سابقه بدرفتاری در دوران کودکی در اختلال انفجاری متناوب و رفتار خودکشی

Intermittent Explosive Disorder (IED) is a relatively common disorder of impulsive aggression that typically emerges by adulthood. Maltreatment in childhood (CM) may contribute to the development of IED, but little is known about the association between CM and IED, including about how subtypes of CM may specifically relate to IED. This study aimed to test the association between CM and IED diagnosis. A second aim was to examine history of CM in suicide attempters, and to explore whether impulsivity and aggression account for the relationship between CM and suicide attempt (SA). Adults with Intermittent Explosive Disorder (IED; n = 264), with non-IED psychiatric (Axis I or II) disorders (psychiatric controls; PC; n = 199), and with no psychiatric disorder (healthy control subjects; HC; n = 185) were assessed for history of childhood maltreatment, aggression, impulsivity, and history of SA. IED subjects reported significantly greater CM compared to PC and HC subjects, and suicide attempters (n = 62) reported greater CM compared to non-attempters (n = 586). Physical abuse in childhood was independently associated with IED, while sexual abuse and emotional abuse were independently associated with SA. Impulsivity and aggression were potential mediators of the relationship between physical abuse and IED and emotional abuse and SA, but sexual abuse was associated with SA independently of aggression and impulsivity. The results suggest pathways by which environmental factors may influence impulsivity and aggression and, in turn, clinically significant self- and other-directed aggression.

Aggression and suicide are destructive behaviors that exact a considerable toll on individuals, families, and society. Each year, approximately 1.6 million people die as a result of violence, both self- and other-directed (WHO, 2009), and these events and other non-lethal forms of aggression (i.e., interpersonal assaults and suicide attempts) have substantial economic costs (Czernin et al., 2012; WHO, 2004). Despite the severity of these behaviors they are relatively common. In the National Comorbidity Study (NCS), 4.6% of respondents reported making a suicide attempt in their lifetime (Kessler et al., 1999), while the lifetime prevalence of clinically significant aggression, as defined by Intermittent Explosive Disorder (IED) DSM-IV criteria, was reported as high as 7.3% (Kessler et al., 2006). Impulsive aggression is the core feature of IED and is also a risk factor for suicidal behavior, making it an important target of efforts to reduce both self- and other-directed aggressive behavior. Behavioral genetics studies indicate that both genetic and environmental factors contribute to the development of aggression (Coccaro et al., 1997a, Miles and Carey, 1997 and Yeh et al., 2010); however, relatively little is known about environmental variables which may contribute to the development of clinically significant impulsive aggression (IED). Understanding the factors that promote the development of impulsivity and aggression (and which may in turn increase the likelihood of suicide attempt and persistent aggression) is thus an important scientific and therapeutic goal. One set of environmental circumstances that has been shown to contribute to the development of impulsive aggression is childhood maltreatment (CM). CM includes experiences of physical, emotional, and sexual abuse, and emotional and physical neglect. CM predicts a range of negative outcomes, including psychopathology (Briere and Elliott, 2003, Green et al., 2010, Lobbestael et al., 2010 and Scott et al., 2012), aggression (Singer et al., 1999; Song et al., 1998), and suicidal behaviors (Miller et al., 2013 and Silverman et al., 1996), but little is known specifically about the role of CM in the development of IED. Individuals with IED have been found to have significant histories of trauma (e.g., accidents, disaster-related traumas; Fincham, 2011), and interpersonal traumas and traumas experienced early in life are particularly predictive of IED (Nickerson et al., 2012), suggesting that CM may significantly increase the risk of developing IED. Furthermore, childhood adversities related to a maladaptive family environment have been shown to be particularly predictive of later psychopathology in general (Green et al., 2010 and McLaughlin et al., 2012). Studies on the effects of CM on suicidality suggest that most forms of CM increase the risk of suicide attempt when considered separately (Miller et al., 2013), but that sexual, physical, and emotional abuse are particularly robust predictors when different forms of CM are considered together in multivariate analyses (Beautrais et al., 1996, Hacker et al., 2006, Joiner et al., 2007 and Ystgaard et al., 2004). In addition to being a core feature of IED, impulsive aggression is also associated with Antisocial Personality Disorder (ASPD) and Borderline Personality Disorder (BPD). Further, suicide attempters and completers have been found to have higher levels of impulsivity and aggression (Brodsky et al., 2001, Dumais et al., 2005 and Mann et al., 1999). Brodsky (2001) examined childhood abuse history, BPD, and impulsive and aggressive personality traits as predictors of lifetime suicide attempt. Participants reporting a history of childhood abuse were more likely to have attempted suicide, had higher reported levels of impulsivity and aggression, and were more likely to meet criteria for BPD. However, when considered together, childhood abuse, but not BPD, impulsivity, or aggression, contributed uniquely to the prediction of SA. The purpose of this study was to examine the associations between early experiences of abuse and neglect and clinically significant aggressive and self-aggressive behavior in an adult sample of research volunteers with and without psychopathology. We first sought to extend prior research on the association between trauma and IED by using a well-validated measure of childhood maltreatment that distinguishes different forms of CM including physical and sexual abuse and neglect. Specifically, we compared participants with IED to non-IED psychiatric control subjects (PC) and healthy control (HC) subjects on subtypes of CM and total CM. Next, we examined which forms of childhood maltreatment were independently associated with impulsive and aggressive traits, and with a lifetime diagnosis of IED. Finally, we explored impulsivity and aggression as potential mediators of the relationship between CM and IED. We conducted similar analyses for lifetime history of suicide attempt. This was done to replicate and extend prior findings by examining potential specific associations between type of childhood abuse and suicide attempt as well as the roles of impulsivity and aggression in these relationships. These relationships were tested in a series of hierarchical models. In order test whether these effects were independent of Antisocial and Borderline Personality Disorders, as these are associated with impulsive aggression, suicide risk, and early life trauma (Beautrais et al., 1996, Brodsky et al., 2001, Lobbestael et al., 2010 and Silverman et al., 1996), we included these diagnoses as covariates in a final logistic regression model. We predicted that: 1) IED subjects would report more childhood maltreatment compared with healthy control and psychiatric control subjects; 2) subjects with history of suicide attempt would report more CM and have higher scores on aggression and impulsivity; and 3) trait aggression and impulsivity (assessed dimensionally) would at least partially explain the relationship between CM and later IED and SA, suggesting that CM may increase impulsivity and aggressiveness and thereby increase the risk of negative outcomes.