Lifetime and 1-month prevalence rates of intermittent explosive disorder in a community sample

OBJECTIVE: To determine the lifetime and 1-month prevalence of intermittent explosive disorder (IED) by both DSM-IV and research criteria in a community sample. METHOD: The final 253 (34.1%) of individuals who were entered into the Hopkins Epidemiology Study of Personality Disorder and sampled in the context of a follow-up study of participants from the Baltimore Epidemiologic Catchment Area (ECA) study completed a supplemental interview that allowed for the determination of IED by DSM-IV and/or research criteria. RESULTS: The mean +/- SE percentage of subjects who met inclusion criteria was 11.07% +/- 1.97%, and 6.32% +/- 1.53% met full criteria, for lifetime IED by either diagnostic criteria set; 2.37% +/- 0.96% met full criteria for IED within the previous 1 month. Adjusting the prevalence rates to account for differential sampling from the original ECA study did not substantially affect these results. Onset of problematic aggressive behavior in IED subjects (described as lifelong in most subjects) began as early as childhood, peaked in the third decade, and declined steadily after the fifth decade. While distress and/or impairment due to aggressive behavior was documented in 87.5% of IED subjects, only 12.5% of IED subjects reported seeking help for this problem. CONCLUSIONS: Intermittent problematic aggressive behavior in the community, as defined by IED, may be far more common than previously thought. Conservatively estimated, the number of individuals in the United States with IED, based on these data, may be no lower than 1.4 million for current IED or nearly 10 million for lifetime IED.     

Metoprolol for intermittent explosive disorder

Metoprolol, a selective beta 1-adrenoreceptor blocker, was administered to two patients with intermittent explosive disorder who had not done well with previous medications, including propranolol and carbamazepine. Both patients improved dramatically, suggesting clinical and theoretical relevance.     

Lifetime and 12-month prevalence of bipolar spectrum disorder in the National Comorbidity Survey replication

CONTEXT: There is growing recognition that bipolar disorder (BPD) has a spectrum of expression that is substantially more common than the 1% BP-I prevalence traditionally found in population surveys. OBJECTIVE: To estimate the prevalence, correlates, and treatment patterns of bipolar spectrum disorder in the US population. DESIGN: Direct interviews. SETTING: Households in the continental United States. PARTICIPANTS: A nationally representative sample of 9282 English-speaking adults (aged >or=18 years). MAIN OUTCOME MEASURES: Version 3.0 of the World Health Organization's Composite International Diagnostic Interview, a fully structured lay-administered diagnostic interview, was used to assess DSM-IV lifetime and 12-month Axis I disorders. Subthreshold BPD was defined as recurrent hypomania without a major depressive episode or with fewer symptoms than required for threshold hypomania. Indicators of clinical severity included age at onset, chronicity, symptom severity, role impairment, comorbidity, and treatment. RESULTS: Lifetime (and 12-month) prevalence estimates are 1.0% (0.6%) for BP-I, 1.1% (0.8%) for BP-II, and 2.4% (1.4%) for subthreshold BPD. Most respondents with threshold and subthreshold BPD had lifetime comorbidity with other Axis I disorders, particularly anxiety disorders. Clinical severity and role impairment are greater for threshold than for subthreshold BPD and for BP-II than for BP-I episodes of major depression, but subthreshold cases still have moderate to severe clinical severity and role impairment. Although most people with BPD receive lifetime professional treatment for emotional problems, use of antimanic medication is uncommon, especially in general medical settings. CONCLUSIONS: This study presents the first prevalence estimates of the BPD spectrum in a probability sample of the United States. Subthreshold BPD is common, clinically significant, and underdetected in treatment settings. Inappropriate treatment of BPD is a serious problem in the US population. Explicit criteria are needed to define subthreshold BPD for future clinical and research purposes.     

Hypothalamic lesions and intermittent explosive disorder.

