Defining and measuring irritability: Construct clarification and differentiation

Dysphoria and Irritability-Diagnostic Pitfalls in the Assessment of Interictal Dysphoric Disorder in Epilepsy

This article aims to review the concept of epilepsy-specific psychiatric disturbance, Interictal Dysphoric Disorder (IDD), focusing on issues related to its core symptoms and methodological pitfalls. In the psychiatric literature, an epilepsy-specific pleomorphic mood disorder has been long recognized and described as IDD, a condition characterized by eight symptoms, which are grouped into four labile depressive symptoms, two labile affective symptoms, and two specific symptoms. The existence of IDD is still a matter of debate because of several methodological issues. The main features of IDD, such as dysphoria and irritability, lack precise and clear definition. This review article explores the different definitions and approaches towards both terms described in the psychiatric literature and the rationale for modifying the diagnostic process of IDD.

The association of phasic irritability (aggressive outbursts) and tonic irritability (irritable mood) to depression occurrences, symptoms, and subtypes

BACKGROUND

Research among adults has rarely differentiated between tonic irritability (i.e., irritable mood) and phasic irritability (i.e., aggressive outbursts) with respect to multiple dimensions of depression. The current study explored both tonic and phasic irritability in relation to depression severity, depression chronicity, age of depression onset, individual depressive symptom, and depression subtypes.

METHODS

The study included participants (N = 5692) from the National Comorbidity Survey - Replication (NCS-R) part two. The NCS-R used lay-administered, fully standardized diagnostic interviews. The current study implemented linear models, generalized linear models, Cox proportional hazard model, and latent class regression.

RESULTS

Both types of irritability were significantly associated with greater risk for MDD diagnosis, as well as risk for having at least one depressive symptom, early MDE onset, and MDE chronicity. Both phasic and tonic irritability were associated with greater odds of specific depressive symptoms and were differentially related to distinct depressive symptom constellations. Phasic irritability related only to severe depression. Lastly, both phasic and tonic irritability was associated with suicidal ideation, but only phasic irritability was associated with a suicide plan and attempt, above and beyond depression subtypes.

CONCLUSIONS

Both phasic and tonic irritability differentially related to almost all aspects of depression in adults. Specifically, tonic irritability showed overall stronger associations with various depressive features, whereas phasic irritability marked higher depressive severity.

Differential associations of phasic and tonic irritability to suicidality among U.S. adults

Research on the relations between irritability and suicidality among adults has rarely compared or differentiated between tonic versus phasic irritability. The current cross-sectional study investigated the role of both tonic and phasic irritability in relation to lifetime suicidal ideation, plans, and attempts. The study included adult participants who completed the suicidality module from the National Comorbidity Survey - Replication (NCS-R) (N = 7683 for suicidal ideation and N = 1223 for suicidal plan and attempt). The NCS-R used lay-administered, standardized diagnostic interviews. Phasic and tonic irritability were assessed with individual screener items from the World Health Organization Composite International Diagnostic Interviews (CIDI). The current study used logistic regression, weighted Cox proportional hazard model, and multinomial logit regression, adjusting for sex, race/ethnicity, age, education, and marital status. Both types of irritability were included simultaneously in the models. Results indicated that both types of irritability were significantly associated with increased odds of suicidal ideation (phasic: Odds Ratio 2.72 [2.35,3.14]); tonic: OR 2.34 [2.04,2.68]), age of first-time suicidal ideation (phasic: Adjusted Hazard Ratio 2.87 [2.27, 3.63]; tonic: AHR 2.12 [1.76,2.54]), and suicide attempt (phasic: OR 1.53 [1.13,2.07]); tonic: OR 1.44 [1.11,1.89]). Only tonic but not phasic irritability was associated with suicide plans (OR 1.39 [1.08,1.79]). When suicide attempts were divided into those that were impulsive versus planned and compared them to no suicide attempt, both types of irritability were associated planned attempts, (phasic: OR 1.53 [1.13,2.07]); tonic: OR 1.44 [1.11,1.89]) but only phasic irritability was related to impulsive attempts (OR 1.70 [1.10,2.64]). Phasic and tonic irritability show differential relations to and can serve as differential markers for suicide-related outcomes in adults.

The Impact of COVID-19 on Adolescents' Daily Lives: The Role of Parent-Child Relationship Quality

COVID-19 lockdown measures have profoundly impacted adolescent' daily life, with research suggesting an increase in irritability, stress, loneliness, and family conflict. A potential protective factor is parent-child relationship quality; however, no studies have investigated this. We used data from SIGMA, a longitudinal, experience sampling cohort study, in which N = 173 adolescents aged 11 to 20 were tested before and during COVID-19. Multilevel analyses showed decreased daily-life irritability and increased loneliness from pre- to mid-pandemic. Daily-life stress levels were unchanged. Relationship quality was negatively associated with irritability and loneliness and buffered against the increase in loneliness. Effect sizes were small and do not support a strong effect of the first lockdown on irritability, stress, loneliness, and family conflict in adolescents.

Mild Behavioral Impairment: A New At-Risk State for Alzheimer's Disease?

Improving our response to Alzheimer's disease (AD), including prevention and early intervention, is critical for maximizing healthy aging outcomes. Identifying older adults at highest risk for AD would provide an opportunity to offer support, plan for the future, and implement strategies to enhance cognitive and functional outcomes. The emergence of neuropsychiatric symptoms may be one indicator of early AD-related cognitive decline, but distinguishing symptoms from those due to other causes can be challenging. Mild behavioral impairment (MBI) describes an at-risk state for cognitive decline characterized by the late-life onset of neuropsychiatric symptoms. In this article, we discuss the current conceptualization of MBI, the potential for its characteristic neuropsychiatric symptoms to indicate risk for future cognitive decline, and present potential clinical implications. [Journal of Gerontological Nursing, 47(3), 29-36.].

Chronic Irritability in Youth: A Reprise on Challenges and Opportunities Toward Meeting Unmet Clinical Needs

This commentary focuses on irritability, one subtype of emotion dysregulation. We review literature demonstrating that irritability is not a developmental phenotype of bipolar disorder, but is longitudinally associated with unipolar depression and anxiety and genetically associated with unipolar depression, anxiety, and attention-deficit hyperactivity disorder. We describe how irritability is amenable to translational research, in part because of the relevance of frustrative nonreward, a model developed in rodents, to human irritability. Last, we demonstrate how such research has suggested a novel exposure-based intervention for irritability.

