Understanding the Relationship between Posttraumatic Stress Disorder and Suicidality and Its Implications for Treatment
An extensive empirical literature has documented the relationship between posttraumatic stress disorder (PTSD) and suicidality, including suicidal ideation (Nock et al., 2009; Vanderploeg et al., 2015), suicide attempts (Krysinska & Lester, 2010), and death by suicide (Gradus et al., 2010). Review the existing research on PTSD and suicidality, including discussion of co-morbid disorders (e.g., depression) as mediating factors in the relationship. Discuss potential mechanisms for the observed relationships between PTSD and suicidality, addressing neurobiological, biological, and social factors. Lastly, discuss treatment implications, and the utility of PTSD oriented interventions in reducing risk for suicidal behavior.
Understanding the Relationship between Posttraumatic Stress Disorder and Suicidality and Its
Implications for Treatment
Posttraumatic stress disorder (PTSD) was introduced in the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-III; American Psychiatric Association, 1980). Since its addition to the DSM, the criteria for a traumatic event, as well as the criteria of symptoms for diagnosis have changed in almost each additional version of the DSM (e.g., DSM-III (1980) 3rd ed.; DSM-III-R (1987) 3rd ed., revised; DSM-IV-R, (2000) 4th ed., text revised; DSM-5 (2013) 5th ed.). Yet, the spirit of the diagnosis has not changed. In the most recent version of the DSM, there are four categories of symptoms required for diagnosis: intrusion (e.g., recurrent, instructive memories, nightmares), avoidance (e.g., avoiding distressing memories or thoughts of the traumatic event), negative alternations in cognition and mood (e.g., persistent, exaggerated negative beliefs about the worlds, feelings of detachment), and alterations in arousal and reactivity (e.g., reckless behavior, hypervigilence; DSM-5, 2013). While 89.7% of individuals experience a DSM-5 Criterion A traumatic event, far fewer go on to develop PTSD (Kilpatrick et al., 2013). The most recent national survey of mental health disorders estimated that the lifetime prevalence of PTSD in the United States is 6.8% (Kessler et al., 2005).
Similarly, suicide is a pressing health concern in the United States as it is the tenth leading cause of death and the US suicide rate has steadily risen over the past decade (Centers for Disease Control and Prevention [CDC], 2011). In addition, the lifetime prevalence of serious suicidal ideation (9% ; CDC, 2011) and suicide attempts (3%; Borges, Angst, Nock, Ruscio, & Kessler, 2008) is high. To reduce the rate of suicide, many researchers have attempted to identify risk factors that precede and are able to predict future suicidal thoughts and behaviors (Bentley et al., 2016). Identifying risk factors may help to identify individuals that are at heighten risk for suicide and may also provide information on additional treatment targets if the risk factor is amenable to change.
One such diagnosis that has been posited as a potential risk factor for suicide is PTSD. Past literature has demonstrated a strong relationship between PTSD and suicidality. In fact, lifetime incidence of suicidal ideation in patients was PTSD was second only to individuals with depression and lifetime incidence of suicidal attempts in patients with PTSD was third to depression and bipolar disorder. PTSD was also the only anxiety disorder from DSM-III-R that had a significant relationship with both suicide ideation and attempts (Sareen, Houlahan, Cox, & Asmundson, 2005). Meta-analyses have shown a strong positive association between PTSD and suicidality, including suicidal thoughts, behaviors, plans, attempts, and deaths (55 studies on young adults and adults, Hedges g=0.783, p<.001, Panagioti, Gooding, & Tarrier, 2012; 25 studies on adolescents, d=0.701, p<.0001, Panagioti, Gooding, Triantafyllou, & Tarrier, 2015). When specifically evaluating PTSD as a risk factor of suicidality with a meta-analytic approach, Bentley et al. (2016) found that a diagnosis of PTSD was the strongest predictor of suicidal ideation and suicide attempts compared to other anxiety disorder diagnoses, as PTSD was formerly classified as an anxiety disorder prior to DSM-5.
Furthermore, investigators have examined the role of mediators and other mechanisms that may underlie this relationship between PTSD and suicidality. One such variable that has examined is depression. A meta-analysis investigating the role of comorbid depression in this relationship demonstrated that PTSD and depression both significantly contribute to suicidality. In addition, this meta-analysis reported that increased depressive symptoms in individuals with PTSD resulted in higher levels of suicidality (Panagioti et al., 2012). Relatedly, in a study of 28,546 active duty service members worldwide, individuals with both PTSD and depression were 2.6 times more likely to report suicidality in the past year than individuals with either diagnosis alone (Ramsawh et al., 2014).
