Abstract

Introduction

Intermittent explosive disorder (IED) is a disorder characterized by anger outbursts that include destruction of property, and physical and verbal attacks.¹1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Arlington: American Psychiatric Publishing; 2013. This disorder is common, with a 12-month prevalence estimated between 3.1% and 3.9%.²2. Posternak MA, Zimmerman M. Anger and aggression in psychiatric outpatients. J Clin Psychiatry. 2002;63:665-72.,³3. Kessler RC, Coccaro EF, Fava M, Jaeger S, Jin R, Walters E. The prevalence and correlates of DSM-IV intermittent explosive disorder in the National Comorbidity Survey Replication. Arch Gen Psychiatry. 2006;63:669-78. IED is highly impairing due to legal, professional, and social difficulties.¹1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Arlington: American Psychiatric Publishing; 2013.,³3. Kessler RC, Coccaro EF, Fava M, Jaeger S, Jin R, Walters E. The prevalence and correlates of DSM-IV intermittent explosive disorder in the National Comorbidity Survey Replication. Arch Gen Psychiatry. 2006;63:669-78. In Brazil, it may be a relevant contributing factor to high rates of violence.⁴4. Medeiros GC, Leppink E, Seger L, Costa AM, Bernardo C, Tavares H. Impulsive aggression in Brazil: losing opportunities to intervene. Rev Bras Psiquiatr. 2015;37:177-8. However, research in this area is scarce, especially regarding evidence-based interventions.⁵5. McCloskey MS, Noblett KL, Deffenbacher JL, Gollan JK, Coccaro EF. Cognitive-behavioral therapy for intermittent explosive disorder: a pilot randomized clinical trial. J Consult Clin Psychol. 2008;76:876-86.

Several psychotherapeutic approaches to anger management have been published in the literature.⁵5. McCloskey MS, Noblett KL, Deffenbacher JL, Gollan JK, Coccaro EF. Cognitive-behavioral therapy for intermittent explosive disorder: a pilot randomized clinical trial. J Consult Clin Psychol. 2008;76:876-86.,⁶6. DiGiuseppe R, Tafrate RC. Anger treatment for adults: a meta‐analytic review. Clin Psychol Sci Pract. 2003;10:70-84. However, they tend to be general strategies; i.e., there is an important gap on research specifically focusing on the management of IED.⁵5. McCloskey MS, Noblett KL, Deffenbacher JL, Gollan JK, Coccaro EF. Cognitive-behavioral therapy for intermittent explosive disorder: a pilot randomized clinical trial. J Consult Clin Psychol. 2008;76:876-86.,⁶6. DiGiuseppe R, Tafrate RC. Anger treatment for adults: a meta‐analytic review. Clin Psychol Sci Pract. 2003;10:70-84. Excessive anger has been associated with different diagnoses, such as major depressive disorder, anxiety disorders, bipolar disorder, antisocial personality disorder, and borderline personality disorder.¹1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Arlington: American Psychiatric Publishing; 2013. There is some clinical and biological overlap among these conditions associated with problematic aggression.¹1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Arlington: American Psychiatric Publishing; 2013.,⁷7. Galovski T, Blanchard EB. Psychological characteristics of aggressive drivers with and without intermittent explosive disorder. Behav Res Ther. 2002;40:1157-68. Nonetheless, some specific characteristics of IED have been suggested, such as: a) recurrent, brief, unplanned aggression episodes¹1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Arlington: American Psychiatric Publishing; 2013.; b) thought processes associated with perceived injustice⁵5. McCloskey MS, Noblett KL, Deffenbacher JL, Gollan JK, Coccaro EF. Cognitive-behavioral therapy for intermittent explosive disorder: a pilot randomized clinical trial. J Consult Clin Psychol. 2008;76:876-86.; c) very high levels of aggression¹1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Arlington: American Psychiatric Publishing; 2013.,⁷7. Galovski T, Blanchard EB. Psychological characteristics of aggressive drivers with and without intermittent explosive disorder. Behav Res Ther. 2002;40:1157-68.; and d) elevated impatience.¹1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Arlington: American Psychiatric Publishing; 2013.,⁷7. Galovski T, Blanchard EB. Psychological characteristics of aggressive drivers with and without intermittent explosive disorder. Behav Res Ther. 2002;40:1157-68. There is a need for customized treatments focused on specific diagnoses associated with maladaptive anger.⁸8. Glancy G, Saini M. An evidenced-based review of psychological treatments of anger and aggression. Brief Treat Crisis Interv. 2005;5:229. Tailored interventions might increase the efficacy of psychotherapy.