Irritability in Mood Disorders: Neurobiological Underpinnings and Implications for Pharmacological Intervention

Feeling irritable is a common experience, both in health and disease. In the context of psychiatric illnesses, it is a transdiagnostic phenomenon that features across all ages, and often causes significant distress and impairment. In mood disorders, irritability is near ubiquitous and plays a central role in diagnosis and yet, despite its prevalence, it remains poorly understood. A neurobiological model of irritability posits that, in children and adolescents, it is consequent upon deficits in reward and threat processing, involving regions such as the amygdala and frontal cortices. In comparison, in adults with mood disorders, the few studies that have been conducted implicate the amygdala, orbitofrontal cortices, and hypothalamus; however, the patterns of activity in these areas are at variance with the findings in youth. These age-related differences seem to extend to the neurochemistry of irritability, with links between increased monoamine transmission and irritability evident in adults, but aberrant levels of, and responses to, dopamine in youth. Presently, there are no specific treatments that have significant efficacy in reducing irritability in mood disorders. However, treatments that hold some potential and warrant further exploration include agents that act on serotonergic and dopaminergic systems, especially as irritability may serve as a prognostic indicator for overall clinical responsiveness to specific medications. Therefore, for understanding and treatment of irritability to advance meaningfully, it is imperative that an accurate definition and means of measuring irritability are developed. To achieve this, it is necessary that the subjective experience of irritability, both in health and illness, is better understood. These insights will inform an accurate, comprehensive, and valid interrogation of the qualities of irritability in health and illness, and allow not only a clinical appreciation of the phenomenon, but also a deeper understanding of its important role within the development and manifestation of mood disorders.

Observational measures of early irritability predict children's psychopathology risk

Irritability is a transdiagnostic feature of diverse forms of psychopathology and a rapidly growing literature implicates the construct in child maladaptation. However, most irritability measures currently used are drawn from parent-report questionnaires not designed to measure irritability per se; furthermore, parent report methods have several important limitations. We therefore examined the utility of observational ratings of children's irritability in predicting later psychopathology symptoms. Four-hundred and nine 3-year-old children (208 girls) completed observational tasks tapping temperamental emotionality and parents completed questionnaires assessing child irritability and anger. Parent-reported child psychopathology symptoms were assessed concurrently to the irritability assessment and when children were 5 and 8 years old. Children's irritability observed during tasks that did not typically elicit anger predicted their later depressive and hyperactivity symptoms, above and beyond parent-reported irritability and context-appropriate observed anger. Our findings support the use of observational indices of irritability and have implications for the development of observational paradigms designed to assess this construct in childhood.

The role of genetic and environmental factors in covariation between anxiety and anger in childhood

Higher levels of anger expression, as well as lower levels of anger control, have been reported for adults with anxiety disorders compared to individuals without anxiety disorders. Different to the research on adults, very few studies examined the relationship between anxiety and anger in childhood. In our study, we investigated 398 Italian twin pairs (74 MZ male, 70 MZ female, 134 same-sex dizygotic-53 male, 81 female-, and 120 unlike-sex dizygotic twin pairs), aged 8-17 (mean 13.06 ± 2.59): (i) the heritability of a childhood anger phenotype; (ii) the association between five anxiety domains and anger; (iii) the role of possible common etiological factors in explaining the observed comorbidity and overlap in the risk between anxiety phenotypes and anger. The study demonstrated that anger, assessed by CBCL items, is heritable in children at a similar rate to prior studies (40%). Our research found low to moderate rate of correlation between anger and anxiety (from 0.10 to 0.19). Finally, the present study found that the majority of etiological influences on anxiety and anger are independent of each other. Data showed that shared environmental influences have some small effects on the phenotypic covariation between the anxiety phenotypes and anger (12%); whereas unique environmental influences have an almost negligible effect (1%). Our analyses did not reveal the effect of genetic effects in explaining the covariation between these phenotypes.

Predictors of irritability symptoms in mildly depressed perimenopausal women

OBJECTIVE

Irritability is a highly burdensome complaint, commonly, but not universally, linked with depressive symptoms. While increased variability in estradiol has been associated with depressive symptoms during perimenopause, more insight is needed into reproductive hormone dynamics and other factors that predispose perimenopausal women to irritable mood.

METHODS

Among 50 mildly depressed perimenopausal women (mean (SD) age 48.4 (3.9) years), severity of irritability symptoms (on Symptom Questionnaire Hostility subscale, range 0-23) was assessed weekly for eight weeks, concurrent with potential predictors. Associations between these were examined using generalized estimating equating models.

RESULTS

Most women (82.0%) reported having moderate to severe irritability at least once. However, the severity of irritability was highly variable from week-to-week (between-subject mean coefficient of variation [CV] 72.9% and within-subject mean CV 63.7%). In multivariate analyses, less variable serum estradiol levels (standardized β within-person CV -0.23 95%CI [-0.32, -0.14], p < 0.001), greater depression severity (0.45 [0.35, 0.56], p < 0.001), younger age (-0.23, [-0.28, -0.09], p < 0.001), and more frequent vasomotor symptoms (0.14 [0.05, 0.23], p = 0.002) were associated with more irritability. Depression severity explained the largest portion of the variance in irritability, but still not more than 20.3%. Neither crude values, weekly change in, or variability of progesterone or FSH levels were associated with irritability.

CONCLUSIONS

Irritability was highly prevalent among mildly depressed perimenopausal women. In contrast to depressive symptoms, decreased rather than increased variability in estradiol levels was associated with more irritability. This highlights that irritable mood can be disentangled from depressive symptoms in perimenopausal women and might be linked with different estradiol dynamics.

The impact of transcranial magnetic stimulation (TMS) on irritability occurring with acute major depressive disorder (MDD)

OBJECTIVE

To examine the impact (if any) of a course of transcranial magnetic stimulation (TMS) on irritability occurring in association with acute major depressive disorder (MDD).

METHOD

In a naturalistic study, patients with MDD according to DSM-5 criteria were given 20 daily TMS treatments. A visual analogue scale for irritability (VAS-I) was developed. Objective tools included the six-item Hamilton Depression Rating Scale (HAMDS6) and the Clinical Global Impression - Severity (CGI-S).

RESULTS

Fifty patients received 53 courses. Forty-seven courses achieved remission on both HAMD6 and CGI-S and six courses did not achieve remission with either. Irritability significantly reduced when MDD remission was achieved but was unchanged when remission was not achieved.

CONCLUSION

TMS reduces irritability occurring in association with MDD when this treatment affects MDD remission, but not when remission is not affected.

