Douglas Harper's Etymology Dictionary
deinstitutionalization
1967 (disinstitutionalization is attested from 1955), from de- + institutionalization.
Wiktionary
deinstitutionalization
n. 1 the process of abolishing a practice that has been considered a norm 2 the process of releasing a person from a facility where their freedom to leave has been restrained 3 the process of reducing a person's dependence on an institutional environment
Usage examples of "deinstitutionalization".
One consists of the mentally ill, turned out into the streets when deinstitutionalization became the rage in the 1970s.