Table 1.

Definitions

Experience with homelessness is lacking a fixed, regular, and adequate night-time residence, including being unhoused or living in supervised shelters, supported housing, or places not intended for human habitation. Housing insecurity is being at risk for losing housing and lacking resources to obtain other permanent housing or receiving housing support services. However, because the terms “homeless” and “housing insecurity” are defined in multiple ways across the literature, we accepted any definition reported in the literature

Serious mental illness (SMI) is the presence of schizophrenia, other psychotic disorders, or bipolar disorder, consistent with the VA National Psychosis Registry (NPR). We acknowledge that there are multiple ways that SMI is defined. For example, some broader definitions of SMI include major depressive disorder (MDD) and posttraumatic stress disorder (PTSD). For the purposes of this evidence mapping review, we tracked which studies used the narrower (i.e., NPR) definition and which used a broader definition, or which self-identified their targeted patient population as having SMI but did not provide enough information to determine whether it was the broader or narrower category

Primary care is a service that “provides long-term, patient-provider relationships, coordinates care across a spectrum of health services, educates, and offers disease prevention programs” to the general population.53

Primary care engagement is the range of structured interactions between an individual patient and a primary care provider and/or primary care clinical team that has a direct linkage to a prescribing primary care provider (e.g., MD, DO, NP, PA). Specific engagement interactions can occur across a spectrum from initial contact (including patient identification and referral to primary care), establishment of a therapeutic relationship with a primary care clinic, and longitudinal patient-centered care delivery. In this context, a key component of engagement is the establishment of a relationship with a primary care clinic with the intent for regular, proactive contact for the purpose of managing health over time