Validity of the new A1 and A2 criteria for DSM-5 intermittent explosive disorder

A latent class analysis of cognitive-affective heterogeneity in current intermittent explosive disorder

Intermittent Explosive Disorder (IED) is a common, chronic, and impairing psychological condition characterized by recurrent, affective aggressive behavior. IED is associated with a host of cognitive and affective symptoms not included in the diagnostic criteria which may be a valuable indicator of heterogeneity in IED-such information can be useful to enhance understanding and treatment of this disorder in mental health settings. A preliminary investigation conducted on cognitive-affective symptom heterogeneity in individuals with a history of IED demonstrated that level of emotional dysregulation primarily differentiated IED subgroups, however the sample size was limited, and almost half of the individuals did not have current IED (only lifetime IED). The present study addressed these limitations by conducting a latent class analysis of cognitive-affective symptoms among a large (n = 504) sample of individuals diagnosed with current IED. The latent IED classes were then externally validated on several adverse outcomes, historical precursors, and demographic variables. Statistical and clinical indicators supported a four-class model, with classes primarily distinguished by patients' severity of emotion dysregulation. The two moderate emotion-dysregulated classes both endorsed callous-unemotional traits and low empathy relative to other classes, a finding which differs from the initial investigation. An external validation of the four classes revealed that they significantly differed on severity outcomes (e.g., aggression, suicide attempts, antisocial behavior, global functioning, comorbidities) and historical precursors (e.g., aversive parental care, childhood maltreatment). These findings provide further insight into the heterogeneity within IED and the associations of such variability with important precursors and clinical outcomes.

Personality Disorder Symptoms in Intermittent Explosive Disorder: A Latent Class Analysis

Intermittent explosive disorder (IED) is characterized by recurrent reactive aggression. IED is associated with significant personality pathology that is suggestive of higher levels of general personality disorder (PD). However, little is known about how personality factors impact the severity and presentation of IED. The present study employed a latent class analysis to assess for distinct PD symptom classes within IED and to evaluate whether these classes differed in terms of severity and behavioral presentation. Statistical and clinical indicators revealed a four-class model, with latent classes distinguished primarily on general levels of PD symptoms (low, moderate, high). However, the two moderate PD symptom classes were distinguished from other classes on avoidant PD. In addition, classes differed in terms of severity and presentation, suggesting important implications for both general PD and avoidant PD comorbidity within IED. Results provide further insight into the heterogeneity within IED and suggest a more nuanced approach in treating this serious condition.

A latent class analysis of intermittent explosive disorder symptoms

Intermittent explosive disorder (IED), the sole diagnosis in the DSM-5 for which the cardinal symptom is recurrent affective aggressive outbursts, is a common and substantially impairing disorder. IED is also associated with several cognitive and affective impairments. However, little is known about the heterogeneity of the disorder and how this may correspond to aggression severity and related adverse outcomes. The current study employed a latent class analysis (LCA) among individuals diagnosed with lifetime DSM-5 IED to derive distinct subgroups that differed in the quality and/or frequency of cognitive-affective symptoms. These subgroups were then externally validated on a number of adverse outcomes. Statistical and clinical indicators supported a four-class model. Classes were distinguished mainly by the level of emotion dysregulation participants endorsed, with two moderate emotion dysregulation classes differing on their emotional information processing and impulsive tendencies. The external validation analysis revealed that classes differed in terms of various adverse outcomes (e.g., interpersonal problems, life satisfaction, suicide risk). Overall, the present study suggests distinct cognitiveaffective symptom profiles among those with IED that differ meaningfully with regard to risk for adverse outcomes. These findings provide evidence of the heterogeneity within IED and may suggest a more personalized therapeutic approach to patients with IED.

Prevalence and psychiatric comorbidities of intermittent explosive disorders in Metropolitan São Paulo, Brazil

PURPOSE

To estimate the prevalence of intermittent explosive disorder (IED) in comorbidity with other psychiatric disorders and to describe the temporal sequencing of disorders in the São Paulo Metropolitan Area, Brazil.

METHODS

Data from the São Paulo Megacity Mental Health Survey, a population-based study of 5037 adult individuals, were analyzed. The World Health Organization Composite International Diagnostic Interview (CID 3.0) was used to assess lifetime DSM-IV disorders, including IED, with a response rate of 81.3%.

RESULTS

The majority (76.8%) of respondents with IED meet the criteria for at least one other psychiatric disorder, with a prevalence almost twice as high as that observed in individuals without IED. The prevalence of any anxiety, mood, impulse control or substance use disorders in respondents with IED was more than two times higher compared to those without IED, with prevalence ratios ranging from 2.1 (95% CI 1.74-2.48) to 2.9 (95% CI 2.12-4.06). The diagnosis of IED occurred earlier than most of the other mental disorders, except for those with usual onset in early childhood, as Specific and Social Phobias and Attention Deficit Disorder.

