I met women who had harmed or killed their kids when I was in prison and since through voluntary work. Most of them claimed PPD or PPP. Some of them would only be there for a short time before being moved to a psychiatric facility. Some were sentenced for some form of neglect despite there being suspicion of intentional malice.
One woman came to prison after being in a hospital because her ex husband had changed his mind over years about her culpability and fought for it to happen. Initially, it was pretty much thought she would be released once the psychiatric staff thought her to be "well" enough..
Not all people who have seriously harmed or killed their children are in prison for that assault/injury. Some aren't even in prison for that at all. They might be in there for drugs that were found in the house after their child was injured for example.
The thing that I found is that in many cases, you'll never really know whether mental illness was the defining factor in their actions. As you can imagine, someone who would intentionally harm their children is likely to be highly manipulative and many of the women I speak of were like that. Even if they initially came across as pleasant and well to do in various ways.
You also of course see people who are obviously plagued by mental illness or cognitive impairment of some kind and incorrectly sentenced to be in prison when they should be in a hospital or therapeutic facility of some kind.
Some of these women were able to make rational plans based on what were delusions. So they might think that the government is trying to take their baby for some form of testing due to the baby being special in some way, so they flee with the baby through the night using "off grid" methods to escape to the wilderness where they won't be found. Cash they withdrew and banked over days. Lying to family about plans to divert them etc.
My experiences have made me think that we need to treat perinatal mental illness more seriously. We need to only apply these terms or have specific terms for people who have a perinatal mental illness that puts themselves or others at risk. And I think that generally, those with a serious mental illness need to have compulsory contact with a multidisciplinary mental health team in the perinatal period and perhaps while they remain the carers of children or other vulnerable people.
A woman like Lynsey Clancy should not be discharged into the community on multiple medications (whether she is taking them or not), reporting symptoms of serious mental illness and it is accepted by staff and her loved ones that she will return to be the primary carer to children. Some sort of safeguarding meeting should take place where it is clear she should not have unsupervised access to the child(ren), even if she can live in the same home as them. This is something they issue to parents all the time while they assess their capability to be alone with their child.
I think we need to get rid of this idea that you can be on strong psychiatric medication and taking that makes you the same as someone who doesn't need that medication to have the same sense of stability and well-being. You're still a person with a severe mental illness which is only controlled by regular adherence to medication and possibly other forms of treatment and therapy. That may have some impact on your independence and ability to care for others in various ways.
I know people with SMIs can lead perfectly independent lives and manage their condition extremely well. But a bit like certain conditions means that you have more "check ins" as a driver, I think the same should occur when someone has a SMI and will be caring for others. The idea that someone can have bipolar, get pregnant and refuse care from the perinatal mental health team doesn't sit right with me.