Pathways from childhood trauma to suicidal ideation: mediating through difficulties in emotion regulation and depressive symptoms

Suicide is a serious health concern globally. Over 700,000 deaths are reported worldwide per annum, with male suicides outnumbering female suicides, and the bulk of suicides occur in low- and middle-income countries (LMICs), where the majority of the world's population live [1]. The global lifetime prevalence of suicidal ideation (SI) and suicide attempts is 9.2% and 2.7%, respectively [1, 2]. Additionally, it is expected that for every individual who dies by suicide, there are more than 20 others who have attempted suicide, and for every person who attempts suicide, there are two to three others who seriously consider it but do not go through with an attempt [3]. The magnitude and seriousness of this public health issue have prompted a significant surge in research investigating SI. Nevertheless, the rate of suicide has not yet diminished [4]. Precise prediction is critical for efficient prevention. As a result, a major focus of suicide research has been on identifying risk factors for SI. Despite this major research concentration, research in this area remains predominately focused on high-income countries, with little research addressing SI in LMICs [5]. The current study, therefore, focuses on the associations between childhood trauma (ChT), depressive symptoms, difficulties in emotion regulation (DER), SI, and gender in an LMIC– Iran.

Suicidal ideation (i.e., having transitory to comprehensive and lingering thoughts of suicide) is recognized as a significant harbinger of subsequent suicide attempts and fatality [6]. SI is among the most significant risk factors for suicide [7], which, without intervention, leads one-third of ideators to attempt suicide [8]. Furthermore, SI has been associated with poor psychological adjustment and functioning, as well as subsequent depressive syndromes [9, 10]. Several theories explain the emergence course of SI. Of relevance to this study, the integrated motivational-volitional model (IMV; [11]) posits that when certain distal risk factors, such as ChT, are present, an individual may be prone to developing SI [12]. Motivational and threat-to-self variables, such as DER [13], are proposed to play a mediating role between this pre-existing susceptibility (i.e., childhood trauma) and risk for SI. Also, depression has been claimed to be one of the strongest predictors of SI (e.g., [14]), which is in close association with both DER [15] and ChT [16].

Childhood trauma, such as parental neglect or physical, sexual, and emotional abuse, are key predisposing risk factors for SI [17]. Several studies have found strong links between childhood sexual, physical, and emotional abuse and SI [18, 19]. According to a recent meta-analysis, all types of ChT are linked to a two- to three-fold greater risk of SI [20]. The links between certain ChT, depressive symptoms, and SI have also been recognized [21]. ChT accelerates the onset of major depressive disorder and worsens its prognosis and severity across the lifespan [22], which is of import as depression is one of the most widely reported risk factors for SI [23].

Moreover, those who have experienced ChT are more likely to have DER, which in turn increases proneness to depressive symptoms [24, 25], which is also regarded as Achilles' heel to SI [26]. According to theories of suicide (e.g., suicide as psychache, Three-Step Theory (3ST)), psychological pain (i.e., psychache) is a major contributor to SI [27, 28] and the capacity for emotion regulation (i.e., the ability to monitor, appraise, and modulate emotional experiences and responses) is an important aspect of managing this pain [29]. There are various theories and frameworks for emotion regulation; nevertheless, integrating research through a shared conceptualization would most probably result in a greater cross-fertilization of outcomes between emotion scientists and the psychopathologies [30]. Thus, in the current study, we chose Gratz and Roemer's [29] emotion regulation and dysregulation paradigm because of its considerable applicability to clinical and psychopathologic contexts. Accordingly, being aware and cognizant of emotions, accepting emotions, having the ability of impulse control and goal-directed behavior in the face of negative emotions, and having the capacity to employ context-pertinent emotion regulation strategies toward individual goals and situational demands, conceptualized as emotion regulation and the lack of each of abovementioned features is defined as difficulties in emotion regulation.

Emotion regulation/dysregulation appears to play an essential role in explaining SI in etiological models (i.e., Interpersonal Theory of Suicide (IPTS) and 3ST) of suicidal processes [28, 31]. In these models, emotion regulation strategies have been regarded as precedents/prohibitors of SI. Both the 3ST and the IPTS imply that perceptions of oneself as detached from others, a burden on others, and high levels of psychological pain are related to failed emotional coping strategies [28, 31]. As a result, studies have frequently indicated that emotional regulation impairments accelerate the development of the SI (e.g., [32]). Also, according to the IMV model, defeat/humiliation perceptions resulting in the sense of entrapment are fundamental to the motivational phase of SI development [12]. Feelings of entrapment as a result of negative self-appraisals reinforce the belief that suicide is the only way out [33].

