Problem:
Suicide is a widespread public health problem and nearly one million people die by suicide worldwide every year (World Health Organization, 2021). In 2020, suicide was among the top 9 causes of death for people aged 10-64 in the United States (US; Centers for Disease Control and Prevention, 2021). In the same period, 1.2 million Americans attempted suicide and 12.2 million had thoughts of suicide (Substance Abuse and Mental Health Services Administration, 2021). Military Veterans are a population at particular risk of suicidal behaviors (Moradi et al., 2021), with suicide rates rising faster compared to the general US population (Bryan et al., 2015; Ramchand, 2022). Given the widespread and seemingly unrelenting nature of suicide, particularly among military personnel and Veterans, researchers and clinicians have called for increased study into risk factors of suicide and suicide-related phenomena (Schafer et al., 2022a, Schafer et al., 2022b), including suicidal ideation, attempts, and death, a category broadly referred to as suicidality.
Traumatic brain injuries (TBIs), defined as alterations in brain function following trauma to the head (Centers for Disease Control and Prevention, 2015), have been identified as a risk factor for suicidality among Veterans (Barnes et al., 2012), Service Members (Schafer et al., 2022a, Schafer et al., 2022b), adolescents (Richard et al., 2015), older adults (Thompson et al., 2006), and treatment-seeking outpatients (Brenner et al., 2011). Since the early 2000s, tackling TBI within military personnel has been identified as a policy priority given heightened prevalence and risk from explosions, military training, or other combat-related factors (CDC, 2013; Centers for Disease Control and Prevention, 2015). Beyond increasing risk for suicidality, TBIs among Veterans also increase risk of anxiety, depression, and PTSD. This heightened risk of psychiatric conditions in the context of TBI is particularly problematic in that TBI, by way of psychiatric conditions, has been found to confer risk for physical health problems (Hoge et al., 2008).
Socio-environmental factors are frequently cited as risk, or protective, factors for suicidality (Turecki et al., 2019). More specifically, research has identified a host of social integration deficits (e.g., lack of social connection and deficits in social skills) that contribute to suicidality (Calati et al., 2019; Tsai et al., 2014; Tsai et al., 2015). Indeed, social integration difficulties have held as a risk factor nearly doubling the risk of suicidality in adolescents (Speckens and Hawton, 2005), older adults (Szanto et al., 2012), young adults (Kleiman et al., 2012), and adult outpatients (Silva et al., 2015). US military personnel, often from nontraditional family structures associated with lower levels of social integration (Griffith and Bryan, 2016), may be at heighted risk, calling for more research into the role of social integration and its link suicide in this population.
Outside of the field of psychology, sociology contains somewhat extensive investigation into the link between social integration and suicidality. A review paper (Stack, 2021) outlined that divorce and marital separation are significant stressors which elevate the risk of suicide (Denney et al., 2015; Ide et al., 2010; Stack and Scourfield, 2015). Likewise, the authors point to research demonstrating that children are protective against suicide death among women (Agerbo, 2005; Mäki and Martikainen, 2009; Qin et al., 2003). A previous, more foundational, sociological paper (Stack, 2000) studied 84 papers and found robust support for the link between social integration and reduced experience of suicidality. The most pronounced support of social integration as a buffer from suicidality has been among the study of marital integration, wherein more than three quarters of the research found a significant relationship. Indeed, marital dissolution has long been considered a risk factor for suicide (Stack, 1980) and social integration may be the mediating factor. That is, married people as compared to non-married people experience significantly less loneliness and this is consistent with social integration being integral to a relationship with suicidality (Stack, 1998).
While the literature has largely assumed that TBIs and social integration deficits independently and uniquely contribute to suicidality, that is likely not the case. Indeed, TBIs have been shown to increase the risk of social integration difficulties. This has been evident in children (Andrews et al., 1998; Janusz et al., 2002; Rosema et al., 2012), adult outpatients (Dahlberg et al., 2006; Knox and Douglas, 2009; Struchen et al., 2011), and older adults (Ritchie et al., 2014; Kumar et al., 2020). TBIs may also hinder re-integration into civilian life after military service, an important factor for long-term outcomes among Veterans (Hays, 2016). Indeed, in an overview of the TBI and suicidality literature, Wasserman et al. (2008) called for additional research into the link between TBI, social integration, and suicidality.
Additional study into the roles of TBI and social integration towards suicidality can give us insight into the veracity of theories of suicide, particularly in the somewhat understudied group of TBI patients (Trivedi and Humphreys, 2015). Indeed, theories have been proposed to understand the causes of suicide, and many of the most commonly-studied theories (Schafer et al., 2022c) propose some aspect of deficits in social integration as a cause of suicidality. For example, the Interpersonal Theory of Suicide (Van Orden et al., 2010), Integrated Motivational-Volitional Theory (O'Connor and Kirtley, 2018), and 3-Step Theory of Suicide (Klonsky and May, 2015) propose that thwarted belonginess, social problem-solving deficits, and lack of connectedness, respectively, cause some aspect of suicidality. Importantly, research has generally supported these three theories across many samples, including: Service Members, Veterans, community members, outpatients, inpatients, adolescents, and geriatric populations (Schafer et al., 2022c). Moreover, it has been recommended to further explore the role of thwarted belonginess in predicting suicidality among military populations (Short et al., 2019).
Studying these three phenomena simultaneously could improve understanding of potential contributors to suicidality and provide fodder for novel treatment development. If social integration is found to be a mediating factor between TBI and suicidality, social integration could be an important treatment target for patients experiencing TBI, social integration deficits, and suicidality. This is particularly exciting given that treatment effects associated with even gold-standard treatments for suicidality are modest. Indeed, even after a full course of treatment of Cognitive-Behavioral Therapy or Dialectical Behavior Therapy (Hawton et al., 2016) or psychopharmacological interventions (Cipriani et al., 2005) many patients still report suicidal ideation. Positive treatment outcomes (e.g., PTSD) for military compared to civilian populations may be smaller still (Straud et al., 2019), with recommendations for robust studies to investigate treatments that target mediators, including socio-environmental factors, in military populations with TBI (McIntire et al., 2021).
Thus, in the present project we investigated the simultaneous experience of history of TBI, social integration, and suicidality. We employed a sample from a population with historically elevated rates of TBI and suicidality, military Veterans (Gardner and Yaffe, 2015; Kang et al., 2015). The elevated rates of two crucial phenomena decreased the likelihood of floor effects and allowed us to explore the relevant variables with relatively high frequency. Based on previous literature, we hypothesized that (1) TBIs would be positively and significantly associated with suicidality, (2) TBIs would be negatively and significantly associated with social integration, and that (3) social integration would be negatively and significantly associated with suicidality. As no previous literature could be used to support a hypothesis regarding the mediating role of social integration in the relationship between TBI and suicidality, we conducted exploratory analyses to determine if social integration acts as a mediator in this fashion. Need Assignment Help?
Explain it.