Future Directions: The Phenomenology of Irritable Mood and Outbursts: Hang Together or Hang Separately1.

Recognition of the importance of irritable mood and outbursts has been increasing over the past several decades. This "Future Directions" aims to develop a set of recommendations for future research emphasizing that irritable mood and outbursts "hang together," but have important distinctions and thus also need to "hang separately." Outbursts that are the outcome of irritable mood may be quite different from outbursts that are the trigger or driving force that make youth and his/her environment miserable. What, then, is the relation between irritable mood and outbursts? As the field currently stands, we not only cannot answer this question, but we may also lack the tools to effectively do so. Here, we will propose recommendations for understanding the phenomenology of irritable mood and outbursts so that more directed and clinically useful assessment tools can be designed. We discuss the transdiagnostic and treatment implications that relate to improvements in measurement. We describe the need to do more than repurpose our current assessment tools, specifically interviews and rating scales, which were designed for different purposes. The future directions of the study and treatment of irritable mood and outbursts will require, among others, using universally accepted nomenclature, supporting the development of tools to measure the characteristics of each irritable mood and outbursts, understanding the effects of question order, informant, development and longitudinal course, and studying the ways in which outbursts and irritable mood respond to treatment.

Art therapy masks reflect emotional changes in military personnel with PTSS.

Among disabling post-traumatic stress symptoms (PTSS) are irritability, aggressive behavior, distressing memories and general impaired cognition and negative mood. Art therapy interventions, including mask-making, can potentially alleviate these symptoms. We tested the hypothesis that art conveys emotions and predicted that blinded viewers would be able to perceive changes in theoretically derived emotional profiles expressed in art made by military personnel with PTSS from the onset to the end of therapy. Five service members and veterans exhibiting PTSS were enrolled in an 8-session art therapy protocol, during which they artistically transformed papier-mâché masks at the beginning and end of the protocol. We found that blinded viewers without knowledge of the masks' creation stage (onset or end of therapy) read initial masks as conveying more negative emotions (e.g., angry, upset, and challenged) and later masks as conveying more positive emotions (calm and pleasure). Based on the assessments from the blinded evaluators, we infer the emotional transition experienced by the participants was expressed in the masks. In an exploratory arm of the study, we also found that viewers were better able to empathize with the negative emotions experienced by participants with PTSS when asked to explicitly take their perspective.

What I see, what you say: How cross-method variation sharpens characterization of irritability in early childhood.

OBJECTIVES: Identification of clinically significant irritability in preschool age is important to implement effective interventions. However, varying informant and measurement methods display distinct patterns. These patterns are associated with concurrent and future mental health concerns. Patterns across multi-informant methods in early-childhood irritability may have clinical utility, identifying risk for impaired psychosocial functioning. METHODS: Using data from the Multidimensional Assessment of Preschoolers Study (N = 425), latent profile analysis identified irritability patterns through the parent-reported Multidimensional Assessment Profile Scales-Temper Loss (MAPS-TL), parent-reported interviewer-rated Preschool Age Psychiatric Assessment (PAPA), and observer-rated Disruptive Behavior Diagnostic Observation Schedule (DB-DOS). These profiles were characterized on protective factors, global functioning, and mental health syndromes, concurrently and at early school age and preadolescent follow-up. RESULTS: Fit indices favored a five-class model: Low All, High Observation with Examiner (high DB-DOS Examiner Context), High All, High Parent Report (high MAPS-TL/PAPA), and Very High Parent Report (very high MAPS-TL/PAPA). Whereas Low All and High Observation with Examiner exhibited strong psychosocial functioning, remaining profiles showed impaired psychosocial functioning, with the Very High Parent Report group showing higher impairment at follow-ups, ds = 0.37-1.25. CONCLUSIONS: Multi-informant measurements of irritability may have utility for clinical prediction, and future studies should test utility for diagnostic precision.

Dysphoria as trans-diagnostic mood symptom and as lived experience. Lessons from prose, poetry and philosophy.