Given the evidence for a strong relationship between PTSD and suicidality, it is necessary to understand this relationship and the mechanisms that may play a role in the relationship. In addition, it is important to consider the clinical significance of this relationship and how treatment and intervention efforts may benefit for a better understanding of this relationship.
PTSD and Suicidal Behaviors
PTSD and Suicide Ideation
There is a plethora of research demonstrating the relationship between PTSD and suicidal ideation. In a systematic review, Krysinka and Lester (2010) concluded that there was a moderate association with PTSD and suicidal ideation; however, when they calculated a Phi coefficient for nine studies that reported suicidal ideation, there was a relatively weak relationship (ϕ=.008 to .035). Still all nine studies they reviewed reported a positive relationship between individuals with PTSD reporting more suicidal ideation than those without PTSD. Across numerous samples and populations, the association between PTSD and suicide ideation remained significant when controlling for demographic variables, sexual assault history, traumatic life events, alcohol dependence, a lifetime diagnosis of depression (Ullman & Brecklin, 2002); attention-deficit hyperactivity disorder, major depression, and separation anxiety disorder (Clum & Weaver, 1997); sex, self-reported depression (Mazza, 2000); and other psychiatric disorders (Wunderlich, Bronisch, & Wittchen, 1998). One study reviewed found that the association between lifetime suicidal ideation was no longer significantly related to PTSD after controlling for psychiatric variables (Phillips et al., 2005). All of these studies evaluated lifetime or current suicidal ideation, thus no studies reviewed evaluated the effect of PTSD on the development of suicidal ideation (Krysinka & Lester, 2010).
In a meta-analysis evaluating the relationship between anxiety disorders and suicidality, Bentley et al. (2016) found that for diagnosis-specific analyses, PTSD was the strongest predictor of suicide ideation. Another meta-analysis demonstrated that with 13 studies evaluating the relationship between PTSD and suicidal ideation, there was a large and significant effect (Hedges g=1.091, p<.0001; Panagioti et al., 2012). In a systematic review and meta-analysis of suicidal ideation and PTSD in adolescents, Panagioti et al. (2015) found that of 22 studies, 18 reported a significant positive relationship between PTSD and suicidal ideation and four studies reported a non-significant positive relationship. The overall effect size of these 22 studies was strong, positive and significant (d=.714, p<.0001). This review also found that rates of suicidal ideation were comparable in adolescents with PTSD (30-80%) and adults with PTSD (20-70%; Panagioti et al., 2015).
Taken together, there is robust evidence for a strong positive relationship between PTSD and suicidal ideation in both adolescents and adults. In addition, studies have demonstrated that other mental health disorders can play a role in this relationship. For instance, one study reported that major depressive disorder mediated the relationship between PTSD and suicidal ideation (Leitner, Comptom, Houry, & Kaslow, 2008). Another study demonstrated that war veterans with PTSD and comorbid disorders had an increased risk for suicidal ideation, beyond the increased rate of ideation for those with PTSD alone (Jakupcak et al., 2009).
PTSD and Suicide Attempts
In addition to suicidal ideation, there are ample studies examining the relationship between PTSD and suicide attempts. Indeed, Panagioti et al. (2012) included 42 studies in their meta-analytic examination of the relationship between PTSD and suicide attempts, which they found was strong, positive, and significant (Hedges g=0.752, p<.0001). This meta-analysis included studies with samples aged 15 years and older. Another systematic review and meta-analysis focused only on adolescents age 11-21 years old and found that with 18 studies examining the relationship between PTSD diagnosis and suicide attempt in adolescents there was a similarly strong association as found in the prior meta-analysis (d=0.697, p<.0001; Panagioti et al., 2015). Again, Panagioti et al. (2015) found that adolescents with PTSD have similar rates of suicide attempts compared to adults with PTSD (15-50% and 10-40%, respectively). Beyond meta-analyses, other studies have used large nationally representative samples to examine this relationship. The National Comorbidity study found that individuals with PTSD were six times more likely to attempt suicide than matched controls in a nationally representative sample in the US (Kessler, Borges, & Walters, 1999). Another study found that the rate ratio for PTSD and lifetime suicide attempts was 1.9 for a probability sample of adults across six European countries (Bernal et al., 2007).