CONCLUSION

Considering that IED is a highly comorbid disorder and has an earlier onset than most other mental comorbidities in the Brazilian general population, these results may be useful in guiding governmental mental health actions.

Intermittent explosive disorder subtypes in the general population: association with comorbidity, impairment and suicidality

AIMS

Intermittent explosive disorder (IED) is characterised by impulsive anger attacks that vary greatly across individuals in severity and consequence. Understanding IED subtypes has been limited by lack of large, general population datasets including assessment of IED. Using the 17-country World Mental Health surveys dataset, this study examined whether behavioural subtypes of IED are associated with differing patterns of comorbidity, suicidality and functional impairment.

METHODS

IED was assessed using the Composite International Diagnostic Interview in the World Mental Health surveys (n = 45 266). Five behavioural subtypes were created based on type of anger attack. Logistic regression assessed association of these subtypes with lifetime comorbidity, lifetime suicidality and 12-month functional impairment.

RESULTS

The lifetime prevalence of IED in all countries was 0.8% (s.e.: 0.0). The two subtypes involving anger attacks that harmed people ('hurt people only' and 'destroy property and hurt people'), collectively comprising 73% of those with IED, were characterised by high rates of externalising comorbid disorders. The remaining three subtypes involving anger attacks that destroyed property only, destroyed property and threatened people, and threatened people only, were characterised by higher rates of internalising than externalising comorbid disorders. Suicidal behaviour did not vary across the five behavioural subtypes but was higher among those with (v. those without) comorbid disorders, and among those who perpetrated more violent assaults.

CONCLUSIONS

The most common IED behavioural subtypes in these general population samples are associated with high rates of externalising disorders. This contrasts with the findings from clinical studies of IED, which observe a preponderance of internalising disorder comorbidity. This disparity in findings across population and clinical studies, together with the marked heterogeneity that characterises the diagnostic entity of IED, suggests that it is a disorder that requires much greater research.

Subtypes of aggression in intermittent explosive disorder

Research in aggression has distinguished two major subtypes of aggressive behavior: hostile and instrumental. Previous research has examined these subtypes in healthy individuals and forensic samples but not in intermittent explosive disorder (IED), a disorder characterized by recurrent and severe aggressive behavior. We examined aggression subtypes in individuals with IED, healthy subjects, and psychiatric control subjects. We also considered the relationship between aggression subtypes and measures of trait anger and impulsivity to evaluate whether the hostile/instrumental dichotomy adequately captures the heterogeneity of aggressive behavior in this sample. Finally, we consider the implications of these results for research on aggression, including neuroscience research on aggression.

Construct validity and parent-child agreement of the six new or modified disorders included in the Spanish version of the Kiddie Schedule for Affective Disorders and Schizophrenia present and Lifetime Version DSM-5 (K-SADS-PL-5)

Changes to the Diagnostic and Statistical Manual of Mental Disorders fifth edition (DSM-5) incorporate the inclusion or modification of six disorders: Autism Spectrum Disorder, Social Anxiety Disorder, Intermittent Explosive Disorder, Disruptive Mood Dysregulation Disorder, Avoidant/Restrictive Food Intake Disorder and Binge Eating Disorder. The objectives of this study were to assess the construct validity and parent-child agreement of these six disorders in the Spanish language Schedule for Affective Disorders and Schizophrenia for School Age Children Present and Lifetime Version (K-SADS-PL-5) in a clinical population of children and adolescents from Latin America. The Spanish version of the K-SADS-PL was modified to integrate changes made to the DSM-5. Clinicians received training in the K-SADS-PL-5 and 90% agreement between raters was obtained. A total of 80 patients were recruited in four different countries in Latin America. All items from each of the six disorders were included in a factor analysis. Parent-child agreement was calculated for every item of the six disorders, including the effect of sex and age. The factor analysis revealed 6 factors separately grouping the items defining each of the new or modified disorders, with Eigenvalues greater than 2. Very good parent-child agreements (r>0.8) were found for the large majority of the items (93%), even when considering the sex or age of the patient. This independent grouping of disorders suggests that the manner in which the disorders were included into the K-SADS-PL-5 reflects robustly the DSM-5 constructs and displayed a significant inter-informant reliability. These findings support the use of K-SADS-PL-5 as a clinical and research tool to evaluate these new or modified diagnoses.

