Paulene, I agree with China that it is INVALIDE.
I wonder if she had some physical impairment which made walking etc difficult, which might explain her being able to work in a clerical sort of capacity, but have difficulty washing, getting dressed etc.
I have now done some further research on the family I mention, and have discovered that their first child died in infancy, their second was the "lunatic", their third boy died at the age of 4, then they had two more boys, a second daughter who was the "imbecile" and then a final son.
As if this wasn't enough tragedy, the eldest boy died at 22, followed closely by the mother aged 50, then the father died three years later aged 54, leaving the "imbecile" daughter to be put into Darenth Asylum - she was there, aged 13, in 1901 - and the youngest boy to go and live with an aunt. I think the girl died, aged 34, in an asylum.
Fortunately, the three surviving boys seem to have done well, the youngest emigrating to USA at the age of 17, and then followed by his next brother.
Although I am not very closely connected, I may send away for the death certificates to see if this gives any clues to the precise ailments the children suffered, and why the parents died at such a young age.
I am horrified to think that an ailment which could be in some way treated, or at least mitigated by technology these days, might have led to a life in an asylum - although of course, that could be the result of a youthful mistake leading to unmarried pregnancy in some cases.
At the risk of repeating a sentiment often seen on these pages, it is very humbling to see the difficulties our ancestors laboured under, and I am immensely grateful to have the benefits we enjoy now.