This paper attempts to provide a characterisation of it from a first-person perspective of dysphoria, answering the question 'how it feels like to be dysphoric?'. Starting with a definition of emotions as embodied phenomena that provide the person with a felt motivation to move, a rich characterisation of dysphoria is provided centred on the coenesthetic and kinesthetic feelings inherent to this emotion. To fulfil this task, a selected choice of literary, poetic, theatrical and philosophical texts is used to compensate for the quasi-ineffability of the contrasting feelings inherent to dysphoria. Current definitions of dysphoria only highlight the 'negative' side of dysphoria, including irritability, discontent, surrender and interpersonal resentment. A more accurate characterisation necessitates the recognition of the 'positive' side of dysphoria and the ambiguities and contradictions inherent in this emotion. Dysphoric persons feel burdened by a weight that prevents them from moving and simultaneously incites movement. The inertia that accompanies dysphoria is inextricably tied in with a vital urge, however disordered and purposeless. Dysphoria is experienced both as a deadly stagnation and as a chaotic, wild impulse that brings with it an inane aspiration to explore the darkest parts of one's self in search of a glimmer of meaning and authenticity. This characterisation of dysphoria can help to differentiate it from other emotions such as sadness, anger, anxiety and anguish, and thus to identify it more precisely within the spectrum of mood disorders.

Substance use disorders in adults with attention-deficit/hyperactivity disorder: The role of affective temperament.

OBJECTIVE: Substance Use Disorders (SUD) are common in adults with Attention-Deficit/Hyperactivity Disorder (ADHD). Although predictors of SUD in this population are relevant for prevention and treatment, they need further clarification. Affective temperaments potentially associated with SUD in adult ADHD patients were explored. METHODS: ADHD patients with and without SUD were compared for sociodemographic, clinical, and psychological characteristics through: Adult ADHD Self-Report Scale; Wender Utah Rating Scale; Temperament Evaluation Memphis for Pisa, Paris, and San Diego-Autoquestionnaire. Logistic regression investigated factors associated with SUD. RESULTS: We included one-hundred and thirty-six ADHD patients with (n = 51, 37.5 %) and without SUD (n = 85, 62.5 %). The presence of SUD was associated with irritable temperament (p = 0.009), as well as more frequent school failure (p = 0.038), legal problems (p = 0.039), and lifetime suicide attempts (p = 0.014). LIMITATIONS: The cross-sectional design, the relatively small sample size, and the use of self-administered questionnaires. CONCLUSIONS: This study confirms the greater overall severity of adult ADHD-SUD compared with ADHD-only patients and suggests the potential role of irritable temperament as a predictor of substance-related problems.

Irritability across adolescence: Examining longitudinal trajectory, stability, and associations with psychopathology and functioning at age 18.

BACKGROUND: Irritability, marked by diminished frustration tolerance, holds significant implications for youth mental health treatment. Despite prior research on irritability trajectories, understanding of individual differences during adolescence remains limited. This study examines the stability and trajectory of irritability across ages 12-18, investigating associations with psychopathology and functioning at age 18. METHODS: A community sample of families with 3-year-old children (N = 518) was recruited via commercial mailing lists. Irritability was assessed at ages 12, 15, and 18 using the Affective Reactivity Index. Psychopathology at age 18 was evaluated with the Kiddie Schedule for Affective Disorders and Schizophrenia, and functioning was assessed through the UCLA Life Stress Interview. Measurement invariance analyses and latent growth curve modeling were conducted within a structural equation modeling (SEM) framework. RESULTS: Configural, metric, and scalar invariance models were supported. Elevated irritability at age 12 predicted adverse outcomes at age 18, including increased psychotropic medication use, mental health treatment, suicidal ideation, self-injury, and psychiatric disorders. Importantly, these associations persisted even after accounting for corresponding variables at age 12. The trajectory of irritability during early adolescence significantly predicted heightened risks for various outcomes at age 18, including suicidal ideation, depression, anxiety, disruptive behavior disorders, and impaired interpersonal functioning. DISCUSSION: Limitations include using only youth-reported data at age 18, limited generalizability from a mostly White, middle-class sample, and insufficient exploration of the broader developmental trajectory of irritability. Nevertheless, the findings emphasize the crucial role of irritability's trajectory in influencing various psychopathological and functional outcomes in late adolescence.

Key psychosocial issues in medical care.