The authors present two cases of patients with craniopharyngiomas who meet the DSM-III-R criteria for intermittent explosive disorder. Episodes of rage developed before and/or after surgery for removal of the craniopharyngioma. Magnetic resonance imaging revealed hypothalamic-hypophyseal involvement. It is suggested that hypothalamic lesions played a major role in the development of aggressive behavior in both cases.     

The prevalence and correlates of intermittent explosive disorder in Iraq

Al‐Hamzawi A, Al‐Diwan JK, Al‐Hasnawi SM, Taib NI, Chatterji S, Hwang I, Kessler RC, McLaughlin KA. The prevalence and correlates of intermittent explosive disorder (IED) in Iraq. Objective: Intermittent explosive disorder is common, begins early in life, and is associated with considerable impairment in the United States. The epidemiology of IED outside the United States is unknown. We examined the prevalence and correlates of IED in Iraq, where exposure to violence has been widespread during the last three decades. Method: Data were drawn from a national survey of the Iraq population, the Iraq Mental Health Survey (IMHS), conducted in 2006–2007. The WHO Composite International Diagnostic interview was used to assess DSM‐IV disorders, including IED. The response rate was 95.2%. Results: Lifetime and 12‐month prevalence estimates of IED were 1.7% and 1.5%. Mean age of onset was 18.5. The mean number of lifetime attacks was 141.6 attacks, and IED‐related injuries occurred 61 times per 100 lifetime cases. IED was significantly comorbid with mood and anxiety, but not substance, disorders. Conclusion: Although the prevalence of IED is lower in Iraq than in the United States, the disorder has an early age of onset, is highly persistent, and is associated with substantial comorbidity and functional impairment. Iraq lacks national policies or systematic programmes to reduce aggression, highlighting the importance of implementing violence prevention programmes to reduce the societal burden of violence in Iraq.     

Amygdala hyperactivation to angry faces in intermittent explosive disorder

BackgroundIndividuals 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.MethodTwenty 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.ResultsCompared 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.ConclusionsThese 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.     

EEG correlates of moderate intermittent explosive disorder.

OBJECTIVE: We investigated electroencephalographic (EEG) correlates of moderate intermittent explosive disorder (mIED), which is characterized by uncontrollable, impulsive attacks that either manifest in aggressive outbursts of temper, or in implosive, auto-aggressive behaviour. METHODS: In two Experiments, EEG data were recorded during rest conditions, and while subjects were presented with auditory and visual stimuli. Additionally, scores of the I7 impulsivity scale (designed to capture acting on impulse) were obtained. RESULTS: In Experiment 1, individuals with mIED showed a stronger increase in the power of oscillatory activity in the beta band, along with a stronger power decrease in the theta band in response to both visual and auditory stimuli. Based on discriminant function analysis, a model of discriminant functions was derived that clearly separated the mIED group from the control group. In Experiment 2, subjects were categorized into either of two groups (supposedly without mIED, with mIED) based on this model of discriminant functions. Results showed that I7 impulsivity scores clearly differed between groups. CONCLUSIONS: The present data show a relation between oscillatory brain activity and mIED. They indicate that this brain activity is related to the impulsivity facet of impulsive action, and suggest that mIED can be assessed based on the analysis of electrophysiological data. SIGNIFICANCE: To our knowledge, this is the first study on EEG correlates of (m)IED. Results open up new perspectives for future investigations on disorders characterized by substantial impulsivity.     

A family history study of intermittent explosive disorder

Background

Intermittent Explosive Disorder (IED) is newly appreciated as a commonly occurring disorder of impulsive aggression. Since aggression and impulsivity are under genetic influence, IED may be familial.

Methods

Blinded and controlled family history study of IED and co-morbid conditions in an outpatient clinical research center for impulsive aggression. The subjects were first-degree relatives of individuals who did and did not meet criteria for IED by DSM-IV and Research Criteria.

Results

Elevated Morbid Risk of IED was observed in relatives of IED Probands compared with relatives of Non-IED Probands. This familial signal of IED was not affected by comorbidity in the IED Probands of comorbidity in the relatives of the IED Probands.

