Research is a wonderful thing. Looking into late nineteenth century madness (as you do) I came across the autobiography of Anna Agnew, a mother of three who spent 7 years in a lunatic asylum in the 1870s/1880s.

In From Under A Cloud, Anna describes her lifelong suicidal tendencies and the sweeping bouts of depression and delusion that culminated in an attempt to murder her sons in order, in her mind, to spare them the possibilities of suffering insanity as she did. It’s an incredibly readable little book and a great source.