The impact of 'cluster maintenance TMS' on irritability occurring in major depressive disorder

OBJECTIVE

To determine the impact of clustered maintenance transcranial magnetic stimulation (TMS) on irritability occurring in treatment-resistant major depressive disorder (MDD).

METHOD

A naturalistic study of 106 courses that includes pre- and posttreatment assessments of subjective and objective depression and a subjective measure of irritability developed for this study.

RESULTS

Forty-six participants (35 females), mean age 43.2 years (14.3), completed 106 courses. There was a significant reduction in irritability and depression scores (p < .001). The change in irritability scores was significantly correlated with the change in depression scores, r = .40, p < .001.

CONCLUSION

TMS has the capacity to reduce the irritability co-occurring with treatment-resistant MDD, known to be responsive to TMS. This increases the possibility of using TMS in the treatment of irritability co-occurring with other disorders or standing alone (should irritability be categorized as a stand-alone disorder).

Sleepy Psychotherapists: How Clinicians' Biological Factors May Affect the Conduct of Psychotherapy

OBJECTIVE

Numerous therapist variables and cognitive biases can affect the quality of the therapeutic alliance and the conduct and outcomes of psychotherapy. This article aims to examine factors that potentially affect clinician performance, including chronobiological variables of clinicians and patients.

METHODS

The author reviewed literature pertaining to biological influences on human cognitive performance and considered how these factors may apply to the practice of psychotherapy.

RESULTS

Biological factors potentially affecting the conduct and quality of psychotherapy were identified. These factors include decision fatigue, hunger, sleep deficit, shift work, and several chronobiological issues related to circadian rhythms and episodic ultradian rhythms. In addition, misaligned scheduling of psychotherapy sessions in relation to therapist and patient evening-morning chronotypes may impede the effectiveness of psychotherapy.

CONCLUSIONS

The practice of psychotherapy is cognitively demanding, requiring that clinicians remain constantly alert and in command of their executive functions. Decreases in clinician alertness resulting from homeostatic depletion, chronobiologically misaligned schedules, and illness-associated factors may reduce the quality and benefit of psychotherapy sessions. Mitigation strategies are available. Investigations of these factors are needed.

Irritability and mood symptoms in adolescent girls: Trait anxiety and emotion dysregulation as mediators

BACKGROUND

Irritability is a common symptom in youth that is thought to be predictive of mood disorders. Its effects on mood are likely to be age-dependent, with direct and indirect mediators. We assessed age-related effects and mediators of irritability in adolescent girls with subthreshold depressive and manic symptoms.

METHODS

We analysed the irritability item from the Mood Disorder Questionnaire in 3 cohorts of girls aged 12-18years (N=229); 12-13years (N=82); 14-15years (N=68); and 16-18years (N=79). They also completed mood, anxiety and emotion regulation questionnaires. MANOVA, correlations and bootstrapped mediation analyses were performed with SPSS®v25 and Hayes Processv3.5®.

RESULTS

Overall, irritable girls had higher depressive and manic symptoms, trait anxiety and emotion dysregulation than those who were not irritable. Significantly higher rates of irritability were observed in mid-adolescents (aged 14-15years; p = 0.001). Notably, irritability exerted effects on depressive symptoms via trait anxiety, non-acceptance of emotions and dysregulation in emotion clarity throughout adolescence. However, irritability directly exerted effects on manic symptoms in mid-adolescence but in older adolescents, their relationship was indirect via impulse control dysregulation.

LIMITATIONS

The cross-sectional design and non-clinical sample limit generalisability of our findings.

CONCLUSIONS

Irritability is involved in subthreshold depressive symptoms, via trait anxiety and perceptual emotion dysregulation. On the other hand, irritability is directly and indirectly associated with subthreshold manic symptoms via dysregulated impulse control depending on age. Therefore, screening for irritability, trait anxiety and emotion dysregulation throughout adolescence may facilitate the early detection of subthreshold depressive and manic symptoms, and the implementation of preventive strategies.

Aggressive outbursts among adults with major depressive disorder: Results from the Collaborative Psychiatric Epidemiological Surveys

INTRODUCTION

Little is known about the epidemiology of aggressive outbursts, including physical assault, property destruction, and verbal aggression, among adults with unipolar Major Depressive Disorder (MDD).

METHODS

We examined the prevalence and correlates of aggressive outbursts among adults with primary MDD (N = 2539) from the Collaborative Psychiatric Epidemiological Surveys (N = 20,013) using generalized linear models.

RESULTS

The prevalence estimate of any aggressive outbursts was 58.7% among adults with MDD. MDD was associated with aggressive outbursts independent of other psychiatric diagnoses. The prevalence of aggressive outbursts differed significantly by age, race/ethnicity, sex, education, marital status, and employment status, and psychiatric diagnoses. Aggressive outbursts were associated with greater severity and earlier age of onset for MDD. Positive associations were also found between the frequency of aggressive outbursts and depressive symptoms including weight/appetite change, fatigue, recurrent thoughts of death. Moreover, aggressive outbursts significantly multiplied the odds of experiencing more severe functional impairment, suicidal ideation, suicide plan, and suicide attempt.

CONCLUSION

Aggressive outbursts are much more common than previously recognized among adults with MDD. The significant association of aggressive outbursts with MDD characteristics, increased functional impairment, and suicidal thoughts and behaviors make them an important target for assessment and treatment for adults with MDD.

Efficacy of Yokukansan, a traditional Japanese herbal medicine, in patients with dizziness and irritability

OBJECTIVE

Irritability is an emotional stress symptom that causes or exacerbates dizziness. Antidepressants may be helpful for some conditions that are accompanied by irritability; however, they do not completely inhibit irritability. Yokukansan (YKS), a traditional Japanese herbal medicine, has been used for neurosis, insomnia, and children's irritability and night crying. The study investigated the efficacy of YKS in nystagmus in patients with chronic dizziness and irritability.

METHODS

Twenty-two cases with chronic dizziness and irritability were reviewed retrospectively. The patients were divided into two groups: control patients (0-7 days of treatment) and YKS-treated patients (YKS cases; >7 days of treatment). Dizziness before and during (after, in the controls) YKS treatment was evaluated by scoring the nystagmus intensity on a 5-point scale. The average scores were calculated within a maximum of 6 months before and during or after treatment. The normalized scores were also calculated. The optimal treatment regimen was calculated via receiver operating characteristic (ROC) curve analysis.

RESULTS

There were six control cases (1 male, 5 females; mean age: 59.5 years). There were 16 YKS cases (3 males, 13 females; mean age: 61.8 years). While the group mean nystagmus intensity scores significantly decreased from 1.18 to 0.73 in the YKS cases, it did not change in the control cases. The group mean of the normalized nystagmus intensity scores during treatment was 0.73 in the YKS cases. The results of the ROC curve analysis indicated the optimal cut-off period of the YKS treatment was 10 days.

