Unwanted wives were not the only people getting committed to the insane asylums of long ago.
The asylums were also a dumping ground for unwanted old people, as we see in the following article from 1911:
Asylums Crowded with Sane People
TOPEKA, Ks. — H.C. Bowman, chairman of the state board of control, is authority for the statement that the insane asylums are crowded with aged persons perfectly sane, who are sent there by their relatives merely to get rid of them.
Association with the insane often causes them to lose their minds after they have been in the institution for some time.
The same is true in many other states, says Bowman.
Source: The Seattle star. (Seattle, Wash.), 07 Sept. 1911.