While most studies compare individuals with PTSD to individuals without PTSD, one study examined individuals who had experienced at least one traumatic event with and without developing PTSD (Wilcox, Storr, & Breslau, 2009). This study used a prospective study design that evaluated students in 19 public schools entering first grade across 15 years. Their sample included 1,272 individuals, of whom 81% reported at least one traumatic event and 6% of the total sample developed PTSD. Overall, the results showed that developing PTSD following a traumatic event had a robust association with a subsequent suicide attempt, even after controlling for sex, race, age, alcohol abuse or dependence, drug abuse or dependence, and previous major depressive episode (relative risk ratio=2.7, p<.01). The researchers also examined the difference between assaultive violence (36% of sample reporting traumatic events) and non-assaultive violence traumas. Neither experiencing assaultive nor non-assaultive traumatic events alone, without PTSD, were associated with increased risk of a subsequent suicide attempt. Using survival analyses with individuals who experienced a traumatic event without developing PTSD as the reference group, they found that PTSD following an event that did not include assaultive violence was not significantly related to a suicide attempt; however, PTSD following an assaultive violent event had a strong association with suicide across models controlling for demographic variables, lifetime alcohol abuse or dependence, drug abuse or dependence, and major depressive episode (RR=3.2, p<.01; Wilcox et al., 2009). This study offers evidence that not only is the development of PTSD related to a subsequent suicide attempt, but the type of trauma experienced may also play a role in the relationship between PTSD and suicide attempts.
Many studies have evaluated the effects of comorbid mental health disorders on the relationship between PTSD and suicide attempts, with mixed results. For instance, one study with a community sample found that the relationship remained significant after controlling for comorbid depression (Davidson, Hughes, Blazer, & George, 1991). After adjusting for psychiatric and physical disorders, the relationship between current PTSD and last year suicide attempt remained significant in a large Canadian community sample (Sareen et al., 2007). Maloney and colleagues demonstrated that the association between PTSD and lifetime suicide attempt remained significant after controlling for drug dependence, borderline personality disorder, and persistent suicidal thoughts (Maloney, Degenhardt, Darke, Mattick, & Nelson, 2007). In a sample of US Veterans, the relationship between PTSD and suicide attempts remained significant and had a similar effect size when including history of traumatic brain injury in the model (Brenner et al., 2011). Other studies have demonstrated that after controlling for other psychiatric disorders (Wunderlich et al., 1998) and sex and depressive symptoms (Mazza, 2000) the relationship between PTSD and suicide attempts was no longer significant. These three studies, however, examined past suicide attempts and did not evaluate the relationship between PTSD and future suicide attempts.
PTSD and Suicide Deaths
While there are substantially less studies evaluating the relationship between death by suicide and PTSD, the studies that have examined this association show mixed results. Krysinka and Lester (2010) concluded that PTSD is not associated with death by suicide based on five studies with contradictory findings that examined the relationship between suicide following PTSD diagnoses. They noted that death by suicide is a rare event, which makes it difficult to study (Krysinka & Lester, 2010). One study following this review has demonstrated that PTSD may increase the risk for death by suicide (Gradus et al., 2010). This study used a nested case-control study design with the entire population of Denmark, which included 5.4 million people aged 15-90 years. Individuals with a diagnosis of PTSD had 9.8 times higher rate of suicide compared to individuals without PTSD. After controlling for depression, martial status, and income quartiles, the strongest identified confounding variables, individuals with PTSD had 5.3 times higher rate of suicide compared to individuals without PTSD. When testing the relative excess risk due to interaction, which allows the researchers to assess additive interactions using odds ratios, they found that individuals with a diagnosis of both PTSD and depression had a significantly higher rate of suicide than would be expected based on the additive independent effects of the diagnosis alone (Gradus et al., 2010). This study offers promising data into the relationship between PTSD and death by suicide; however, more studies are needed to fully understand the relationship between PTSD and suicide. An updated systematic review in 2012 also concluded that no clear relationship can be discussed between PTSD and death by suicide due to the small sample of studies evaluating death by suicide as an outcome and the conflicting results of studies that have examined this relationship (Panagioti et al., 2012).