Conclusions

IED, as defined by research criteria, appears to be familial and may not be an artifact of other co-morbid conditions.     

Prevalence and features of intermittent explosive disorder in a clinical setting

OBJECTIVE: To determine the lifetime and current prevalence, along with other characteristics such as age at onset, patterns of comorbidity, and interest in treatment, of DSM-IV intermittent explosive disorder (IED) in an outpatient psychiatric sample. METHOD: 1300 individuals presenting for outpatient psychiatric treatment at Rhode Island Hospital, Providence, R.I., underwent structured diagnostic assessment for Axis I and II disorders. The diagnosis of IED was made according to DSM-IV criteria. RESULTS: 6.3% (SE, +/- 0.7%) of patients met criteria for lifetime DSM-IV IED, and 3.1% +/- 0.5% of patients met criteria for current DSM-IV IED. While DSM-IV IED was the current principal diagnosis in only 0.6% +/- 0.2% of patients, most patients with current DSM-IV IED (80%) were interested in treatment for their intermittent aggressive behavior. Only lifetime alcohol/drug disorder was more frequent in DSM-IV IED compared with non-IED patients. Age at onset for DSM-IV IED peaked in the teen years, was earlier for men than women, and occurred earlier than all comorbid disorders, with the exception of phobic anxiety disorders, suggesting that IED cannot be attributed to most comorbid conditions. CONCLUSIONS: DSM-IV IED in psychiatric samples is far more common than previously thought. DSM-IV IED develops early in life, especially in male patients, and its development may be independent of most other disorders.     

Latent structure of intermittent explosive disorder in an epidemiological sample

Intermittent explosive disorder (IED) is characterized by distinct periods of impulsive aggression marked by assaultive acts or destruction of property. However, impulsive aggression is also a feature of other disorders, all of which are viewed in diagnostic nomenclature as qualitatively distinct from IED. This state of affairs is problematic for categorical models unless it is demonstrated empirically that IED-related impulsive aggression is qualitatively distinct from impulsive aggression observable in other axis I and II disorders. The current study addresses this question using taxometric methods to examine the latent structure of IED. Participants were respondents on the Collaborative Psychiatric Epidemiological Surveys, which obtained data on a range of disorders including intermittent explosive disorder (N = 20,013) and a range of psychological variables. Indicator variables used were drawn from the survey items and submitted to select taxometric methods (MAMBAC and MAXEIG) to determine the relative fits of a taxonic versus dimensional model. The results of taxometric analyses provided support for a taxonic, rather than dimensional, structure for IED symptoms in the epidemiological sample. Taxon group membership was associated with treatment seeking, family history of anger attacks, lower age of onset of anger attacks, and male biological sex, providing strong support for the validity of the IED taxon.     

Proton magnetic resonance spectroscopy of bipolar disorder versus intermittent explosive disorder in children and adolescents

OBJECTIVE: The diagnosis of bipolar disorder in juveniles is controversial. This study was designed to compare proton magnetic resonance spectroscopy ((1)H MRS) in patients with bipolar disorder or intermittent explosive disorder, two groups with symptomatic overlap but categorical distinction. Children with intermittent explosive disorder designate patients whose illness clinically resembles pediatric bipolar disorder but does not satisfy DSM-IV criteria for mania. Based on the authors' previous report of higher levels of (1)H MRS cingulate myo-inositol/creatine in youngsters with bipolar disorder than in normal comparison subjects, they hypothesized that patients with bipolar disorder would have higher cingulate myo-inositol/creatine-phosphocreatine measurements than patients with intermittent explosive disorder and normal comparison subjects. METHOD: Myo-inositol levels were measured with a 2x2x2 cm(3) voxel placed in the anterior cingulate for acquisition of (1)H MRS in 10 patients with bipolar disorder, 10 patients with intermittent explosive disorder, and 13 normal comparison subjects. N-Acetylaspartate, choline moieties, creatine-phosphocreatine, and glutamate-glutamine metabolite levels were also measured. RESULTS: The patients with bipolar disorder showed significantly higher anterior cingulate myo-inositol/creatine-phosphocreatine and myo-inositol (mmol/liter) levels than the patients with intermittent explosive disorder and the normal comparison subjects. No significant differences were found across groups for myo-inositol or other metabolites in the occipital cortex. CONCLUSIONS: These data provide evidence that differences in the concentration of myo-inositol (mmol/liter) in the anterior cingulate cortex in (1)H MRS may differentiate these two populations. Follow-up studies involving larger samples may conclusively estimate the biological specificity between pediatric bipolar disorder and other disorders, which overlap clinically.     