CONCLUSION

The oral administration of YKS for more than 10 days was optimal. The treatments with YKS could be a good option for the treatments of vertigo.

Irritability through Research Domain Criteria: an opportunity for transdiagnostic conceptualisation

Irritability is a transdiagnostic phenomenon that, despite its ubiquity and significant impact, is poorly conceptualised, defined and measured. As it lacks specificity, efforts to examine irritability in adults by using a diagnostic category perspective have been hamstrung. Therefore, using a Research Domain Criteria (RDoC) approach to examine irritability in adults, which spans many constructs and domains, may have a better chance of yielding underlying mechanisms that can then be mapped onto various diagnostic categories. Recently, a model has been proposed for irritability in children and adolescents that uses the RDoC framework; however, this model, which accounts for chronic, persistent irritability, may not necessarily transpose to adults. Therefore, use of the RDoC framework to examine irritability in adults is urgently needed, as it may shed light on this currently amorphous phenomenon and the many disorders within which it operates.

Self-perceived irritability among OEF/OIF/OND veterans with a history of deployment-related mTBI: Associations with prospective memory and quality of life

OBJECTIVE

Examine relationships between self-perceived irritability, prospective memory, and quality of life (QOL) following mild traumatic brain injury (mTBI). Methods: 75 OEF/OIF/OND-era Veterans (56 deployment-related mTBI; 19 no history of TBI), were administered a battery of neuropsychological tests and self-report measures of mood and QOL. Self-perceived irritability was measured using the Neurobehavioral Symptom Inventory. Prospective memory (PM) was measured using the Memory for Intentions Test (MIST). Results: Self-perceived irritability was significantly higher for Veterans with, versus without, a history of deployment-related mTBI. Among Veterans with a history of mTBI, self-perceived irritability was inversely associated with PM performance, even after adjusting for PTSD severity. Greater self-perceived irritability was also associated with higher depressive symptoms and reduced QOL for perceived physical health, psychological health, social support, and environmental factors; however, only social support remained significant after adjusting for PTSD severity. Depression symptom severity was not significantly associated with PM, suggesting that PM may be uniquely related to self-perceived irritability rather than mood dysregulation more generally. Conclusions: Findings provide preliminary evidence of a relationship between PM and self-perceived irritability in Veterans with a history of mTBI. PM and irritability may be related via their mutual reliance on high-level cognitive control. Results illustrate possible cognitive and affective factors contributing to psychological and interpersonal challenges for this population. Future investigations with larger and more diverse samples are needed to replicate findings and explore potential mechanisms linking irritability and PM following mTBI.

Joining the pieces in childhood irritability: Distinct typologies predict conduct, depressive, and anxiety symptoms

This study utilised a person-centered approach to understand childhood irritability as a transdiagnostic feature of psychopathology. Latent profile analysis was employed within a community sample (n = 93) of 9-11 year olds to identify typologies of self-regulation capabilities, positive wellbeing characteristics of hope and flourishing, and social functioning that cluster with children's irritability to mitigate risk for psychopathology symptoms. Three distinct profiles of youth were derived, High Irritability/Low Self-Regulation of Negative Emotion (9%), Moderate Irritability/Low Behavioural Control (34%) and Low Irritability/High Positive Wellbeing Characteristics (57%). Profiles were empirically validated and differentially related to symptoms of anxiety, depression and conduct problems. Notably, High Irritability/Low Self-Regulation of Negative Emotion children were characterised by the highest levels of irritability and peer problems and the lowest self-regulation of negative emotion, prosocial behaviours, hope and flourishing relative to children within the other profiles, pointing to the potential utility of future targeted, transdiagnostic interventions. Within our community-based sample, a protective profile of Low Irritability/High Positive Wellbeing Characteristics children were also described by the lowest levels of irritability and peer problems and the highest positive and negative emotion self-regulation, behavioural control, prosocial behaviours, hope and flourishing. Findings demonstrate that different levels of irritability severity cluster with different self-regulation capabilities and wellbeing characteristics and predict risk for different types of psychopathology. Targeted interventions should seek to address children's irritability alongside self-regulation and positive wellbeing characteristics to further mitigate risks of psychopathology and associated problems.

Hostility in cancer patients as an underexplored facet of distress

OBJECTIVE

In the present study, we aimed to assess hostility and to examine its association with formal psychiatric diagnosis, coping, cancer worries, and quality of life in cancer patients.

METHODS

The World Health Organization (WHO) Composite International Diagnostic Interview (CIDI) to make an ICD-10 (International Classification of Disease) psychiatric diagnosis was applied to 516 cancer outpatients. The patients also completed the Brief Symptom Inventory-53 to assess hostility (BSI-HOS), and the Mini-Mental Adjustment to cancer scale (Mini-MAC). A subset of patients completed the Cancer Worries Inventory (CWI), the Openness Scale, and the Quality of Life Index.

RESULTS

By analyzing the distribution of the responses 25% of the patients had moderate and 11% high levels of hostility, with about 20% being BSI-HOS "cases." Hostility was higher in patients with a formal ICD-10 psychiatric diagnosis (mainly major depression, other depressive disorders, anxiety disorders) than patients without ICD-10 diagnosis. However, about 25% of ICD-10-non cases also had moderate-to-high hostility levels. Hostility was associated with Mini-MAC hopelessness and anxious preoccupation, poorer quality of life, worries (mainly problems sin interpersonal relationships), and inability to openly discuss these problems within the family.

CONCLUSIONS

Hostility and its components should be considered as dimensions to be more carefully explored in screening for distress in cancer clinical settings for its implications in negatively impacting on quality of life, coping and relationships with the family, and possibly the health care system.

