That's a great question. It's a very difficult one to answer, and there's not a whole lot of research yet that really informs that.
What we do know and understand about the brain is that while understanding may be reduced or diminished, and while there are components of the brain, like inhibitory control and self-regulation, that may be operating at a much lower level developmentally than we would like for an adult, a lot of these individuals do understand right and wrong. Sometimes the NCR, the not criminally responsible, system actually provides a level of treatment intensity that is not an appropriate fit.
We are faced with a system where you may be putting somebody with an FASD who understands right and wrong but can't inhibit or control his or her behaviour with somebody who has experienced a schizophrenic episode where they absolutely had no idea of what reality was or was not.