Prevalence and clinical correlates of intermittent explosive disorder in Turkish psychiatric outpatients

OBJECTIVE

Intermittent explosive disorder (IED) is defined as the failure to resist aggressive impulses resulting in repeated acts of verbal and/or physical aggression. Although it is frequently encountered in clinical psychiatric practice, there is a paucity of data concerning IED in the scientific literature both internationally and in Turkey. The aim of this study was to evaluate the prevalence of IED and associated sociodemographic and clinical features in a clinical setting.

METHODS

A total of 406 patients who were referred to our psychiatry outpatient clinic for the first time in a six-month period were included in the study. The diagnosis of IED was made using both Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) and DSM-5 criteria. Axis I disorder and personality disorder diagnoses were made according to DSM-5 criteria. Diagnoses were based on information from the Structured Clinical Interview for DSM-IV (SCID I) and the Structured Clinical Interview for DSM-IV personality disorders (SCID II), Symptom Checklist-90 (SCL-90), Wender Utah Rating Scale, Adult Attention Deficit Hyperactivity Disorder (ADHD) DSM-IV Based Diagnostic Screening and Rating Scale, a clinical interview conducted by the researcher, and a sociodemographic data form. In addition, participants were administered the Buss-Perry Aggression Scale and Barratt Impulsiveness Scale Version 11 (BIS-11) to assess aggression and impulsivity.

RESULTS

Lifetime and 12-month prevalence of IED according to DSM-5 were 16.7% and 11.3%, respectively. Mean age at onset was 16.4 years. The prevalence of lifetime IED was 3.8 times higher in males than females (95% CI = 1.9-7.5); twice as high in individuals living in rural areas compared to those living in urban centers (95% CI = 1.1-3.7); 2.7 times higher among those with lifetime suicide attempt versus those without (95% CI = 1.3-5.6); 4.5 times higher in those with lifetime self-injurious behavior compared to those without (95% CI = 2.3-8.7); and 3 times higher in individuals reporting aggression/anger problems in the family compared to those without (95% CI = 1.5-5.9). The prevalences of childhood ADHD, conduct disorder, and oppositional defiant disorder were significantly higher in the IED group.

CONCLUSION

The result of the current study has revealed that approximately one-sixth of respondents experienced lifetime IED according to DSM-5 diagnostic criteria. Statistically significant sociodemographic correlates of IED include gender, urbanicity, history of suicide attempt, history of self-injurious behavior, and family history of aggression/anger problems.

Trait anger modulates neural activity in the fronto-parietal attention network

Anger is considered a unique high-arousal and approach-related negative emotion. The influence of individual differences in trait anger on the processing of visual stimuli is relevant to questions about emotional processing and remains to be explored. Using functional magnetic resonance imaging (fMRI), we explored the neural responses to standardized images, selected based on valence and arousal ratings in a group of men with high trait anger compared to those with normative to low anger scores (controls). Results show increased activation in the left-lateralized ventral fronto-parietal attention network to unpleasant images by individuals with high trait anger. There was also a group by arousal interaction in the left thalamus/pulvinar such that individuals with high trait anger had increased pulvinar activation to the high-arousal (versus low arousal) unpleasant images as compared to controls. Thus, individual differences in trait anger in men are associated with brain regions subserving executive attentional and sensory integration during the processing of unpleasant emotional stimuli, particularly to high arousal images.

Intermittent Explosive Disorder and Substance Use Disorder: Analysis of the National Comorbidity Survey Replication Sample

OBJECTIVE

A relationship between aggression and substance use has been debated for many years. While substance use increases the risk of aggressive behavior, no studies have reported on the relationship between impulsive aggression and substance use/disorder, specifically.

METHODS

We analyzed data from the community-based National Comorbidity Survey Replication (N = 9,282 subjects) in order to examine the relationship between current DSM-5 intermittent explosive disorder (IED), a disorder of impulsive aggression, and current substance use disorders (SUDs), overall, and with regard to alcohol, tobacco, and cannabis use disorders and nondisordered use.

RESULTS

Occurrence of current SUD was elevated in current IED versus non-IED adult subjects, and onset of IED preceded that of SUD in 92.5% of comorbid IED + SUD cases. This relationship was not due to the presence, or absence, of current depressive or anxiety disorders. Examination of the severity of IED and of SUD revealed that the presence of IED increases SUD severity but that the presence of SUD does not increase IED severity.

CONCLUSIONS

Subjects with IED are at increased risk of developing SUD, compared with those without IED. This suggests that history of recurrent, problematic, impulsive aggression is a risk factor for the later development of SUD rather than the reverse. If so, effective treatment of impulsive aggression, before the onset of substance misuse, may prevent, or delay, the development of SUD in young people.