Association between irritability and suicidal ideation in three clinical trials of adults with major depressive disorder

Irritability in pediatric samples is associated with higher rates of subsequent suicide-related outcomes. No study, to date, has evaluated the longitudinal association between irritability and suicidal ideation (SI) in adults with major depressive disorder (MDD). This report evaluated whether irritability is associated with SI at the same visit (i.e., concurrently) and whether early changes in irritability with antidepressant treatment predict subsequent levels of SI. Participants of Combining Medications to Enhance Depression Outcomes (CO-MED, n = 665), Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care (EMBARC, n = 296), and Suicide Assessment Methodology Study (SAMS, n = 266) were included. Repeated-measures mixed model analyses evaluated concurrent association throughout the trial between irritability (five-item irritability domain of Concise Associated Symptom Tracking scale) and SI (three-item suicidal thoughts factor of Concise Health Risk Tracking scale) after controlling for overall depression (excluding suicidality-related item), and predicted subsequent levels of SI (repeated observations from week-2-to-week-8) based on early (baseline-to-week-2) changes in irritability after controlling for early changes in overall depression. Higher irritability was associated with higher SI concurrently; estimates (standard error) were 0.18 (0.02, p < 0.0001), 0.64 (0.02, p < 0.0001), and 0.26 (0.04, p < 0.0001) in CO-MED, EMBARC, and SAMS respectively. Greater baseline-to-week-2 reductions in irritability predicted lower levels of subsequent SI; estimates (standard errors) were -0.08 (0.03, p = 0.023), -0.50 (0.05, p < 0.0001), and -0.12 (0.05, p = 0.024) in CO-MED, EMBARC, and SAMS, respectively. Controlling for anxiety or insomnia produced similar results. In conclusion, irritability and SI were consistently linked in adults with MDD. These findings support careful assessment of irritability in suicide risk assessment.

Moving the dial on prenatal stress mechanisms of neurodevelopmental vulnerability to mental health problems: A personalized prevention proof of concept

Prenatal stress exposure increases vulnerability to virtually all forms of psychopathology. Based on this robust evidence base, we propose a "Mental Health, Earlier" paradigm shift for prenatal stress research, which moves from the documentation of stress-related outcomes to their prevention, with a focus on infant neurodevelopmental indicators of vulnerability to subsequent mental health problems. Achieving this requires an expansive team science approach. As an exemplar, we introduce the Promoting Healthy Brain Project (PHBP), a randomized trial testing the impact of the Wellness-4-2 personalized prenatal stress-reduction intervention on stress-related alterations in infant neurodevelopmental trajectories in the first year of life. Wellness-4-2 utilizes bio-integrated stress monitoring for just-in-time adaptive intervention. We highlight unique challenges and opportunities this novel team science approach presents in synergizing expertise across predictive analytics, bioengineering, health information technology, prevention science, maternal-fetal medicine, neonatology, pediatrics, and neurodevelopmental science. We discuss how innovations across many areas of study facilitate this personalized preventive approach, using developmentally sensitive brain and behavioral methods to investigate whether altering children's adverse gestational exposures, i.e., maternal stress in the womb, can improve their mental health outlooks. In so doing, we seek to propel developmental SEED research towards preventive applications with the potential to reduce the pernicious effect of prenatal stress on neurodevelopment, mental health, and wellbeing.

Irritability Disorders in Adults: Diagnostic Categories Missing in Plain Sight?

Research into irritability has focused largely on its developmental and child-adolescent manifestations. Although irritability appears to be as elemental an experience as anxiety or depression, diagnoses highlighting irritability as the focal ingredient have yet to be delineated for adults. Instead, irritability-related diagnoses in adults have largely emphasized externalizing behaviors, depressed mood, and personality. Consequently, patients complaining of irritability are sometimes shoehorned into diagnostic categories that they do not experience as authentic representations of their lived experiences. This article proposes that the symptom of irritability might be productively reenvisioned as a focal point, analogous to anxiety and depression, around which irritability-related syndromes and disorders in adults might coalesce. If anxiety, depressive, insomnia, and pain disorders, why not irritability disorders? Both state and trait characteristics of irritability can lend themselves to DSM diagnostic frames. Based on clinical observations, specific irritability disorders in adults can be envisioned, modeled as Irritability Disorder of Adulthood, Irritability Disorder Secondary to Another Medical Condition, Substance-Induced Irritability Disorder, Adjustment Disorder With Irritable Mood, and the like. Further delineation of irritability phenomena, syndromes, and possible disorders in adults is warranted to advance investigation, guide assessment, and improve treatment.

Comorbid anxiety and irritability symptoms and their association with cognitive functioning in children with ADHD

Anxiety and irritability symptoms frequently co-occur in children with Attention-Deficit/Hyperactivity Disorder (ADHD). This study aims to investigate whether irritability and anxiety are uniquely associated with performance on measures of cognitive functioning in children with ADHD and whether these associations hold when accounting for confounding variables. Baseline data was used from a randomised controlled trial of cognitive behavioural therapy for anxiety in children with ADHD (N = 219, 8-13 years). Anxiety was assessed using the child- and parent-reported Spence Children's Anxiety Scale, while irritability was assessed using the parent-reported Affective Reactivity Index. Children completed the National Institutes of Health Toolbox - Cognition Battery. Higher symptoms of anxiety were uniquely associated with performance on the Dimensional Card Change Sort Test (β = -2.75, confidence interval (CI) [-4.97, -.52], p = .02) and the List Sort Working Memory Test (β = -2.57, CI [-4.43, -.70], p = .01), while higher symptoms of irritability were negatively associated with Picture Vocabulary Test (β = -2.00, CI [-3.83, -.16], p = .03). These associations did not survive correction for multiple comparisons. There was little evidence of an association between anxiety or irritability symptoms and cognitive functioning. Frequent co-occurrence of anxiety and irritability suggests clinicians working with children with ADHD should assess co-morbid symptom profiles to inform the provision of optimum care.

Examining the predictive association of irritability with borderline personality disorder in a clinical sample of female adolescents

OBJECTIVES

Borderline personality disorder (BPD) is a disorder associated with emotion dysregulation and is common in clinical samples of adolescents. The identification and delineation of BPD from other disorders is important, yet methods for effectively screening for BPD are lacking. Here, we examine whether irritability can be used as a screening item for BPD in adolescents at risk for the disorder.

METHODS

We assessed Diagnostic Interview for Borderline-Revised and Development of Well-Being Assessment scores in a clinical sample of female adolescents ages 12-17 (n = 78) to identify BPD and group cases into 'irritable' and 'non-irritable' mood types, respectively. We then examined the prevalence of irritability and its predictive association with BPD.

RESULTS

The prevalence of BPD was 26% (n = 20). There was a significant association between irritable mood and BPD, specifically (χ² (1) = 17.740, p < 0.001). Irritability was endorsed in all (n = 20) BPD cases (sensitivity: 100%), while in non-BPD cases (n = 58), irritability was endorsed in 27 (specificity: 53%; positive predictive value: 0.33; and negative predictive value: 1.0).

CONCLUSION

Irritability is a highly sensitive screening item for BPD in adolescents. The absence of irritability in an adolescent may be an important clinical tool to rule out BPD. © 2020 John Wiley & Sons, Ltd.