Potential Mechanisms Underlying the Relationships between PTSD and Suicidality
Neurobiological and Biological Factors
There are many observed neurobiological changes in PTSD than have been hypothesized to affect the propensity for future suicidal behaviors. One such change occurs in the hypothalamic-pituitary-adrenal (HPA) axis. In individuals with PTSD, there are noted changes to the HPA axis, such as lower 24-hour urinary cortisol levels, as well as changes in the secretion of norepinephrine and dopamine, and changes to how those neurotransmitters are metabolized (Charney, Deutch, Krystal, Southwick, & Davis, 1993). Prolonged, chronic stress causes the HPA axis to be hyperactive. This increased activity causes increased levels of cortisol and adrenocorticotropin in the blood plasma, which stimulates catecholamine synthesis by neurons, causing cell atrophy and neuronal loss. After time, the loss of neurons causes paradoxical changes in the HPA axis function (i.e., lower cortisol secretion, increased corticotrophin-releasing hormone activity; Sher, 2010). Some researchers have stated that both individuals with PTSD and individuals with a history of suicidal behavior have reduced HPA axis activity, and they suggest that this may underlie the relationship between the two (Oquendo et al., 2003; Keilp et al., 2010). Conversely, other researchers have found that suicide and major depressive episodes are associated with HPA axis overactivity, including increased cortisol levels, and reduced responsiveness to glucocorticoid receptors (Tarrier & Gregg, 2004). This is the opposite of the change in the HPA axis found in individuals with PTSD (Yehuda, Giller, & Mason, 1993). Still others have posited both hyper- and hypo-activity of the HPA axis, in addition to dysfunction of the serotonergic system and excessive activity of the noradrenergic system play a role in the suicidal behaviors and are mechanisms underlying the relationship between PTSD and suicide (Van Heeringen, 2003). One study examined the relationship between exposure to childhood trauma and a specific gene related to the HPA axis (FKBP5 haplotype). The authors found that this gene was significantly associated with an increased risk of suicide attempts suggesting that there may also be a genetic factor that predisposes individuals with exposure to trauma to suicide attempts (Roy, Hu, Janal, & Goldman, 2007). Accordingly, research suggests that the HPA axis is involved in both PTSD and suicidal behavior; however, more research is needed to fully understand how changes in the HPA axis relate to the relationship between PTSD and suicidality.
Another neurobiological aspect of PTSD is the alteration in the serotonergic system. When an individual experiences stress, serotonin (5-hydroxytryptamine or 5-HT) is released into the frontal cortex to help decrease anxiety and reduce depressive symptoms (Weiss, 2007). Yet, when an individual experiences severe stress or traumatic reactions, there can be excessive serotonin activation in the brain (Weiss, 2007). When the trauma is chronic or persistent, or if the individual has intrusive memories or reexperiencing symptoms (e.g., flashbacks), there is chronic serotonin activation, which can result in overall serotonin depletion (Matsumoto et al., 2005). This reduced availability of serotonin makes it difficult for the central nervous system to control emotional responses to future stressors. This process has been hypothesized to lead to experiencing hyperarousal symptoms after trauma exposure. Impulsive and aggressive behaviors are also associated with low serotonin function (Mann, 2003; Sher, Oquendo, Galfalvy, Cooper, & Mann, 2004). In addition, lower serotonin levels have been demonstrated in individuals with a history of suicide attempts (Muck-Seler, Jakovljevic, & Pivac, 1996). Similarly, one study demonstrated that suicidal individuals with and without PTSD had a significantly lower concentration of platelet 5-HT compared to non-suicidal individuals and health controls, suggesting that serotonin is related to suicidality (Kovacic, Heinsberg, Pivac, Nedic, & Borovecki, 2008). Other studies have investigated how certain gene polymorphisms related to serotonin relate to traumatic experiences and suicidality. For instance, one study showed that the relationship between life stressors and depressive symptoms, suicidal ideation, and suicide attempts was mediated by a polymorphism in the promoter region of the 5-HT T serotonin transporter (Caspi et al., 2003). Another study found that the relationship between physical and sexual abuse in childhood and suicide attempts in adulthood was moderated by having a specific genotype related to serotonin (5-HTTLPR; Gibb, McGeary, Beevers, & Miller, 2006). Thus, it has been proposed that lower serotonin release and reuptake may play a role in the relationship in PTSD and suicide behaviors, especially suicide attempts. Taken together, these studies suggest that the serotonergic system is involved in the relationship between traumatic experiences, traumatic stress, and suicidality.
The endocannabinoid system has also been proposed as a system that may be related to PTSD and suicidality. This system plays a role in reducing fear and anxiety, reducing the memories of aversive events, and regulating sleep (Sher, 2010). Since sleep abnormalities and fearlessness are related to increased suicidality (Sher, 2010; Van Orden et al., 2010), this system has been proposed to play a role in the development of suicidality in individuals with PTSD (Sher, 2010). More research is needed to understand the role of the endocannabinoid system in PTSD. In addition, prospective studies are needed to understand the role of this system in the development of PTSD and suicidality.