OBJECTIVE: The aim of this review is to illustrate an innovative framework for assessing the psychosocial aspects of medical disorders within the biopsychosocial model. It is based on clinimetrics, the science of clinical measurements. It may overcome the limitations of DSM-5 in identifying highly individualized responses at the experiential, behavioral, and interpersonal levels. METHOD: A critical review of the clinimetric formulations of the biopsychosocial model in the setting of medical disease was performed. References were identified through searches from PubMed for English articles on human subjects published from January 1982 to October 2023. RESULTS: Clinimetric methods of classification have been found to deserve special attention in four major areas: allostatic load (the cumulative cost of fluctuating and heightened neural or neuroendocrine responses to environmental stressors); health attitudes and behavior; persistent somatization; demoralization and irritable mood. This type of assessment, integrated with traditional psychiatric nosography, may disclose pathophysiological links and provide clinical characterizations that demarcate major prognostic and therapeutic differences among patients who otherwise seem deceptively similar because they have the same medical diagnosis. It may be of value in a number of medical situations, such as: high level of disability or compromised quality of life in relation to what is expected by disease status; delayed or partial recovery; insufficient participation in self-management and/or rehabilitation; failure to resume healthy role after convalescence; unhealthy lifestyle; high attendance of medical facilities disproportionate to detectable disease; lack of treatment adherence; illness denial. CONCLUSIONS: The clinimetric approach to the assessment of key psychosocial variables may lead to unique individual profiles, that take into account both biology and biography. It may offer new opportunities for integrating psychosocial and medical perspectives.

Irritability in Youths: A Critical Integrative Review.

Irritability, defined as proneness to anger that may impair an individual's functioning, is common in youths. There has been a recent upsurge in relevant research. The authors combine systematic and narrative review approaches to integrate the latest clinical and translational findings and provide suggestions for addressing research gaps. Clinicians and researchers should assess irritability routinely, and specific assessment tools are now available. Informant effects are prominent, are stable, and vary by age and gender. The prevalence of irritability is particularly high among individuals with attention deficit hyperactivity disorder, autism spectrum disorder, and mood and anxiety disorders. Irritability is associated with impairment and suicidality risk independent of co-occurring diagnoses. Developmental trajectories of irritability (which may begin early in life) have been identified and are differentially associated with clinical outcomes. Youth irritability is associated with increased risk of anxiety, depression, behavioral problems, and suicidality later in life. Irritability is moderately heritable, and genetic associations differ based on age and comorbid illnesses. Parent management training is effective for treating psychological problems related to irritability, but its efficacy in treating irritability should be tested rigorously, as should novel mechanism-informed interventions (e.g., those targeting exposure to frustration). Associations between irritability and suicidality and the impact of cultural context are important, underresearched topics. Analyses of large, diverse longitudinal samples that extend into adulthood are needed. Data from both animal and human research indicate that aberrant responses to frustration and threat are central to the pathophysiology of irritability, revealing important translational opportunities.

Neural Responses to Intranasal Oxytocin in Youths With Severe Irritability.

OBJECTIVE: The authors investigated the neural impact of intranasal oxytocin on emotion processing areas in youths with severe irritability in the context of disruptive mood and behavior disorders. METHODS: Fifty-two participants with severe irritability, as measured by a score ≥4 on the Affective Reactivity Index (ARI), with diagnoses of disruptive behavior disorders (DBDs) and/or disruptive mood dysregulation disorder (DMDD) were randomly assigned to treatment with intranasal oxytocin or placebo daily for 3 weeks. Assessments were conducted at baseline and at the end of the trial; the primary outcomes were measures of irritability on the ARI and ratings on the Clinical Global Impressions severity scale (CGI-S) focusing on DBD and DMDD symptoms, and secondary outcomes included the CGI improvement scale (CGI-I) and ratings of proactive and reactive aggressive behavior on the Reactive-Proactive Aggression Questionnaire. Forty-three participants (22 in the oxytocin group and 21 in the placebo group) completed pre- and posttreatment functional MRI (fMRI) scans with the affective Stroop task. RESULTS: Youths who received oxytocin showed significant improvement in CGI-S and CGI-I ratings compared with those who received placebo. In the fMRI data, blood-oxygen-level-dependent (BOLD) responses to emotional stimuli in the dorsomedial prefrontal cortex and posterior cingulate cortex were significantly reduced after oxytocin compared with placebo. These BOLD response changes were correlated with improvement in clinical severity. CONCLUSIONS: This study provides initial and preliminary evidence that intranasal oxytocin may induce neural-level changes in emotion processing in youths with irritability in the context of DBDs and DMDD. This may lead to symptom and severity changes in irritability.