Exposure-Based Cognitive-Behavioral Therapy for Disruptive Mood Dysregulation Disorder: An Evidence-Based Case Study

Severe, chronic irritability is one of the most frequently reported problems in youth referred for psychiatric care. Irritability predicts adult depressive and anxiety disorders, and long-term impairment. Reflecting this pressing public health need, severe, chronic, and impairing irritability is now codified by the DSM-5 diagnosis of disruptive mood dysregulation disorder (DMDD). Since DMDD has only recently been added as its own nosological class, efficacious treatments that specifically target severe irritability as it presents in DMDD are still being developed. In a recent pilot study, we described the general concept of exposure-based cognitive-behavioral therapy (CBT) for irritability. This mechanism-driven treatment is based on our pathophysiological model of irritability that postulates two underlying mechanisms, which potentiate each other: (1) heightened reactivity to frustrative nonreward, and (2) aberrant approach responses to threat. In this case report, we describe and illustrate the specific therapeutic techniques used to address severe irritability in an 11-year-old boy with a primary diagnosis of DMDD. Specific techniques within this CBT include motivational interviewing to build commitment and target oppositionality; creation of an anger hierarchy; in-session controlled, gradual exposure; and parent training focusing on contingency management to counteract the instrumental learning deficits in irritable youth. Parents learn to tolerate their own emotional responses to their youth's irritability (e.g., parents engage in their own exposure) and increase their adaptive contingencies for their youth's behavior (e.g., withdraw attention during unwanted behavior, praise desirable behavior). Future directions in the context of this CBT, such as leveraging technology, computational modeling, and pathophysiological targets, are discussed.

Exploring Longitudinal Mechanisms of Irritability in Children: Implications for Cognitive-Behavioral Intervention

Severe irritability is a common and clinically important problem longitudinally associated with internalizing and externalizing problems in children. To better understand these mechanisms and to inform treatment research, we tested cognitive-behavioral processes as candidate mediators in the paths from irritability to later problems. Methods: A school sample (N = 238, 48% female, ages 8-10) was assessed at ~6-month intervals in fall (T1) and spring (T2) of third to fourth grade, and again the following fall (T3). Measures assessed irritability (T1/predictor); anger and sadness coping, intolerance of uncertainty, and rumination; (T1-T2/mediators); and anxiety, depressive symptoms, reactive aggression, and oppositionality (T1-T3/outcomes). Focused cross-lagged panel models, controlling for gender and grade, were specified to examine full (X_T1 ➔ M_T2 ➔ Y_T3) and half (X_T1 ➔ M_T2; M_T1 ➔ Y_T2) longitudinal mediation. Across one or more intervals, irritability predicted higher depressive symptoms, anxiety, reactive aggression, oppositionality, intolerance of uncertainty, and poor emotion coping. From T1 irritability to T2/T3 outcomes, mediation was found for poor sadness coping leading to reactive aggression and oppositionality; poor anger coping to anxiety, depressive symptoms, and oppositionality; and intolerance of uncertainty to anxiety. Results offer further evidence for internalizing and externalizing outcomes of youth irritability and new evidence suggesting underlying mechanisms. Irritability may confer risk for externalizing problems via poor sadness/anger coping, and for internalizing problems via poor anger coping and intolerance of uncertainty. Theoretical models and psychosocial treatment should consider addressing regulation of various unpleasant emotions as well as psychological flexibility and tolerating uncertainty.

The Internal Structure of the Aberrant Behavior Checklist Irritability Subscale: Implications for Studies of Irritability in Treatment-Seeking Youth With Autism Spectrum Disorders

Given the prominence of the Aberrant Behavior Checklist (ABC), Irritability Subscale (ABC-I), in treatment outcome studies, we conducted a critical examination of its internal consistency and relationship to other measures of irritability in 758 psychiatrically hospitalized youth with autism spectrum disorder. In exploratory and confirmation samples, we conducted factor and bifactor analyses to describe the internal structure of the ABC-I. Our results suggest that the ABC-I roughly represents a unidimensional construct of irritability, as indicated by a general factor in bifactor analysis. In addition to irritability, subordinate factors are presented that represent tantrums, verbal outbursts, self-harm, and negative affect. Notably, self-harm items explain a large proportion of variance independent of irritability. Therefore, their contribution in analyses of treatment effects should be considered. Further study or revision of the ABC-I may improve convergent validity with transdiagnostic formulations of irritability as well as prevent confound from self-harm in treatment studies for irritability in ASD.

Irritability characteristics and parameters in an international sample

BACKGROUND

Irritability is a symptom of fifteen psychiatric disorders and is widely known to scholars and the public. However, little is known about irritability as an individual construct. The purpose of the current study is to identify conceptualizations of specific characteristics of irritability.

METHODS

In this study, 402 participants from 10 countries answered nine qualitative questions about their personal causes, experience, and consequences of irritability as well as how they perceived the relationship between irritability and anger. They also answered three quantitative questions about the frequency, intensity, and duration of their irritability.

RESULTS

Results indicated that 99.3% of participants reported a lifetime incidence of irritability. On average, participants reported feeling irritable approximately one to two times per week for 30 min with an intensity that was somewhat bothersome. Women reported feeling irritable for a longer duration than men, and residents of China, Singapore, and the USA generally reported having a longer duration than residents of Ireland and the UK. Some themes that appeared unique to irritability were the physiological/biological/internal aspects of irritability and treatments that address emotional and physiological coping such as relaxation and recreation.

LIMITATIONS

Many participants equated irritability with anger, and generalizations by countries should be interpreted with caution due to a small sample within each country.

CONCLUSIONS

These findings support the conceptualization of irritability as a universal construct. It is recommended that future research continue to explore irritability to better help understand it as an independent construct in the context of diagnosis, assessment, research, and treatment.

How the Affective Reactivity Index (ARI) works for teachers as informants

BACKGROUND

The Affective Reactivity Index (ARI) is a brief instrument originally designed as a self- and parent report. However, the view of teachers, who can observe social situations that may give rise to irritability, is relevant. The goal is to provide the measurement qualities of the ARI score as reported by teachers.

METHOD

Children formed part of a longitudinal study on behavior problems in Barcelona (Spain) and they were assessed when they were 7 (N = 471) and 11 years old (N = 454) with questionnaires about psychopathology, anger and aggressive behavior, and a diagnostic interview answered by the parents, youths and teachers. Confirmatory factor analysis, measurement invariance, reliability and validity were studied for the ARI answered by teachers.