While several studies have identified risk factors for SI [34‐37], further research is needed to examine the direct and indirect associations between theorized risk factors and SI. As noted above, it is theoretically posited that ChT raises the likelihood of SI. Theoretically and empirically, it has been argued that variables, such as emotion regulation and mood disorders, may play a mediating role between this pre-existing susceptibility (i.e., childhood trauma) and SI [13, 34, 38, 39]. There is accumulating empirical support for these theoretical accounts. For instance, Mohammadzadeh et al. [40] found among males who use heroin that, while ChT had no direct effect on SI, ChT was indirectly associated with SI through some emotion regulation difficulties. Roley‐Roberts and colleagues found that facets of emotion dysregulation mediated the associations between child sexual abuse and SI [41]. Hatkevich et al. [42] found among adolescent inpatients that limited access to emotion regulation strategies, difficulties in impulse control, and mood disorder diagnosis were significantly associated with past-year SI. Hatkevich et al. [43] demonstrated that emotional abuse might be differentially related to experiencing limited access to emotion regulation strategies at the level indicative of SI risk. Thus, SI may stem from ChT and, subsequently, the emotional dysregulation [40]. Additionally, Hopfinger and colleagues found that general emotion regulation deficits mediated the association between ChT and both depression severity and depression lifetime persistency [25]. Their findings support the theoretical assumption that DER may play a role in the negative course of depression in those who have experienced ChT.

Therefore, based on theoretical accounts and previous findings that emotion regulation deficits mediate the association between ChT and depression (e.g., [25]), and depression is then associated with SI [44], we propose that it is possible that there is an indirect pathway between ChT and SI through DER and depressive symptoms. Despite accumulating research investigating these associations and theoretically proposed pathways between ChT and SI, an important significant gap in SI research is that much of the research has been conducted in Western cultural contexts and high-income countries. Consequently, there has been an identified need for greater research in LMICs (e.g., [5]). This is particularly important as the majority of suicides occur in LMICs [1]. The current study, therefore, focused on Iran, a country with the highest increase in suicide-related deaths among Islamic countries and the Eastern Mediterranean region [45]. Additionally, research indicates that culture impacts processes such as emotion regulation [46, 47], known to be associated with SI [48], and Iranian researchers have called for greater research exploring the factors contributing to SI and suicide in Iran [49]. Finally, as there is an identified need for national policies and interventions in Iran to target the prevention of suicide, it is critical that risk factors for SI are investigated in Iranian samples [34, 45]. Thus, this study is novel in investigating these associations and pathways that have been found in other cultural contexts in an Iranian sample.

Finally, in the SI literature, gender disparities in suicide susceptibility have not been well addressed [50]. Emerging research aims to highlight possible gender variations in suicide risk vulnerability (i.e., behavior and ideation). In the instance of Iran, higher suicide attempt rates have been found among women, while higher suicide mortality rates have been found among men [49]. Kiadaliri and colleagues [49] suggest several potential explanations for these gender differences, including a) methods of attempting suicide, whereby men in Iran commonly use hanging and firearms, which have higher fatality rates compared with the self-burning method commonly used by women, b) greater psychosocial impact of problems, such as unemployment or retirement, on men compared with women, and c) men adopting coping strategies such as emotional inexpressiveness, lack of help-seeking, risk-taking behavior, violence, and substance use. They also highlight, therefore, the importance of including gender analyses in suicide research, as such information is important for designing and implementing suicide prevention strategies. Moreover, SI has been at the vanguard of suicide research in attempting to understand these gender differences [51]; consequently, investigations targeted at understanding gender differences are critical, and including an examination of gender-specific associations between the study variables are of potential importance.

The bivariate correlations between ChT, depressive symptoms, DER, and SI are presented in Table 1. As evident in Table 1, all bivariate correlations were significant, which showed that all endogenous and exogenous indicators were associated (except physical abuse and cognitive subscale of depression, r = 0.07). As a result, it can be said that the conceptual model that has been provided has solid conceptual and statistical underpinnings for investigating the mediation model. (Figs. 1, 2 and 3 and Table 2).

The aim of the present study was to explore the mediation pathways from ChT to SI through depressive symptoms and DER. In support of hypothesis 1, ChT had significant positive associations with depressive symptoms and DER. Second, depressive symptoms and DER were significantly associated with SI (hypothesis 2). Extant literature shows that the association found between ChT and depressive symptoms is consistent with the extensive previous literature (e.g., [76]). In the context of ChT, parents can be emotionally unavailable, children can experience chronic interpersonal stress (rejection and stifled social support), and children can form insecure attachments, factors all associated with adulthood depression [80, 81]. Our finding that depressive symptoms were directly associated with SI aligns with strong evidence indicating that depression is one of the most widely reported risk factors for SI [, , , 3, 23, 44, 82]. Additionally, ChT had a significant direct association with DER. Kim and Cicchetti [83], in a longitudinal study, reported ChT, specifically emotional neglect and physical and sexual abuse, were related to difficulties in emotion regulation. Individuals with ChT, when compared to those without a history of ChT, used less adaptive emotion regulation strategies. Thus, ChT appears to play a crucial role in developing poor emotion regulation strategies [84].