Striatal activity in borderline personality disorder with comorbid intermittent explosive disorder: sex differences

Borderline Personality Disorder (BPD) is associated with behavioral and emotional dysregulation, particularly in social contexts; however, the underlying pathophysiology at the level of brain function is not well understood. Previous studies found abnormalities in frontal cortical and limbic areas suggestive of poor frontal regulation of downstream brain regions. However, the striatum, which is closely connected with the medial frontal cortices and plays an important role in motivated behaviors and processing of rewarding stimuli, has been understudied in BPD. Here we hypothesized that, in addition to frontal dysfunction, BPD patients may show abnormal striatal function. In this study, 38 BPD patients with intermittent explosive disorder (BPD-IED) and 36 healthy controls (HC) participated in the Point Subtraction Aggression Paradigm (PSAP), a computer game played with a fictitious other player. (18)Fluoro-deoxyglucose positron emission tomography (FDG-PET) measured relative glucose metabolism (rGMR) within caudate and putamen in response to aggression-provoking and non-provoking versions of the PSAP. Male BPD-IED patients had significantly lower striatal rGMR than all other groups during both conditions, although male and female BPD-IED patients did not differ in clinical or behavioral measures. These sex differences suggest differential involvement of frontal-striatal circuits in BPD-IED, and are discussed in relation to striatal involvement in affective learning and social decision-making.     

The relationship between childhood exposure to trauma and intermittent explosive disorder

There has been a paucity of research linking intermittent explosive disorder (IED) to trauma and posttraumatic stress responses, despite evidence that trauma is strongly associated with anger reactions. The present study investigated the relationship between IED and a number of trauma-related factors, including trauma dosage, timing of first trauma, and posttraumatic stress disorder (PTSD). Participants were 4844 trauma-exposed and 731 non trauma-exposed adults who took part in the National Comorbidity Survey-Replication (NCS-R). Findings indicated that IED was associated with greater trauma exposure, PTSD and generalized anxiety disorder (GAD) diagnosis, and first exposure to traumatic events in childhood. Exploratory analyses investigating the link between IED and age at first trauma exposure across trauma types suggested that IED is related to childhood exposure to interpersonal traumatic events. These findings are discussed in the context of developmental trauma and cycles of violence models.     

Self-harm behavior among individuals with intermittent explosive disorder and personality disorders

Self-harm behaviors are a major public health concern across the lifespan, particularly among individuals with psychiatric disorders. Little research, however, has examined these behaviors among individuals with a diagnosis characterized by recurrent acts of impulsive aggression, Intermittent Explosive Disorder (IED). Furthermore, extant research has not examined variables that might mediate the relationship between IED and self-harm. The current study examined the rates of non-suicidal self-injury (NSSI) and suicide attempts among individuals with IED as compared to healthy controls, individuals with personality disorders (PDs; which are highly comorbid with IED), and individuals with comorbid IED and PD. The study also examined the indirect effects of aggression, impulsivity, and affective lability in the relationship between diagnosis and self-harm. Participants were 1079 community individuals and prevalence rates among the total sample were 18% for NSSI and 13.2% for suicide attempts. Scores on measures aggression, impulsivity, and affect lability showed significant indirect effects on the relationships between IED + PD and NSSI; scores on aggression showed a significant indirect effect on the relationship between PD and NSSI; scores on impulsivity showed a significant indirect effect on the relationship between IED + PD and suicide attempt. These results suggest that individuals with PDs, and particularly those with comorbid IED and PD, are at increased risk for engagement in self-harm behaviors. Furthermore, traits of aggression, impulsivity, and affect lability significantly accounted for the relationship between diagnostic status and self-harm, particularly in regards to NSSI.     