Hyperreactivity of the limbic system may also contribute to the relationship between PTSD and suicide. Both positron emission tomography (PET) scans and functional magnetic resonance imaging (fMRI) have shown that there is hyperreactivity of the amygdala to trauma-related stimuli (Dickie, Brunet, Akerib, & Armony, 2008). In addition, the frontal region failing to regulate reactions of arousal and distress are related to the exaggerated startle response and flashback symptoms of PTSD. These changes in the orbitofrontal cortex and amygdala can impair decision-making and increase impulsivity, both of which may contribute to increased suicidal behaviors (Monkul et al., 2007; Braquehais, Oquendo, Baca-García, & Sher, 2010).
Lastly, it has been hypothesized that some of the genetic, epigenetic, and environmental influences that may predispose an individual to develop PTSD after experiencing a trauma may also increase the vulnerability to suicidal behavior (Sher, 2010). For instance, one study identified maternal PTSD as a risk factor for her children developing PTSD. Specifically, researchers found alterations that resulted in increased glucocorticoid receptor responsiveness in children whose mothers have PTSD (Yehuda, Bell, Bierer, & Schmeidler, 2008). Other studies have found that childhood trauma may be related to epigenetic changes that may relate to suicidal behaviors later in life (Brodsky & Stanley, 2008). Early traumatic experiences have been shown to change methylation of DNA in the hippocampus in rats (Brodsky & Stanley, 2008). In a post mortem study, individuals who died by suicide had increased methylation in hippocampal DNA (McGowan et al., 2009).
Research has also examined the role of social support as a protective factor in the relationship between PTSD and suicidality. Panagioti, Gooding, Taylor, and Tarrier (2014) demonstrated that perceived social support moderated the relationship between the number and severity of PTSD symptoms and suicidal behaviors. For individuals who reported levels of perceived social support at least one standard deviation above the mean, having more PTSD symptoms and greater severity of PTSD symptoms was related to a decrease in the likelihood of suicidal behavior. Similarly, another study found that higher levels of social support were related to lower risk of suicide for individuals with PTSD but were not significantly related for controls (Kotler, Iancu, Efoni, & Amir, 2001).
Conversely, Jakupak et al. (2010) reported that in a sample of Operation Enduring Freedom (OEF)/ Operation Iraqi Freedom (OIF) Veterans satisfaction with social networks was less protective for suicide risk in those with PTSD compared to those without PTSD. For Veterans with PTSD, having high satisfaction in social networks showed a 39% reduction in the likelihood of being classified as having elevated suicide risk, compared to an 80% reduction for Veterans without PTSD (Jakupak et al., 2010). Likewise, for OEF/OIF Veterans with PTSD or depression, there was a significantly smaller protective effect of post-deployment social support on suicidal ideation (Pietrzak, Russo, Ling, & Southwick, 2011). Following up on this study, DeBeer and colleagues found when OEF/OIF Veterans had high levels of post-deployment social support, there was no significant relationship between PTSD-depression symptoms and suicidal ideation. Yet, when these Veterans reported low levels of post-deployment social support, PTSD-depression symptoms had a positive relationship with suicidal ideation (DeBeer, Kimbrel, Meyer, Gulliver, & Morissette, 2014). Together, the literature suggests that for individuals with PTSD, having higher levels of perceived social support may help mitigate the risk of suicidality; however, the magnitude of social support as a protective factor for individuals with PTSD is still unknown.
