ABSTRACT Suicide is a top ten cause of mortality in the United States, and suicide rates have increased dramatically in recent decades. A recent meta-analysis showed that the suicide rate following discharge from a psychiatric facility was 2,078 per 100,000 person-years (versus 14.0 for the general population). Approximately one- quarter of all suicide deaths occur within 3 months of discharge from a psychiatric facility, making this a period of extremely high risk. With the advent of managed care in the 1990s and the concomitant decrease in hospital lengths of stay, Intensive Outpatient Programs/Partial Hospitalization Programs (IOP/PHPs) were instituted to manage high-risk patients outside of a locked hospital unit. Today, IOP/PHP services are frequently used in some areas as the principal discharge plan for patients upon leaving the hospital. However, there is virtually no evidence examining their clinical effects on suicide risk in this period. While these IOP/PHP services are readily available in some areas of the country, they are virtually non-existent in other regions. If IOP/PHP services have a significant protective effect against suicide following hospital discharge, implementation initiatives to broaden the availability of these services nationwide could be undertaken as a way to bend the curve against suicide. We hypothesize that the intense social and psychological support of IOP/PHPs will be reflected in a reduction in suicide risk among patients who receive treatment through these programs. We will test this hypothesis by conducting a propensity score matched observational study of patients who receive treatment at IOP/PHP services following discharge compared to patients who receive non-intensive outpatient follow-up. Cohorts for these groups will be sufficiently large (over 100,000 per group) to detect even small differences in suicide rates between intervention groups (minimum detectable rate ratio ranging from 0.82 to 0.95, see Table 4). The data for this project will be drawn from Medicaid databases and will be linked with the National Death Index, the most authoritative data source for mortality in the United States. Additionally, we will conduct a national survey of clinical directors of IOP/PHP services to identify and characterize clinical care processes. Survey results will be integrated with claims-based analyses to better understand what care processes may be effective in reducing suicide risk following hospital discharge as well as to understand the variations in quality of care throughout the country among IOP/PHP services. Results from this project would have important implications for policy and discharge planning patterns in the post-hospitalization period. Future directions would include dissemination and implementation initiatives to align discharge planning patterns with clinical evidence. A stakeholder council will be formed during the project to help implement strategies to enhance the availability of the...