Taken from the story “The Bell Jar” by Sylvia Plath
Shock therapy ( shock treatment)- noun
Definition : treatment of chronic mental conditions by electroconvulsive therapy or by inducing physiological shock.
http://en.m.wikipedia.org/wiki/Shock_therapy_(economics)
From page 135: “He thinks you should have some shock treatments at his private hospital in Walton”
This part shows when illness became severe. I know understand the meaning better and how it relates to Esther’s mental state.