Facets of the Interpersonal Theory of Suicide
The interpersonal- psychological theory of suicide (IPTS) proposes three distinct constructs that are involved in the development of suicidality: thwarted belongingness, perceived burdensomeness, and acquired capability for suicide (Joiner, 2005; Van Orden et al., 2010). The ITPS states that thwarted belongingness and perceived burdensomeness lead to suicidal desire (e.g., suicidal ideation, planning); however, for an individual to make a lethal suicide attempt, he or she must have acquired capability for suicide, in addition to suicidal desire. Acquired capability for suicide includes having a lowered fear of death and an increased pain tolerance (Van Orden et al., 2010). Researchers have examined how facets of this theory may relate to the relationship between PTSD and suicidality. For instance, Bryan and colleagues found that PTSD symptoms significantly predicted higher levels of thwarted belongingness and higher levels of perceived burdensomeness, but exposure to combat regardless of PTSD diagnosis did not significantly predict either (Bryan, Cukrowicz, West, & Morrow, 2010). These results suggest that thwarted belongingness and perceived burdensomeness may be an underlying mechanism in the relationship between PTSD and suicidal ideation. Other studies have also demonstrated some support that PTSD symptoms are related to thwarted belongingness (e.g., Bryan & Anestis, 2011; Monteith et al., 2013) and perceived burdensomeness (e.g., Monteith et al., 2013). In addition, these studies have offered some support that thwarted belongingness and perceived burdensomeness are associated with suicidal behavior after accounting for PTSD symptoms, suggesting that these constructs play a role in the relationship between PTSD and suicidality. Likewise, Davis and colleagues found that thwarted belongingness and perceived burdensomeness partially mediated the indirect relationship between PTSD symptom clusters and passive suicidal ideation (Davis, Witte, Weathers, & Blevins, 2014).
In regards to acquired capability for suicide, Silva, Ribeiro, & Joiner (2015) demonstrated that a PTSD diagnosis was significant related to increased acquired capability for suicide. Conversely, Bryan and colleagues found that combat exposure, but not PTSD, accounted for a small percentage of the variance of acquired capability for suicide, suggesting that PTSD is not significantly related to increased acquired capability for suicide (Bryan et al., 2010). When evaluating symptom clusters of PTSD, Bryan & Anestis (2011) found a significant relationship between one symptom cluster of PTSD (i.e., reexperiencing symptom cluster) and acquired capability for suicide. Zuromski and colleagues were unable to replicate this finding in a sample of trauma-exposed undergraduates examining PTSD symptom clusters relationship with acquired capability for suicide. They found no significant relationship between reexperiencing symptoms and either facet of acquired capability for suicide (i.e., fearlessness about death, increased pain tolerance); however, they did find a significant negative relationship between the anxious arousal symptom cluster and fearlessness about death and a positive relationship between numbing symptom cluster and pain tolerance (Zuromski, Davis, Witte, Weathers, & Blevins, 2014). To add to the mixed finding, Spitzer and colleagues found that the anhedonia symptom cluster served as a suppressor variable and masked the relationship between the other symptom clusters and acquired capability for suicide. In this study, the anxious arousal cluster was negatively associated with fearlessness about death, the anhedonia cluster was positively associated with fearlessness about death, and the reexperiencing symptom cluster was not associated with either facet of acquired capability for suicide (Spitzer, Zuromski, Davis, Witte, & Weathers, 2017). While there is converging support that thwarted belongingness and perceived burdensomeness play a role in the relationship between PTSD and suicidality, there is mixed results and inconclusive evidence on the role of acquired capability in the relationship.
Research from the past four decades demonstrates that PTSD is a predictor of future suicidal ideation and behavior. In addition, there is evidence to suggest that depressive symptoms amplify the effects of PTSD on suicidal behaviors. Consequently, PTSD and depressive symptoms would seem to be high priority targets for treatment to prevent suicidal behaviors. Yet, the Department of Veterans Affairs and Department of Defense Clinical Practice Guidelines for PTSD, the International Society of Traumatic Stress Studies, the manual for cognitive processing therapy, and suggestions for prolonged exposure therapy state that high suicide risk is a contraindication for PTSD treatment (Department of Veterans Affairs and Department of Defense, 2010; Foa, Keane, Friedman, & Cohen, 2008; Resick, Monson, & Chard, 2007; van Minnen, Harned, Zoellner, & Mills, 2012). Despite the expert consensus recommending against PTSD treatment for those at acute risk of suicide, some researchers have argued that there is not enough research to support these suggestions (Bryan et al., 2016; Bakalar, Carlin, Blevins, & Ghahramanlou-Holloway, 2016). Bryan et al. (2016) argued that the limited knowledge about the potential iatrogenic effects of PTSD treatment on suicidality is due to studies on the efficacy and safety of PTSD treatments tending to exclude patients that endorse suicidality. Similarly, Bakalar et al. (2016) contended that PTSD patients with suicidality are unrepresented in randomized controlled trials (RCTs) for PTSD. In addition, they proposed a need for implementing a standardized method of reporting suicide risk methods. Of 38 RCTs for PTSD, 23 excluded patients for suicide related items and only two studies outlined suicide risk monitoring procedures (Bakalar et al., 2016). In addition to the potential harm for individuals with PTSD at risk for suicide, suicide risk has also been found to be related to poorer response to cognitive behavioral therapies (Tarrier, Sommerfield Pilgrim, & Garagher, 2000).