RESULTS

The 6-item, 1-factor model fitted well. Almost full metric invariance and partial scalar invariance was obtained across sex and over age. The ARI scores largely converged with other teacher-reported measures of anger and irritability, and with other measures of psychopathology, aggressive behavior, and callous-unemotional traits at a medium level. The associations with parent's measures were medium to low, and very low for child self-reported measures. The ARI scores significantly differentiated children with and without psychopathology and functional impairment, both cross-sectionally and longitudinally.

LIMITATIONS

Only one child self-report measure of irritability included. Limited internal consistency of some scale scores. Findings are mostly generalizable to Spanish children.

CONCLUSIONS

ARI could be a suitable instrument for measuring irritability as reported by teachers. The teacher's view can be useful when planning treatment by helping to identify treatment targets.

Measuring anger in patients experiencing chronic pain - A systematic review

Anger is prevalent in chronic pain and has been associated with pain perception, disability, behavior and treatment outcome. Objectives were (1) to survey in the context of chronic pain the application (and omission) of validated anger self-report instruments, (2) to discuss the instruments found in the context of emotion theories and (3) to identify a possible instrument preference. A systematic search of textbooks and review articles was first performed on validated instruments designed to measure the cognitive, the motivational and the subjective feeling component of anger. Thereafter, a systematic review aimed at finding chronic pain studies from 2005 to 2019 reporting on these instruments. Textbooks and reviews listed 16 validated self-report anger measurement instruments. 28 papers applying four of these were identified and two new instruments were additionally detected. The State-Trait Anger Expression (STAXI) and its precursors were most commonly used. Studies on chronic low back pain patients prevailed. In conclusion, anger in chronic pain patients is reliably measurable at low cost with self-report tools. The STAXI-II qualifies best for this purpose based on its extensive validation history. The majority of instruments lack sufficient theoretical and psychometric adequacy. A more detailed exploration of the cognitive anger component in chronic pain patients in future research is recommended.

Getting irritable about irritability?

Despite irritability being considered a symptom of several psychiatric disorders, there is no standardised definition or measurement of the construct within psychiatry. This lack of definition is in part due to a fundamental lack of understanding of what it means to be irritable and the foundational mechanisms that lead to its manifestation. This then poses a cyclical problem, whereby because the concept of irritability is poorly defined and is defined variably in different contexts, research utilising these various definitions and measures is inherently inconsistent. Hence, a new approach to studying irritability is required, one that examines the construct as being a product of tensions that arise because of discrepancies between expectations and reality. This new bottom-up definition of irritability does not rely on phenomenology alone, and therefore can be neurocognitively mapped and tested experimentally with greater precision. By establishing more sophisticated terminology and progressing to a standardised definition, the examination of irritability can progress in a meaningful way. However, this progress cannot be achieved without collaboration and multifaceted efforts from all schools of thought. Therefore, by getting irritable about irritability ourselves, we hope that a more constructive dialogue concerning this pervasive and important concept can be instigated, involving researchers from all schools of thought.

Relating irritability and suicidal ideation using mood and anxiety

BACKGROUND

Suicide is common in the context of depression and bipolar disorders, but there remains a lack of understanding as to how suicide ideation, a common symptom of mood disorders, progresses to suicidal behaviour. Irritability, a feature of some types of depression, is thought to contribute to the development of suicidal behaviour, but these associations are not well established.

OBJECTIVE

To examine the relationship between irritability and suicide ideation according to the subtype of depression expressed in patients with mood disorder.

METHODS

75 patients with mood disorders seen at the CADE (Clinical Assessment Diagnostic Evaluation) Clinic underwent clinical assessment for suicidal ideation (Paykel Suicide Scale), symptom severity (Young Mania Rating Scale (YMRS), Hamilton Rating Scale for Depression (HAM-D) (anxious depression), Montgomery-Åsberg Depression Rating Scale (MADRS) (melancholic depression)) and irritability (item 5 of the YMRS).

FINDINGS

Interestingly, irritability correlated with mania (r=0.734, p<0.001 (YMRS)) and depressive symptom scores (r=0.369, p<0.001 (MADRS); r=0.477, p<0.001 (HAM-D)), which in turn correlated with suicide ideation scores (r=0.364, p<0.01 (MADRS); r=0.275, p=0.017 (HAM-D)). However, despite this indirect association, there was no direct correlation between irritability and suicide ideation (r=0.050, p>0.05).

CONCLUSIONS

The nature of the relationship between irritability and suicidal ideation is determined by the emotional context within which irritability operates.

CLINICAL IMPLICATIONS

Findings suggest that rather than examining irritability alone, consideration of the subtype of depression, especially that of anxious depression, should be paramount in assessing suicide risk.

Exposure therapy for pediatric irritability: Theory and potential mechanisms

Pediatric irritability is prevalent and impairing, yet little is known about its pathophysiology and treatment. In this article, we build on our and others' previous work to posit core mechanisms of irritability operating across the brain, behavior, and environment. Specifically, we propose proximal processes that surround the symptomatology of irritability and are potential targets for an exposure-based cognitive-behavioral therapy (CBT) for irritability that our group has developed. The heart of this model focuses on neurocognitive processes: youth's encoding of nonreward and threat stimuli, which involves prediction error signaling in the brain, and cognitive control in the context of frustration. Alterations in these processes are theorized to be central to chronic, severe irritability. Environmental responses to youth's symptom expression are also examined. Exposure-based CBT for irritability utilizes controlled, in vivo exposure to nonreward and threat stimuli with the aim to engage cognitive control and target top-down regulation of frustration. This intervention integrates selected parent management training techniques to target symptom reinforcement processes. Continued pathophysiological and treatment studies of irritability will not only refine our emerging understanding of the phenotype, but also inform broader questions on the brain and behavioral mechanisms of CBT efficacy.

Interictal dysphoric disorder of epilepsy: A continuing diagnostic challenge

OBJECTIVE

The interictal dysphoric disorder (IDD) is a proposed epilepsy-specific mood disorder characterized by a cluster of symptoms such as depressed mood, irritability, euphoria, and anxiety. Since its introduction, the concept of IDD has been a matter of debate. This study aimed to evaluate the frequency of the IDD and the association between psychiatric disorders and IDD. We also analyzed potential associations between IDD symptoms and epilepsy-related variables.

METHODS

A consecutive group of 118 outpatients with epilepsy were screened. Ninety-six patients met inclusion criteria and examined by a trained psychiatrist using Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders fourth edition Text Revision (DSM-IV-TR) (SCID-I). In order to diagnose IDD, all participants completed the self-rating questionnaire consisting of a set of questions aimed to assess the eight key symptoms of IDD. On completion of the questionnaire, the psychiatrist reviewed all the data for completeness and accuracy with the patient.

