Suicide is a significant and growing public health concern. In 2021, suicide was the 9th leading cause of death for people ages 10–64 in the United States, with rates increasing by 36% between 2000 and 2021 (Centers for Disease Control and Prevention, 2023). People with severe mental illness (SMI), including those with bipolar disorder (BD) and schizophrenia-spectrum disorders (SSD), are at particularly high risk for suicide (Novick et al., 2010; Palmer et al., 2005; Saha et al., 2007). The lifetime suicide attempt prevalence in individuals with schizophrenia, bipolar I or bipolar II disorder, are 27%, 36%, and 32%, respectively (Novick et al., 2010). These rates are far higher than the 2.7% lifetime suicide attempt prevalence in the general population (Nock et al., 2008). Despite the increased risk of suicide among people with SMI, they are often excluded from suicide research because of concerns about potential challenges with their ability to understand and follow study procedures due to cognitive deficits and management of their psychosis severity and risk (Villa et al., 2020). The exclusion of people with SMI from suicide research limits our understanding of the risk for suicidal behaviors over time and the efficacy of suicide prevention treatments among people with these diagnoses.

Emergency departments (EDs) are a common point of contact for people at high risk for suicide. From 2010 to 2020, EDs in the United States treated over 500,000 people each year for deliberate self-harm (National Center for Injury Prevention and Control, 2023). In addition, approximately 10% of people who visit EDs each year have experienced suicidality in the two weeks prior to visiting the ED (Claassen and Larkin, 2005; Ilgen et al., 2009). Furthermore, research has found that over 40% of mental health patients who died by suicide had visited the ED in the year prior to their death (Ahmedani et al., 2019; Da Cruz et al., 2011). Research has also shown that individuals with symptoms associated with SMI, such as psychosis, are more likely to have repeated ED visits over a six-month period (Sirotich et al., 2016). A review of studies on suicidality and the ED identified that psychotic disorders were among the top co-occurring psychiatric diagnoses for individuals presenting to the ED for suicidal ideation (Ceniti et al., 2020). Therefore, the ED is a particularly important context in which to conduct suicide risk assessment and intervention (Betz et al., 2016), especially for those with SMI.

Goldman-Mellor et al. (2019) examined the one-year incidence of suicide and other mortality among ED patients in California presenting with nonfatal deliberate self-harm, suicidal ideation, and any other presenting concern. They found that a clinical diagnosis of psychosis or BD was associated with increased suicide risk among those presenting with deliberate self-harm. The present research aims to further explore the role of psychiatric diagnosis in suicide risk following an ED visit by expanding the outcome to suicide attempts (not solely death by suicide), along with investigating the efficacy of a suicide-focused intervention among people with SMI.

A number of interventions have been developed to specifically target suicidality, including Dialectical Behavioral Therapy (Linehan et al., 2006), safety planning (Stanley and Brown, 2012), and Coping Long Term with Active Suicide Program (CLASP; Miller et al., 2016, Miller et al., 2022). Multifaceted interventions have been found to be particularly effective in reducing suicidal behaviors (Krysinska et al., 2015; Hofstra et al., 2020; Doupnik et al., 2020) and adjunctive interventions offer increased accessibility and generalizability to “real world” clinical settings, as they are less time and resource intensive. CLASP is a multifaceted, adjunctive intervention designed to target suicidality through a combination of case management, individual psychotherapy, and optional significant other (SO) involvement (Miller et al., 2022). CLASP has been adapted for ED populations, consisting of seven brief telephone calls to the patient and up to four calls to an SO identified by the patient. Calls focus on reducing suicide risk through identifying risk factors, clarifying values and goals, planning for the future, identifying a safety plan, encouraging treatment engagement and adherence, and facilitating patient and SO communication and informal problem solving (Boudreaux et al., 2013; Miller et al., 2017). The parent study of the current research, a multicenter study of adults with recent suicidality visiting the ED, compared rates of suicide attempts over the course of the 52-week study between three sequential phases: 1) treatment as usual, 2) universal screening, and 3) universal and secondary suicide screening, resources and a safety plan provided in the ED, and CLASP. They found that, compared with Phases 1 and 2 of the study, patients in Phase 3 of the study showed a 20% relative risk reduction in suicide attempt risk over one-year follow-up (Miller et al., 2017). Furthermore, CLASP has been found to be cost-effective to provide (Dunlap et al., 2019). However, the effects of CLASP have not been examined among people with SMI. Because people with SMI have unique needs that may impact their ability to engage in CLASP, such as greater social isolation (Bornheimer et al., 2020) and cognitive impairment (Reichenberg et al., 2008), it is essential to specifically investigate their response to the intervention.

The present research examined suicide risk among adults with SMI (BD or SSD) identified in the ED compared to those with other psychiatric diagnoses (OPD) over the course of a year, along with the effectiveness of the CLASP intervention among those with SSD and BD. We hypothesized that: 1) participants with BD and SSD will have a higher rate of lifetime suicide attempts at baseline compared with participants with OPD; 2) Among participants in Phases 1 and 2 (non-intervention phases), those with BD and SSD will have a shorter time to and higher rate of suicide outcomes over follow-up compared with participants with OPD; 3) Among participants in Phase 3 (CLASP intervention), participants with BD and SSD will have shorter time to and higher rate of suicide outcomes over follow-up compared with participants with OPD; and 4) those with BD and SSD who received CLASP will have longer time to and lower rate of suicide outcomes over follow-up compared with those not receiving CLASP.