Since assessing suicide risk in PTSD trials has been noted as a limitation of past literature, recent studies have begun to examine the effects of PTSD treatment on suicide ideation and behavior. One such study evaluated the effects of cognitive processing therapy (CPT) and prolonged exposure (PE) on symptoms of PTSD and reports of suicidal ideation. CPT is a trauma-focused cognitive behavioral therapy that involves two integrated components: cognitive therapy and exposure in the form of writing and reading about the traumatic event (Resick & Schnicke, 1992). PE is another manualized therapy that involves psychoeducation, retraining of breathing, behavioral exposure to environmental reminders of the traumatic event, and imaginal exposure to the memory of the traumatic event. The trial of these two therapies assessed 163 women that were recent victims of sexual assault over five time points (pre-treatment, post-treatment, 3 months, 9 months, and 5-10 years post-treatment). Participants were randomized into CPT, PE, or a waitlist group that was then randomized to CPT or PE six weeks later. Across both treatments, there was a significant decrease in the mean level of suicidal ideation with a sharp decline during the treatment period and smaller decreases during the follow-up period. In addition, more changes in PTSD symptoms were related to more changes in suicidal ideation. The relationship between reduction in PTSD symptoms and suicidal ideation remained significant when controlling for reported hopelessness or comorbid major depression. When controlling for hopelessness, the strength of the relationship decreased, suggesting that hopelessness may account for some of the association between PTSD and suicidal ideation. When comparing CPT and PE, participants in the CPT condition had larger decreases in suicidal ideation over time than those in the PE condition. In both groups, decreases in suicidal ideation were maintained over the five to 10 year follow-up period (Gradus, Suvak, Wisco, Marx, & Resick, 2013). This study offers promising support that treating PTSD symptoms in individuals reporting suicidal ideation may decrease both symptoms of PTSD and suicidal ideation. There are some noted limitations of this study. First, the study used a single item to assess for suicidal ideation (Beck Depression Inventory, item 9). Second, it only included women with a specific type of trauma (i.e., sexual assault). The effects of PTSD treatment on suicidal ideation may differ in men or in survivors of other types of trauma, such as combat and non-interpersonal traumas. Third, this study only evaluated suicidal ideation, which is only one component of suicide risk. Current treatment guidelines do not recommend trauma-focused treatments for individuals who have acute suicide risk, yet these guidelines do not clearly define the level of suicide risk that would render trauma-focused treatment iatrogenic. This study offers evidence that trauma focused treatment may reduce suicidal ideation. Future research should examine the effects of trauma-focused treatment in individuals with a wider range of suicide risk, while implementing safety procedures for those individuals.
Another recent study examined the changes in suicidal ideation and changes in risk for suicide attempts in a randomized clinical trial of the efficacy of group CPT-cognitive component only (CPT-C) and group present-centered therapy (PCT) in 108 active duty US Army personnel (Bryan et al., 2016). Group CPT-C included 12-sessions of group therapy focused on subjective appraisals of stressful life events, specifically concerning the traumatic event. This therapy emphasized cognitive restructuring of maladaptive automatic thoughts. PCT is a psychotherapy that does not explicitly focus on trauma. The group PCT focused on problem solving and symptom management strategies without explicit discussion of trauma-related experiences. There were no significant differences between groups on suicidal ideation at any time point during treatment or follow-up assessment. In both groups, there was a significant decrease in suicidal ideation from pre-treatment to post-treatment (B= -.24, p<0.001), but there was no significant difference between pre-treatment suicidal ideation and suicidal ideation at six-month or 12-month follow-ups. Thus, the percentage of individuals reporting suicidal ideation decreased during the active phase of treatment and then returned to pre-treatment levels during follow-up. Importantly, suicide ideation did not increase during or after treatment. There were no suicide attempts during the study period. The authors also found that changes in suicidal ideation had a small, but significant association with changes in depression severity (B=.01, p<0.001), but did not have a significant association with changes in PTSD symptoms. Consequently, the results of this study suggest that group CPT-C, a trauma-focused treatment, does not exacerbate suicide risk and may decrease suicidal ideation in active duty service members with PTSD. Again, this study had limitations in that it assessed a specific population of trauma survivors (i.e., Army soldiers) and outcomes were only related to suicidal ideation. While this study did assess for other suicidal behaviors, there were no suicide attempts and the authors did not report on other suicidal behaviors (e.g., self-harm, preparatory behaviors). In addition, this study evaluated group therapy format, which may not generalize to individual therapy. Since social support and belongingness relate to the relationship between PTSD and suicidality, the group component of these interventions may prove especially helpful in reducing symptomology. Furthermore, the trauma-focused therapy, CPT-C, did not include the exposure component, which may have unique effects on suicide risk. Despite these limitations, this study did offer support that group CPT-C, a form of trauma-focused therapy, does not increase suicide ideation or risk in individuals with PTSD and suicidal ideation (Bryan et al., 2016).