Study Preregistration: Understanding the Etiology of Externalizing Problems in Young Children: The Roles of Callous-Unemotional Traits and Irritability.

Externalizing behavioral problems in young children are associated with later delinquency and crime,1 which can cause burdens at both personal and socialeconomic levels. The heterogeneity of externalizing problems emphasizes the importance of examining the etiological mechanisms that underlie externalizing problems and related behaviors. The present study focuses on 2 risk factors for externalizing behavioral problems in early childhood: callous-unemotional traits (CU), characterized as a lack of guilt and empathy,2 and irritability, a tendency to show anger and frustration.3 Behavioral genetic studies find that externalizing problems, CU, and irritability are heritable,4,5 raising the possibility of common genetic effects linking the 3 behaviors, but this has not been previously explored. Neurological evidence suggests distinct pathways from CU and irritability to externalizing problems,6 implying that the genetic and environmental factors linking externalizing problems and CU may differ from those linking externalizing problems and irritability. We predict that there will be common genetic influences operating across externalizing problems, CU, and irritability; but we also predict unique genetic and environmental influences representing distinctive risks shared between externalizing problems and CU, and between externalizing problems and irritability, respectively.

Psychopharmacology Management in Autism Spectrum Disorder.

Persons with autism spectrum disorder (ASD) may have other psychiatric conditions that warrant treatment. Symptoms may not be easy to discern from rigidity or irritability that are sometimes considered to be constituent parts of ASD. Pathophysiology that involves hyperexcitable neurons and anomalous connectivity may provide justification for using psychopharmacologic agents, although nonmedical strategies may also be effective. Hyperactivity, irritability, and tantrums with or without aggression may be rational targets for psychopharmacological intervention. The best-studied drug class to date has been the second-generation antipsychotics targeting irritability.

Paternal postnatal depression and parenting behaviours in the first year of life.

BACKGROUND: Paternal postnatal depression (PPD) symptomology has been positively associated with poorer outcomes for children. One mechanism by which PPD is thought to influence child outcomes is through parenting. The current study investigated the association between paternal postnatal depressive symptoms and parenting behaviours. METHOD: Fathers (N = 213) with an infant (mean age = 7 months, 46% female) between 2 and 12 months old were recruited through community and social media advertisements, as well as a paid survey recruitment website. Fathers completed a questionnaire on their symptoms of PPD and how they care for and raise their child (parental warmth, irritability, engagement in enrichment, play and safety behaviours). RESULTS: Fathers experiencing greater levels of PPD symptomatology self-reported higher irritability, lower warmth and fewer safe parenting behaviours but did not report lower enrichment or play with their infants. CONCLUSION: Overall, findings suggest that PPD symptomology may impact negatively on aspects of fathers' parenting behaviours. Further research using larger and more diverse samples is needed to assess the generalisability of these findings.

Neuropsychiatric symptoms of dementia in those with and without a recorded history of psychological trauma: A comparative study from an Australian dementia support service.

OBJECTIVE: To compare the number and severity of neuropsychiatric symptoms (NPS) and associated caregiver distress between those with and without a noted history of psychological trauma among those referred to a specialised national dementia NPS support service. METHODS: This was a 5-year retrospective observational study of records from the Dementia Support Australia NPS support service. NPS were reported by formal or informal caregivers at service entry using the Neuropsychiatric Inventory Nursing Home version or Questionnaire version. A history of psychological trauma was recorded in the person's social or medical history and/or endorsed as a contributor to NPS by a trained dementia consultant after a comprehensive clinical review. Regression was used to examine the impact of a recorded history of psychological trauma on NPS severity and associated caregiver distress, controlling for age and sex. RESULTS: Among 41,876 eligible referrals with dementia, 6% (n = 2529) had some reference in their records to a history of psychological trauma. Referrals with a recorded history of psychological trauma were rated with a higher rate of both NPS severity (mean = 12.0) and associated caregiver distress (mean = 16.5) at service entry than those without a recorded history of psychological trauma (means = 10.7 and 14.5, respectively). A recorded history of psychological trauma was associated with higher odds of psychotic symptoms, agitation/aggression, irritability, disinhibition, affective symptoms and night-time behaviours. CONCLUSIONS: Traumatic stress symptoms may represent a neglected target for intervention to reduce the impact of NPS in people with dementia.