There has only been one published randomized controlled trial of psychotherapy for IED.⁵5. McCloskey MS, Noblett KL, Deffenbacher JL, Gollan JK, Coccaro EF. Cognitive-behavioral therapy for intermittent explosive disorder: a pilot randomized clinical trial. J Consult Clin Psychol. 2008;76:876-86. This study by McCloskey et al. compared 12 weeks of cognitive-behavioral therapy (CBT) delivered in a group format, CBT on an individual basis, or a wait-list control.⁵5. McCloskey MS, Noblett KL, Deffenbacher JL, Gollan JK, Coccaro EF. Cognitive-behavioral therapy for intermittent explosive disorder: a pilot randomized clinical trial. J Consult Clin Psychol. 2008;76:876-86. The results suggested that CBT for IED, either in group or individual format, was effective in reducing aggressive behavior. Group therapy may be particularly effective for IED, as it provides the opportunity to interact with others and practice social/assertive skills, a major issue in IED. Additionally, group therapy tends to be more cost-efficient, which is particularly important in developing countries such as Brazil.

Within this context, we conducted a clinical trial to evaluate the efficacy of a customized manualized group therapy for IED. The therapeutic program was based on cognitive-behavioral techniques and focused specifically on the clinical and neurocognitive characteristics of the disorder. The present report describes the preliminary results of this clinical trial, comparing pre- and post-intervention scores in different anger dimensions.

Methods

Participants

The studied sample consisted of treatment-seeking subjects recruited from the Impulse Control Disorders Outpatient Unit, Institute of Psychiatry, Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP), Brazil. Of the 84 individuals with IED recruited, 59 (70%) completed the intervention. The mean (standard deviation) age was 43.0 (11.9) years, and 78% were male. There was no control group for the study.

Treatment

The therapeutic program consisted of 15 weekly sessions plus three maintenance sessions (Table 1). The sessions, led by two psychologists, lasted approximately 90 minutes each. Patients initially underwent a psychiatric assessment for diagnostic confirmation. Co-occurring psychiatric disorders were previously treated, and patients were enrolled in CBT only after their psychopharmaceutical prescription had remained unchanged for at least a month.

Measures

The State-Trait Anger Expression Scale (STAXI) was used as the outcome variable, and was applied before and after the CBT intervention.⁹9. Spielberger CD. State‐Trait Anger Expression Inventory. New Jersey: John Wiley & Sons; 1999. The STAXI is a 44-question self-report inventory that assesses different anger dimensions. The questionnaire investigates five dimensions (scales) associated with anger: state anger, trait anger, anger expression in, anger expression out, and anger control. The combination of the scales anger expression in, anger expression out, and anger control provides the anger expression score.

Furthermore, the scale trait anger comprises two subscales: temperament and reaction. Each of the 44 items in the STAXI evaluates anger on a four-point Likert scale (1 to 4), where higher scores are associated with more severe anger. The STAXI has been adapted into and validated for use in Brazilian Portuguese.¹⁰10. Biaggio A. Manual do Inventário de Expressão de Raiva como Estado e Traço (STAXI). São Paulo: Vetor; 2003.

Statistical analysis

We used Wilcoxon tests to compare individual participants’ STAXI scores before and after the intervention. Effect sizes (r) were calculated using the formula r = z/√n.¹¹11. Jacobson NS, Truax P. Clinical significance: a statistical approach to defining meaningful change in psychotherapy research. J Consult Clin Psychol. 1991;59:12-9.

Using the normative data for the Brazilian Portuguese STAXI,¹⁰10. Biaggio A. Manual do Inventário de Expressão de Raiva como Estado e Traço (STAXI). São Paulo: Vetor; 2003. we computed the reliable change index. This measure is obtained with the equation: Reliable Change Index = (post-test score − pretest score)/standard error of the difference between the two scores.¹¹11. Jacobson NS, Truax P. Clinical significance: a statistical approach to defining meaningful change in psychotherapy research. J Consult Clin Psychol. 1991;59:12-9. By measuring the reliable change index, we were able to report the percentage of patients who achieved reliable change after treatment.

Results

Subjects who completed treatment (n=59) and dropouts (n=25) were compared. No differences were found in their demographic profiles and pre-treatment status.

Comparison of pre- and post-treatment STAXI scores showed statistically significant changes in all anger scales and subscales of the questionnaire. Figure 1 displays the scores in the different STAXI dimensions before and after the group intervention.

With respect to the percentage of patients achieving reliable change after treatment, the five primary STAXI scales demonstrated the following results: 80.0% for state anger; 100% for trait anger; 41.3% for anger expression in; 93.7% for anger expression out; and 59.9% for anger control.

