Child mental health, homelessness, and the shelter system: evidence from Medicaid in New York City.

We identified children who resided in the New York City shelter system during 2015-2020 by matching address histories in Medicaid insurance claims to publicly available homeless shelter addresses, permitting examination of health care use before, during, and after shelter stays. We found that 4.5% of NYC children aged 4-17 with consistent Medicaid coverage entered shelter over a 3-to-5-year period. After shelter entry, children had increased probabilities of receiving mental health services, including therapy and diagnoses of neurodevelopmental disorders but little change in physical health service use. Children placed in shelters colocated with mental health services were similar to children entering other shelters prior to entry but had particularly large and sustained increases in use of mental health services afterwards. Children without prior mental health claims placed in shelters colocated with mental health services were 38%-48% more likely to receive mental health therapy and 14%-16% more likely to receive neurodevelopmental diagnoses than similar children placed elsewhere. These children were also more likely to receive Supplemental Security Income and stayed in shelter longer. This example illustrates the potential of linking administrative data sets in order to study vulnerable populations. This article is part of a Special Collection on Methods in Social Epidemiology.