Lifetime and 12-month prevalence of DSM-IV psychiatric disorders among Korean adults

The objective was to estimate the prevalence and correlates of psychiatric disorders in a nationwide sample of Korean adults. Face-to-face interviews were conducted with the Korean version of Composite International Diagnostic Interview 2.1/DSM-IV (N = 6275, response rate 79.8%). The lifetime and 12-month prevalences for all types of DSM-IV disorders were 33.5% and 20.6%, respectively. Those of specific disorders were as follows: 17.2% and 7.1% for alcohol use disorder, 11.2% and 7.4% for nicotine use disorder, 5.2% and 4.2% for specific phobia, 4.3% and 1.7% for major depressive disorder, and 2.3% and 1.0% for generalized anxiety disorder. Among the sociodemographic variables, widowed status, higher income, and rural residence were the risk factors for both lifetime major depressive disorder and alcohol use disorder after controlling for gender, age, and education. The prevalence of psychiatric disorders was higher than those observed in other East-Asian countries and most European countries, but lower than that in the United States. Alcohol use disorder was particularly high in Korea.     

Prevalence of suicidal and self-injurious behavior among subjects with intermittent explosive disorder

The prevalence of suicidal attempts and self-injurious behavior among 376 subjects diagnosed with Intermittent Explosive Disorder (IED) was assessed via structured interviews. Results showed 16% of IED subjects reported self-aggression, with 12.5% reporting suicide attempts and 7.4% reporting non-lethal self-injurious behaviors. Additional risk factors were identified.     

Comorbid intermittent explosive disorder and posttraumatic stress disorder: Clinical correlates and relationship to suicidal behavior

ObjectivePosttraumatic stress disorder (PTSD) is associated with both aggressive and suicidal behavior. Recent research suggests that the diagnosis of intermittent explosive disorder (IED), an impulse-control disorder characterized by repeated impulsive aggressive behavior, may help to identify individuals at risk for attempting suicide. Given the relationship between anger and PTSD, there is likely to be an increased prevalence of IED among individuals with PTSD; however, little is known about the overlap in these two disorders, including how individuals with comorbid IED and PTSD may differ from those with either disorder alone. The purpose of this study is to examine the clinical correlates of comorbid IED and PTSD and the contribution of these two disorders (among others) to lifetime suicide attempt and characteristics of suicidal behavior.MethodIn a large sample of community research volunteers (N = 1460), we compared individuals with PTSD, IED, and comorbid PTSD and IED on measures of current mood, trait aggression, and trait impulsivity. We also examined the contributions of PTSD, IED, and other syndromal and personality disorders to the prediction of lifetime aggression and lifetime suicide attempt, and their relationship to characteristics of suicide attempts, including level of intent, use of violent versus non-violent means, and the medical seriousness of the attempt.ResultsComorbid PTSD and IED was associated with significantly elevated levels of depression, anxiety, anger, aggression, and impulsivity, as well as with high rates of comorbidity with other psychiatric disorders. IED (β = .56, p < .001), but not PTSD, significantly and uniquely predicted lifetime aggressive behavior. Both IED and PTSD were associated with lifetime suicide attempt in multivariate analysis (ORs: 1.6 and 1.6, ps < .05). The results show that IED, when comorbid with PTSD, identifies a subgroup of individuals with particularly high levels of aggressive behavior and a high rate of suicide attempt (41.4% in this sample).ConclusionThese findings add support to the notion that the diagnosis of IED may aid in identifying individuals at risk for aggressive and suicidal behavior.