The longitudinal relationship between socioemotional difficulties and irritability in ADHD.

BACKGROUND: Despite higher rates of irritability and socioemotional symptoms in ADHD, consensus is lacking regarding their developmental relationship and whether it differs by ADHD status. This longitudinal study sought to evaluate how peer and emotional difficulties relate to irritability in ADHD and control groups. METHODS: A community sample of 336 participants (45 % ADHD) were recruited for the Children's Attention Project. Participants completed the Affective Reactivity Index and the Strengths and Difficulties Questionnaire's emotional and peer difficulties scales at baseline (mean age 10.5 years) and 18-month follow-up. Latent Change Score models assessed how emotional and peer difficulties related to irritability at baseline and longitudinally. RESULTS: For both groups, more severe baseline difficulties were associated with higher concurrent irritability, and reductions in emotional and peer difficulties were associated with declining irritability. Baseline emotional difficulties predicted change in irritability for the ADHD group, while baseline peer difficulties predicted change in irritability for both groups. Baseline irritability did not predict change in emotional or peer difficulties for either. The ADHD group showed elevated irritability, emotional, and peer difficulties, and stronger baseline correlation between peer difficulties and irritability. LIMITATIONS: Only two timepoints were captured, and associations with ADHD symptom severity and presentation were not investigated. Doing so may facilitate additional insights. CONCLUSIONS: Change in irritability corresponded to change in socioemotional difficulties, and was driven by earlier levels of socioemotional difficulties. ADHD exacerbated aspects of the relationship between socioemotional difficulties and irritability. Socioemotional difficulties drive irritability, so may represent targets for clinical interventions.

Novel Assessment of the Impact of Irritability on Physiological and Psychological Frustration Responses in Adolescents.

OBJECTIVE: Irritability, typically defined as a proneness to anger, particularly in response to frustration, falls at the intersection of emotion and disruptive behavior. Despite well-defined translational models, there are few convergent findings regarding the pathophysiology of irritability. Most studies utilize computer-based tasks to examine neural responses to frustration, with little work examining stress-related responding to frustration in social contexts. The present study is the first to utilize the novel Frustration Social Stressor for Adolescents (FSS-A) to examine associations between adolescent irritability and psychological and physiological responses to frustration. METHOD: The FSS-A was completed by a predominantly male, racially, ethnically, and socioeconomically diverse sample of 64 12- to 17-year-olds, who were originally recruited as children with varying levels of irritability. Current irritability was assessed using the Multidimensional Assessment Profiles-Temper Loss scale (MAP-TL-Youth). Adolescents rated state anger and anxiety before and after the FSS-A, and usable salivary cortisol data were collected from 43 participants. RESULTS: Higher MAP-TL-Youth scores were associated with greater increases in anger during the FSS-A, but not increases in anxiety, or alterations in cortisol. Pre-task state anger negatively predicted the slope of the rise in cortisol observed in anticipation of the FSS-A. CONCLUSIONS: Results provide support for unique associations between adolescent irritability and anger during, and in anticipation of, frustrating social interactions. Such findings lay a foundation for future work aimed at informing physiological models and intervention targets.

Evidence Base Update on the Assessment of Irritability, Anger, and Aggression in Youth.

OBJECTIVE: Irritability, anger, and aggression have garnered significant attention from youth mental health researchers and clinicians; however, fundamental challenges of conceptualization and measurement persist. This article reviews the evidence base for assessing these transdiagnostic constructs in children and adolescents. METHOD: We conducted a preregistered systematic review of the evidence behind instruments used to measure irritability, anger, aggression, and related problems in youth. Searches were conducted in PsycINFO and PubMed, identifying 4,664 unique articles. Eligibility criteria focused on self- and proxy-report measures with peer-reviewed psychometric evidence from studies in English with youths ages 3-18. Additional measures were found through ancillary search strategies (e.g. book chapters, review articles, test publishers). Measures were screened and coded by multiple raters with acceptable reliability. RESULTS: Overall, 68 instruments met criteria for inclusion, with scales covering irritability (n = 15), anger (n = 19), aggression (n = 45), and/or general overt externalizing problems (n = 27). Regarding overall psychometric support, 6 measures (8.8%) were classified as Excellent, 46 (67.6%) were Good, and 16 (23.5%) were Adequate. Descriptive information (e.g. informants, scales, availability, translations) and psychometric properties (e.g. reliability, validity, norms) are summarized. CONCLUSIONS: Numerous instruments for youth irritability, anger, and aggression exist with varying degrees of empirical support for specific applications. Although some measures were especially strong, none had uniformly excellent properties across all dimensions, signaling the need for further research in particular areas. Findings promote conceptual clarity while also producing a well-characterized toolkit for researchers and clinicians addressing transdiagnostic problems affecting youth.