Given the neurobiological underpinnings of PTSD and suicidality, pharmacological treatments may prove effective in reducing both symptoms of PTSD and risk for suicide. While pharmacotherapy has been shown to be effective in reducing symptoms of PTSD, suicide risk has been an exclusion criteria or has not been addressed in many studies and systematic reviews regarding medication and PTSD (e.g., Marshall, Beebe, Oldham, & Zaninelli, 2001; Stein, Ipser, Seedat, Sager, & Amos, 2006; Hidalgo & Davidson, 2000). Yet, one study did find less suicidality in PTSD patients who were taking medication than those who were not (Tarrier and Gregg, 2004). Conversely, a meta-analysis of studies in the FDA database concluded that there was increased risk in patients with PTSD taking sertraline compared to the suicide risk in the general public. While there were zero deaths by suicide in PTSD clinical trials of sertraline, the incidence of suicide attempts in the trials was 0.13% and the patient exposure years (PEY) suicide incidence of suicide attempts was 0.67%. This meta-analysis did not make comparisons of suicide risk for individuals with PTSD taking sertraline and those in a control group (Khan, Leventhal, Khan, & Brown, 2002). More research needs to be done to determine the effects of pharmacological treatments for PTSD on suicidality.
In both psychotherapy and pharmacological trials of PTSD treatment, individuals with increased suicide risk are unrepresented and outcomes related to suicide are underreported. While many organizations have stated concerns that temporarily increasing distress in exposure treatments, such as PE and CPT, may lead to increased suicidal behaviors in at-risk individuals, there are no studies to support or contradict this concern (Gradus et al., 2013). The two trials of psychotherapy reviewed above suggest that suicidal ideation may decrease during treatment and remain at lower levels following treatment. More research is needed to determine the level of suicide risk at the start of trauma-focused treatment that can be considered safe. Since reducing symptoms of PTSD may reduce future suicidality, it is important not to delay treatment for levels of suicide-risk that can be managed during treatment. Future research should examine a wider range of suicide risk, use more comprehensive measures of suicide, implement and report suicide safety procedures, and include a wider range of trauma types in their samples.
Conclusions and Future Directions
In conclusion, PTSD and suicidality have been reliability shown to have a strong positive relationship. In addition, studies have shown that PTSD is a predictor of future suicidal ideation and attempts (e.g., Panagioti, et al., 2012; Bentley et al., 2016). While depression has been shown to mediate the relationship between PTSD and suicidal ideation (Leitner et al., 2008), the relationship between PTSD and suicidality remains significant when controlling for depression (e.g., Davidson et al., 1991).
Despite the stable relationship between PTSD and suicidality, Bentley et al. (2016) questioned the clinical significance of the relationship. Using the results of their meta-analysis, they demonstrated that when taking the rate of suicide attempts in the US in a given year for adults (0.4%) and multiplying this by 2.25, the increased odds for individuals with PTSD, the probably of a suicide attempt would be 0.9% for the next year. They argue that since the odds of a suicide attempt in the next year are still close to zero, the knowledge of the relationship between PTSD and suicide attempts does not provide meaningful information for clinicians. Since clinicians are generally trying to determine suicide risk for much more immediate time period (e.g., hours, days) and not the following year, Bentley and colleagues (2016) argue that PTSD does not serve as a powerful real-world indicator of risk for suicidal ideation and behaviors. While this critique is valid, it can be argued that clinicians may use the information about the relationship between PTSD and suicidality to increase their assessment of suicidality in patients with PTSD. Similarly, new studies demonstrated that some psychotherapy treatments for PTSD decrease suicidal ideation. These results are promising for upstream suicide prevention suggesting that treating PTSD symptoms may decrease suicidal ideation and suicide risk before risk becomes acute. Future research should focus on the effects of both psychotherapy and pharmacological interventions on suicidal thoughts and behaviors.