DID commit the crime- and when she is on medication she can understand the implications of her actions. Without medication she is insane, legally and psychologically. She is always mentally ill- regardless of meds or not. Think of it as diabetes- the individual is always a diabetic, but can be medicated and regulate the blood sugar, or choose to be unregulated. Because she has a history of violent behavior when off her medications (and suidical when on them because of the memory of her actions), and because schizophrenia is extremely difficult to treat, I would advocate for continued hospitalization until there is strong evidence that she is in remission (which, giving current treatment guidelines, is extremley unlikely). She is not fit for a prison population- she would act out, cause more problems and probably become a victim. She should be in a locked mental hospital where she can be protected from herself. Her husband does bear some responsibility- but so does society in that we need to learn to actively treat the mentally ill and not ignore and shun them.
Schizophrenia is highly resistant to treatment and prognosis is very, very poor for those with active cases. I have spent much of my professional career working and doing research on schizophrenia and related diseases and see relatively little progress. If diseases such as cancer had such poor outcomes we would be up in arms and screaming at congress. When someone is diagnosed with cancer, we rush to the family's aide, send flowers and run telethons. When someone is diagnosed with a mental illness we shun and blame the family and the individual, hide, and ignore. Perhaps instead of blaming Andrea Yates we should see her case as a call to action for better treatments, better medication compliance, and greater research. What she did was beyond wrong, and she must pay the consequences. At the same time, she has little capacity to understand or prevent such violent behavior in the future- and thus she must be protected from herself. Perhaps if she had received adequate treatment this tragedy could have been avoided. In the children's memory, if nothing else, we need to fight for better treatment and research for the mentally ill.