Development of a screening questionnaire for DSM-5 intermittent explosive disorder (IED-SQ)

OBJECTIVE

This study was designed to develop and test a screening approach to identify individuals with DSM-5 Intermittent Explosive Disorder (IED), a disorder of recurrent, problematic, impulsive aggression.

METHODS

A screening approach to diagnose DSM-5 IED (IED-SQ) was developed by combining items related to life history of aggression and items related to the DSM-5 diagnostic criteria for IED. In study 1, the IED-SQ was studied in 72 adult participants; 33 that met DSM-5 criteria for lifetime IED and 39 that did not. In study 2, the IED-SQ was given to 740 undergraduates at a US university. Measures of aggression and anger expression and anger control were assessed in both studies.

RESULTS

In study 1, the IED-SQ demonstrated strong concordance with the best estimate diagnoses (Kappa =.80) for lifetime IED by DSM-5 criteria and good test-retest reliability (kappa =0.71). In study 2, the IED-SQ identified 4.3% of the undergraduate sample as meeting DSM-5 criteria for lifetime IED, a rate comparable to that in recent epidemiological studies. Participants identified as meeting DSM-5 criteria for lifetime IED, in both studies, had higher aggression scores, and higher anger expression, and lower anger control scores, compared to participants that did not meet DSM-5 criteria for lifetime IED.

CONCLUSIONS

These data suggest that the IED-SQ is a useful screening tool that can quickly identify the presence of IED by DSM-5 criteria in adults.

The cross-national epidemiology of DSM-IV intermittent explosive disorder

BACKGROUND

This is the first cross-national study of intermittent explosive disorder (IED).

METHOD

A total of 17 face-to-face cross-sectional household surveys of adults were conducted in 16 countries (n = 88 063) as part of the World Mental Health Surveys initiative. The World Health Organization Composite International Diagnostic Interview (CIDI 3.0) assessed DSM-IV IED, using a conservative definition.

RESULTS

Lifetime prevalence of IED ranged across countries from 0.1 to 2.7% with a weighted average of 0.8%; 0.4 and 0.3% met criteria for 12-month and 30-day prevalence, respectively. Sociodemographic correlates of lifetime risk of IED were being male, young, unemployed, divorced or separated, and having less education. The median age of onset of IED was 17 years with an interquartile range across countries of 13-23 years. The vast majority (81.7%) of those with lifetime IED met criteria for at least one other lifetime disorder; co-morbidity was highest with alcohol abuse and depression. Of those with 12-month IED, 39% reported severe impairment in at least one domain, most commonly social or relationship functioning. Prior traumatic experiences involving physical (non-combat) or sexual violence were associated with increased risk of IED onset.

CONCLUSIONS

Conservatively defined, IED is a low prevalence disorder but this belies the true societal costs of IED in terms of the effects of explosive anger attacks on families and relationships. IED is more common among males, the young, the socially disadvantaged and among those with prior exposure to violence, especially in childhood.

Reward vs. Retaliation-the Role of the Mesocorticolimbic Salience Network in Human Reactive Aggression

The propensity for reactive aggression (RA) which occurs in response to provocation has been linked to hyperresponsivity of the mesocorticolimbic reward network in healthy adults. Here, we aim to elucidate the role of the mesocorticolimbic network in clinically significant RA for two competing motivated behaviors, reward-seeking vs. retaliation. 18 male participants performed a variant of the Point-Subtraction Aggression Paradigm (PSAP) during functional magnetic resonance imaging (fMRI). We examined whether RA participants compared with non-aggressive controls would choose to obtain a monetary reward over the opportunity to retaliate against a fictitious opponent, who provoked the participant by randomly stealing money from his earnings. Across all fMRI-PSAP runs, RA individuals vs. controls chose to work harder to earn money but not to retaliate. When engaging in such reward-seeking behavior vs. retaliation in a single fMRI-PSAP run, RA individuals exhibited increased activation in the insular-striatal part of the mesocorticolimbic salience network, and decreased precuneus and ventromedial prefrontal cortex activation compared to controls. Enhanced overall reward-seeking behavior along with an up-regulation of the mesocorticolimbic salience network and a down-regulation of the default-mode network in RA individuals indicate that RA individuals are willing to work more for monetary reward than for retaliation when presented with a choice. Our findings may suggest that the use of positive reinforcement might represent an efficacious intervention approach for the potential reduction of retaliatory behavior in clinically significant RA.