Regarding hypothesis 3, our findings revealed interesting mediation effects. First, we found that neither DER nor depressive symptoms have mediated the association between ChT and SI solely. These results seem counterintuitive at first glance. Nevertheless, when we inspected more closely, we discovered that DER and depressive symptoms function together (in a sequential path) in the theory-adaptive sequence to mediate the association between ChT and SI. This finding reveals a more complex, comprehensive, and interpretative association between distal and proximal associations between ChT and SI. Our model results indicate that ChT, without taking into account DER, is not explaining depressive symptoms and SI. But in a more composite and inclusive panorama, ChT can contribute to depressive symptoms and then SI in the mere existence and presence of DER. This finding fits within the framework of transdiagnostic theories of emotion regulation, namely the heuristic model of emotion regulation [85]. The authors postulated that a combination of proximal (endophenotype) and distal (traumatic experience, genetic proneness) factors would cause inflexible emotion regulation (e.g., rumination) to initiate a variety of externalizing and internalizing disorders. In our study’s setting, ChT can act as the distal factor leading to more proximal risk factors (i.e., DER) and finally lead toward depressive symptoms and SI as a manifestation of depression or as an experiential avoidance strategy [86] used to shy away from all psychache [27, 87] imposed by ChT and depressive states. This finding immaculately confirms Mohammadzadeh et al.s’ [40] findings in which they found that ChT was not directly linked to SI; it was indirectly linked to SI through DER. Intriguingly, in a longitudinal study with a sizable sample (i.e., 5423), Wu et al. [39] found that in a mediation model, emotion reactivity (an index of DER) leads to depression, and depression leads to SI, which is precisely consistent with our findings and model. Consistently and particularly, Hatkevich et al. [43] researched different forms of childhood abuse and found that compared to other forms of abuse and neglect, emotional abuse may be more strongly associated with having restricted access to emotion regulation strategies during adolescence, which is a condition suggestive of a higher risk of SI. Demirci also reported associations between childhood sexual abuse, DER, and diverse psychiatric conditions [88]. Other studies also are indicative of associations between ChT, depression, and suicidal behavior [89, 90]. Individuals who have experienced ChT have a lower activation threshold as well as a broader spectrum of internal and external triggers for SI. Indeed, a trauma-related image or thought can precipitate a crisis, operate as a forerunner, and cause unpleasant affective states and emotions that can lead to suicidal behavior [91]. Hatkevich et al. [42] also observed that DER and a diagnosis of a mood disorder were all linked to SI in the previous year. As parents/caregivers play a critical role in structuring, elaborating, and regulating a child's emotions [92], children exposed to trauma (e.g., physical abuse, emotional neglect) may, in turn, perceive the world as unpredictable and threatening and others (particularly parents) are not emotionally available to provide required structure and regulation of emotions [83]. This unavailability would increase the DER and also increases the possibility of psychopathology, peer rejection [93], and interpersonal difficulties [94], leading to self-mutilative thoughts and behaviors, including SI.

Historically, identifying those most vulnerable to SI and attempts has been challenging; the huge number of possible risk variables has made such predictions inaccurate [95]. Clinicians need to have a thorough awareness of the risk factors for suicide and how they combine to increase the risk of suicide. The present study's findings have important therapeutic relevance to clinical and clinical analogue populations since the variables assessed (i.e., depressive symptoms, DER, and ChT) have been shown to play a role in SI. This is the first time such variables and pathways have been investigated in Iran. This is of relevance in Iran, where the need for policies and interventions targeting the prevention of suicide has been identified [34]. Thus, the findings indicate that such targets may have applicability in Iran and may help to assess suicide risk levels more accurately.

The current study examined direct and indirect associations between SI-related variables in the proposed conceptual model, and there was a significant indirect effect of ChT on SI through DER and depressive symptoms. Despite that our study was a cross-sectional study, it was able to cost-efficiently replicate the findings of large-scale longitudinal investigations (e.g., [38, 39]). There are important clinical implications that may be inferred from the mediation path that our study identified. Nearly 40% of participants in the World Mental Health (WMH) initiative in 21 countries reported having traumatic childhood experiences [102]. Concerning this high prevalence, concentrating on the emotion regulation intervention (e.g., [103]) in particular can be a sensible preventive strategy that may buffer against the enduring effects of ChT while also reducing depressive symptomatology and, ultimately, diminishing SI and behavior.