Assessing the Contribution of the Deinstitutionalization of the Mentally Ill to Growth in the U.S. Incarceration Rate

We assess the degree to which the mentally ill who would have been in mental hospitals in years past have been transinstitutionalized to prisons and jails. We also assess the contribution of deinstitutionalization to growth in the U.S. prison population. We find no evidence of transinstitutionalization for any demographic groups for the period 1950–80. However, for the 20-year period 1980–2000, we find significant transinstitutionalization rates for all men and women, with a relatively large transinstitutionalization rate for men in comparison to women and the largest transinstitutionalization rate observed for white men. Our estimates suggest that 4–7 percent of incarceration growth between 1980 and 2000 is attributable to deinstitutionalization. While this is a relatively small contribution to prison growth overall, the results suggest that a sizable portion of the mentally ill behind bars would not have been incarcerated in years past.