Effects of oxytocin on aggressive responding in healthy adult men

This study investigated the acute effects of oxytocin (OT) on human aggression using a well-established laboratory measure of state (reactive) aggression to test the hypothesis that OT would decrease the frequency of aggressive responding. In a within-subject design, 17 healthy male volunteers received placebo or 24 IU of intranasal OT. Aggression was measured using the Point Subtraction Aggression Paradigm at 30 min before and 30, 60, and 90 min after dose. Acute OT did not produce a significant main effect on aggressive behavior. OT attenuated the expected rise in diastolic blood pressure from morning to early afternoon observed under placebo, providing a possible indication of biological activity. Examination of individual differences showed that aggressive responding following OT dosing (but not placebo) was positively correlated with psychometric measures of interpersonal manipulation and anger (Pearson's r=0.57), indicating that higher scores on these antisocial personality traits were related to increased aggressive behavior following OT administration. These preliminary results stand in contrast to previous work on the prosocial effects of OT and highlight the need for further understanding of individual differences in aggression following OT administration. Such individual differences may have implications for the therapeutic use of OT in individuals with psychiatric disorders and dysfunctional social behavior.

Amygdala hyperactivation to angry faces in intermittent explosive disorder

BACKGROUND

Individuals with intermittent explosive disorder (IED) were previously found to exhibit amygdala hyperactivation and relatively reduced orbital medial prefrontal cortex (OMPFC) activation to angry faces while performing an implicit emotion information processing task during functional magnetic resonance imaging (fMRI). This study examines the neural substrates associated with explicit encoding of facial emotions among individuals with IED.

METHOD

Twenty unmedicated IED subjects and twenty healthy, matched comparison subjects (HC) underwent fMRI while viewing blocks of angry, happy, and neutral faces and identifying the emotional valence of each face (positive, negative or neutral). We compared amygdala and OMPFC reactivity to faces between IED and HC subjects. We also examined the relationship between amygdala/OMPFC activation and aggression severity.

RESULTS

Compared to controls, the IED group exhibited greater amygdala response to angry (vs. neutral) facial expressions. In contrast, IED and control groups did not differ in OMPFC activation to angry faces. Across subjects amygdala activation to angry faces was correlated with number of prior aggressive acts.

CONCLUSIONS

These findings extend previous evidence of amygdala dysfunction in response to the identification of an ecologically-valid social threat signal (processing angry faces) among individuals with IED, further substantiating a link between amygdala hyperactivity to social signals of direct threat and aggression.

Effects of Escitalopram Administration on Face Processing in Intermittent Explosive Disorder: An fMRI Study

The neurobiological underpinnings of intermittent explosive disorder (IED) are traditionally linked to deficiencies in the serotonergic system. In this study, we investigated the effects of escitalopram, a selective serotonin reuptake inhibitor (SSRI), on brain activation during face processing. We expected that escitalopram would reduce amygdala activity in IED and in addition, we explored the effect in other social-emotional-related brain regions. A total of 17 subjects with current IED and 14 healthy controls participated in a randomized, double-blind, placebo-controlled, counterbalanced fMRI face processing study. The analysis focused on the faces compared to a fixation baseline contrast, and a factorial model with Group as between-subject and Drug as within-subject factor was tested. Group × Drug interaction effects were found in the amygdala (small volume corrected) and the left temporal parietal junction (TPJ; whole-brain corrected). Escitalopram increased amygdala activation in controls, but surprisingly not in IED. However, the TPJ showed increased activity in IED on escitalopram compared with placebo. The TPJ is associated with social-cognitive processes, such as perspective taking and empathy. The TPJ findings suggest that SSRI administration may reduce aggressive tendencies towards other people by enhancing these social-cognitive processes. Future research should further elucidate the long-term effects of SSRIs on various social-emotional tasks in IED.

Emotional intelligence and impulsive aggression in Intermittent Explosive Disorder

Emotional intelligence (EI) relates to one's ability to recognize and understand emotional information and then, to use it for planning and self-management. Given evidence of abnormalities of emotional processing in impulsively aggressive individuals, we hypothesized that EI would be reduced in subjects with Intermittent Explosive Disorder (IED: n = 43) compared with healthy (n = 44) and psychiatric (n = 44) controls. The Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) was used to assess both Experiential EI and Strategic EI. Strategic, but not Experiential, EI was lower in IED compared with control subjects. These differences were not accounted for demographic characteristics, cognitive intelligence, or the presence of clinical syndromes or personality disorder. In contrast, the relationship between IED and Strategic EI was fully accounted for by a dimension of hostile cognition defined by hostile attribution and hostile automatic thoughts. Interventions targeted at improving Strategic EI and reducing hostile cognition will be key to reducing aggressive behavior in individuals with IED.