Cannabinoid treatment for the symptoms of autism spectrum disorder.

INTRODUCTION: Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting approximately 3% of school-age children. The core symptoms are deficits in social communication and restricted and repetitive patterns of behavior. Associated problems in cognition, language, behavior, sleep and mood are prevalent. Currently, no established pharmacological treatment exists for core ASD symptoms. Risperidone and aripiprazole are used to manage associated irritability, but their effectiveness is limited and adverse events are common. AREAS COVERED: This mini-review summarizes existing scientific literature and ongoing clinical trials concerning cannabinoid treatment for ASD. Uncontrolled case series have documented improvements in both core ASD symptoms and related behavioral challenges in children treated with cannabis extracts rich in cannabidiol (CBD). Placebo-controlled studies involving CBD-rich cannabis extracts and/or pure CBD in children with ASD have demonstrated mixed efficacy results. A similar outcome was observed in a placebo-controlled study of pure CBD addressing social avoidance in Fragile X syndrome. Importantly, these studies have shown relatively high safety and tolerability. EXPERT OPINION: While current clinical data suggest the potential of CBD and CBD-rich cannabis extract in managing core and behavioral deficits in ASD, it is prudent to await the results of ongoing placebo-controlled trials before considering CBD treatment for ASD.

An expert opinion on the pharmacological interventions for Disruptive Mood Dysregulation Disorder (DMDD).

INTRODUCTION: Disruptive Mood Dysregulation Disorder (DMDD) was officially introduced as a new diagnostic entity in the Diagnostic and Statistical Manual of Mental Disorder, Fifth Edition (DSM-5), under the category of depressive disorders. AREAS COVERED: A comprehensive overview and a critical commentary on the currently investigated psychopharmacological approaches for the treatment of DMDD have been here provided. EXPERT OPINION: Behavioral and psychosocial interventions should be considered as first-line treatment strategies. When ineffective or partially effective, psychopharmacological strategy is recommended. Overall, pharmacological strategy should be preferred in those individuals with psychiatric comorbidities (e.g. ADHD). Indeed, so far published studies on pharmacological strategies in DMDD are scant and heterogeneous (i.e. age, assessment tools, symptomatology profile, comorbidity, and so forth). Therefore, DMDD psychopharmacological guidelines are needed, particularly to guide clinicians toward the patient's typical symptom profile who could benefit from psychopharmacological strategy.

Acceptance and Commitment Therapy for Anger, Irritability, and Aggression in Children, Adolescents, and Young Adults: A Systematic Review of Intervention Studies.

The onset of childhood disruptive behaviors is one of the most common presenting difficulties to clinics worldwide. Acceptance and commitment therapy (ACT) has shown to be effective in the reduction of anger and aggression among adults, however to date there has been no systematic review that has examined the effectiveness of ACT in addressing anger and aggression among children, adolescents, and young adults. The current systematic review aimed to evaluate the methodological standing and effectiveness of the peer-reviewed literature of ACT on anger and aggression for this population. PsycINFO, PubMed, and MEDLINE databases were searched systematically in June 2022 to identify studies in English published on the use of ACT for anger and aggression in children, adolescents, and young adults. Seven studies met the inclusion criteria with a combined sample of 305 participants across the interventions. The most common outcome measures used were self-report ratings of anger among participants. Studies were characterized by poor methodological rigor and findings were mixed as regards the effectiveness of ACT in addressing anger and aggression in this population. Some evidence suggests that group ACT may be effective in reducing self-report measures of anger, but no firm conclusions can be drawn from the extant literature due to the heterogeneous nature of the studies, and limited information about ACT protocols and treatment delivery. Further higher-powered studies comparing ACT to treatment as usual or waitlist are needed to clarify what ACT may add as a treatment to anger and aggression in this population.