Discussion

This report presented the preliminary results of a clinical trial of group therapy based on cognitive-behavioral techniques for IED. The intervention demonstrated significantly positive effects on all STAXI anger scales and subscales. With respect to the overall impact of the intervention, the mean (SD) and median r_s for the six anger scales were, respectively, 0.514 (0.199) and 0.566. These r_s are categorized as large (r ≥ 0.5).¹²12. Tucker M, Oei TPS. Is group more cost effective than individual cognitive behaviour therapy? The evidence is not solid yet. Behav Cogn Psychother. 2007;35:77-91. The largest r_s were those associated with trait anger, anger expression out, and anger expression. These dimensions seem to be closely related to the clinical expression of IED, a disorder mainly characterized by maladaptive cognitions and impulsive/outward aggression.¹1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Arlington: American Psychiatric Publishing; 2013. Moreover, the percentage of reliable changes in the scales trait anger and anger expression out after treatment were very high (100.0% and 93.7%, respectively).

In their 2008 study, McCloskey et al. reported moderate effect sizes (mean and median r_s, 0.441±0.114 and 0.459) for pre- and post-intervention scores associated with aggression/anger in subjects who received group CBT. In those who received individual CBT, the authors observed a large effect size for impact on aggression/anger scales (mean and median r_s of, respectively, 0.593±0.114 and 0.601).⁵5. McCloskey MS, Noblett KL, Deffenbacher JL, Gollan JK, Coccaro EF. Cognitive-behavioral therapy for intermittent explosive disorder: a pilot randomized clinical trial. J Consult Clin Psychol. 2008;76:876-86. In this context, the mean and median r_s in our study are slightly higher than those obtained by McCloskey et al. for group CBT.⁵5. McCloskey MS, Noblett KL, Deffenbacher JL, Gollan JK, Coccaro EF. Cognitive-behavioral therapy for intermittent explosive disorder: a pilot randomized clinical trial. J Consult Clin Psychol. 2008;76:876-86. Some factors may explain our better results. First, our group intervention was longer than theirs (18 versus 12 sessions). Second, we added three maintenance sessions, administered every other week after the end of the intervention, to further address relapse prevention, reinforce learned skills, and enhance the “internal psychotherapist.” When compared to individual CBT, the r_s obtained for anger/aggression scores in our group therapy were slightly lower than those obtained with individual therapy in the McCloskey et al. study. Nonetheless, individual CBT is likely less cost-effective than group therapy.¹²12. Tucker M, Oei TPS. Is group more cost effective than individual cognitive behaviour therapy? The evidence is not solid yet. Behav Cogn Psychother. 2007;35:77-91.,¹³13. Vos T, Corry J, Haby MM, Carter R, Andrews G. Cost-effectiveness of cognitive-behavioural therapy and drug interventions for major depression. Aust N Z J Psychiatry. 2005;39:683-92. A comparison between our group intervention and pharmacotherapy revealed similar effect sizes to those of a trial conducted by Coccaro et al. using fluoxetine for subjects with IED.¹⁴14. Coccaro EF, Lee RJ, Kavoussi RJ. A double-blind, randomized, placebo-controlled trial of fluoxetine in patients with intermittent explosive disorder. J Clin Psychiatry. 2009;70:653-62. Their study found r_s between 0.51 and 0.66 for anger/aggression measures.¹⁴14. Coccaro EF, Lee RJ, Kavoussi RJ. A double-blind, randomized, placebo-controlled trial of fluoxetine in patients with intermittent explosive disorder. J Clin Psychiatry. 2009;70:653-62.

Despite the strengths of the current study, the lack of a control group precludes more powerful conclusions, such as whether the observed effects are attributable solely to the CBT intervention. There is a clear need for control/placebo comparisons in future studies approaching group therapy for disorders associated with excessive anger. However, the McCloskey et al. study did not find any response in their control group, which might partially mitigate the uncontrolled design of our intervention.⁵5. McCloskey MS, Noblett KL, Deffenbacher JL, Gollan JK, Coccaro EF. Cognitive-behavioral therapy for intermittent explosive disorder: a pilot randomized clinical trial. J Consult Clin Psychol. 2008;76:876-86.

This preliminary report is a significant addition to the scarce current literature. Our contribution provides further evidence that structured group CBT, with a focus on anger management and cognitive coping, may be a promising approach to the treatment of IED.

Acknowledgements

JEG has received research grants from the National Institute of Mental Health, the National Center for Responsible Gaming, the American Foundation for Suicide Prevention, and the Trichotillomania Learning Center.

References

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