RESULTS

In our group with epilepsy, we observed IDD in 49.0% (47 of 96) of people with epilepsy (PWE) with substantial overlap (85%) of IDD with depressive and anxiety disorders. The frequency of depressive mood, anergia, and irritability was significantly higher in patients with IDD diagnosis. Older age at epilepsy onset was associated with IDD.

STUDY LIMITATIONS

The cross-sectional study design, a consecutive sample of patients presenting to a tertiary referral center, a small sample size of the population, and applied methodology could have affected the results.

CONCLUSIONS

The present study indicates that IDD occurs in high frequency in PWE with a substantial overlap of IDD with depressive and anxiety disorders. The study highlights the importance of the observer-based systematic approach for diagnosing IDD and the usage of operationalized diagnostic criteria for psychiatric comorbidities in PWE. Future research should be directed at validating whether IDD is nosologically independent of other psychiatric conditions.

Suicidal behaviors and irritability in children and adolescents: a systematic review of the nature and mechanisms of the association

While many psychiatric disorders are associated with an increased risk for suicidal behaviors (SB) in children and adolescents, a few studies have explored the role of clinical symptoms based on a dimensional approach. Irritability is seen as a marker, a general psychopathology, and a symptom of both externalizing and internalizing disorders. In this review, we are interested in determining whether and how irritability can predict SB in youth. First, we reviewed consistencies and variation in the literature linking irritability to suicidal ideation (SI) and suicide attempt (SA). Second, based on the available models, we proposed specific mechanistic pathways, whereby irritability may modulate the risk for SB. Irritability has been found associated with SB both in cross-sectional and in longitudinal studies. The relation is consistent in different settings (i.e., general population and clinical settings) and across psychiatric disorders. The association is reduced but persists after adjusting for psychiatric disorder, including depression. On one hand, irritability constitutes a risk factor for SI via the onset of internalized disorder. On the other hand, irritable youth may be more prone to attempt suicide when experiencing SI. The measures for irritability were heterogeneous. A limited number of studies were designed to explore the role of mediators and/or moderators. Recognizing irritability in children and adolescents is a key issue with regards to suicide prevention.

On Defining Irritability and its Relationship to Affective Traits and Social Interpretations

Irritability has gained recognition as a clinically significant trait in youth and adults that when persistent and severe, predicts poor outcomes throughout life. However, its definition, measurement, and relationship to similar constructs remain poorly understood. In a community sample of adults (N=458; 19-74 years; M=40.5), we sought to identify a unitary irritability factor from independently constructed self-reported measures of irritability distinct from the related constructs of aggression, depression, and anxiety, and whether it was associated with face emotion identification deficits and hostile interpretation biases previously established in clinical pediatric samples. The three measures of irritability generated a common factor characterized by a rapid, angry response to provocation. This irritability factor had unique associations with tendencies to judge ambiguous stimuli as reflecting hostility, but not with face emotion identification performance. These findings clarify the nature of irritability and its associations with neurocognitive phenomenon.

Pathways of Association Between Childhood Irritability and Adolescent Suicidality

OBJECTIVE

Childhood irritability predicts suicidal ideation/attempt (suicidality), but it is unclear whether irritability is an independent and direct risk factor for suicidality or a marker of intermediate mental health symptoms associated with suicidality. This study aimed to identify developmental patterns of childhood irritability and to test whether childhood irritability is directly associated with suicidality or indirectly associated with intermediate mental health symptoms.

METHOD

One thousand three hundred ninety-three participants from the Québec Longitudinal Study of Child Development were followed from birth to 17 years. Teachers assessed irritability yearly (at 6-12 years) and children self-reported intermediate mental health symptoms (depression, anxiety, disruptiveness, and hyperactivity-impulsivity; at 13 years) and suicidality (at 15 and 17 years).

RESULTS

Four irritability trajectories were identified: low (74.7%), rising (13.0%), declining (7.4%), and persistent (5.0%). Children following a rising irritability trajectory (versus a low trajectory) were at higher suicidality risk. A large proportion of this association was direct (odds ratio 2.11, 95% CI 1.30-3.43) and a small proportion was indirect by depressive symptoms (accounting for 23% of the association; odds ratio 1.17, 95% CI 1.03-1.34). Children on a persistent irritability trajectory (versus a low trajectory) were at higher risk of suicidality and this association was uniquely indirect by depressive symptoms (accounting for 73% of the association; odds ratio 1.51, 95% CI 1.16-1.97). The declining trajectory was not related to suicidality; no association with anxiety, disruptiveness, and hyperactivity-impulsivity was found.

CONCLUSION

Rising irritability across childhood represents a direct risk for suicidality. Persistent irritability appears to be a distal marker of suicidality acting through more proximal depressive symptoms.

Association between irritability and suicide-related outcomes across the life-course. Systematic review of both community and clinical studies

BACKGROUND

Irritability is gaining considerable attention as a risk factor for suicide-related outcomes (suicide mortality, attempt, and ideation). However, the evidence of this association is scant. We conducted a systematic review of the evidence regarding the associations between irritability and suicide-related outcomes across the life-course.

METHODS

We conducted a systematic search on Medline and PsycINFO (up to January 2018) for original articles published in English investigating the association between irritability and suicide-related outcomes. Two researchers independently screened the articles, assessed the quality of the evidence (New-Castle-Ottawa Scale) and extracted study characteristics.

RESULTS

Thirty-nine studies were retrieved, most were of low/medium quality. Twelve assessed irritability in childhood/adolescence (6 in community samples, 6 in clinical samples) and 27 in adulthood (7 in community samples, 20 in clinical samples). In both childhood/adolescence and adult samples, most community-based studies reported a positive association between irritability and suicidal ideation and/or attempt, while clinical studies reported mixed findings. More specifically, in clinical studies, the association of irritability with suicide-related outcomes (i) was not supported among adult depressed patients, (ii) findings were inconsistent in adult bipolar patients, (iii) for inpatients/outpatients with various psychiatric disorders/conditions, association was observed in adulthood but not in childhood/adolescence.

LIMITATIONS

Differences in methodology and definition/measurement of irritability limited the comparability of included studies.

CONCLUSIONS

Although irritability has been proposed as a promising transdiagnostic factor associated with suicide-related outcomes, the absence of consensus in the definition of irritability (vs anger or reactive/impulsive aggression), the poor methodological quality, and the lack of developmental considerations mitigate the conclusions.