Empathy, mentalizing, and cognitive functioning in anorexia nervosa and bulimia nervosa

Childhood adversity and empathy in eating disorders: Exploring transdiagnostic profiles and socio-emotional functioning

BACKGROUND

Adverse childhood experiences (ACEs), including abuse and neglect, have been associated with difficulties in developing empathy. People with eating disorders (EDs) often report higher rates of ACE and display empathy-related impairments, which may contribute to maladaptive interpersonal functioning.

OBJECTIVE

This study explored the associations between childhood adversities and empathy-related outcomes in individuals with ED compared to a general population sample (GP).

PARTICIPANTS AND SETTING

Participants included 210 people with EDs (94 anorexia nervosa restrictive, 34 binge-purge anorexia nervosa, 36 bulimia nervosa, 36 binge-eating disorder, 24 OSFED) from national ED clinics and 151 participants from the GP.

METHODS

Participants completed the Childhood Trauma Questionnaire (CTQ) and the Empathy Quotient (EQ). Multivariate analyzes evaluated group differences and associations between specific forms of childhood adversity and subdomains of EQ: cognitive empathy (CE), emotional reactivity (ER) and social skills (SS).

RESULTS

ACEs were more prevalent in the ED group (56 %) than in the GP (33 %, χ2 = 31.81, p < 0.001). Emotional abuse and neglect were associated with a lower ER and SS, and physical neglect was associated with a reduction in CE and ER. No significant effects for physical or sexual abuse. Group membership alone was not associated with empathy outcomes. Cluster analysis identified two profiles: one with high trauma exposure and lower empathy, and another with lower trauma and more preserved socio-emotional functioning.

CONCLUSION

Findings highlight the specific impact of emotional forms of childhood adversity on empathy in EDs and support trauma-informed, individualized interventions based on socio-emotional profiles.

More empathy for others, more hurt for oneself? Empathy for pain is related to poor mental health and negative emotion regulation

BACKGROUND

Empathy for pain refers to a simulation of pain experiences evoked when seeing others in pain. Empathy for pain (vicarious pain) responders make up 27% of the healthy population, and are divided into two subsets: Sensory/Localized responders who feel localized physical pain and Affective/General responders who experience diffuse emotional pain. Empathy for pain is linked to pro-social behavior but can increase mental health symptoms.

METHODS

Multivariate analysis of variance and latent variable mediation model were used to investigate the relationship between empathy for pain, mental health, and emotion regulation based on a university student dataset (mainly Caucasian) from 2020 to 2021.

RESULTS

(1) Responders express significantly higher anxiety and somatization than non-responders, with Sensory/Localized responders reporting the greatest somatic concerns; (2) Sensory/localized responders show significantly higher depression than non-responders; (3) Two responder groups don't differ from non-responders on most positive emotional regulation strategies, but use more negative strategies (self-blame, rumination, and catastrophizing). (4) negative emotional regulation fully mediates the link between empathy and mental health.

CONCLUSIONS

These findings reveal a previously unrecognized link between empathy for pain and mental health, mediated by the increased use of negative emotion regulation strategies among responders. Our findings have particular implications for the mental health of empathic individuals or people who are often exposed to the pain of others (counselor or nurse, etc.).

Autism spectrum disorder and anorexia nervosa: Investigating the behavioural and neurocognitive overlap

Autism spectrum disorder (autism) and anorexia nervosa (AN) share many clinical features. Two key neurocognitive correlates of the autistic dyad, specifically, mentalising (social impairment) and set-shifting (restricted and repetitive behaviours/interests [RRBI]) were investigated in a sample of 327 adult participants with autism (n = 100; 50 females, 50 male), AN (n = 82; 54 females, 28 male), autism and AN (n = 45; 36 females, 9 male), and 100 (50 female, 50 male) control participants from the general population. A battery of self-report (Autism Spectrum Quotient, Eating Disorder Examination Questionnaire, Reflective Function Questionnaire, and Repetitive Behaviour Questionnaire 2 - Adult version) and performance-based (Wisconsin Card Sort Task [WCST] and Penn Emotion Recognition Test [ER-40]) measures were administered online. Clinical participants reported greater mentalising difficulty, more repetitive behaviour, and displayed worse mentalising ability compared to controls, with no difference between the clinical groups. Eating disorder psychopathology predicted error (total and perseverative) rates on the WCST, while lower levels of autistic traits were positively associated with ER-40 accuracy. We provide evidence that clinical features of autism and AN might have specific neurocognitive relevance. Improved understanding of the mechanisms underlying the overlapping features of autism and AN can have critical implications for early detection and improved and tailored intervention.

Theory of mind abilities during the course of bipolar disorder: A longitudinal study using mixed models

Theory of mind (ToM) deficits, difficulties in recognizing the intentions, propensities, and beliefs of others have been shown in individuals with bipolar disorder in several studies; however, it is not yet elucidated how ToM abilities changes over the course of bipolar disorder and is related to illness symptoms. This is one of the first longitudinal studies to compare the ToM abilities of euthymic bipolar individuals and healthy controls over a four and a half years period. ToM abilities were measured using the Reading the Mind in the Eyes Test (RMET). A total of 91 euthymic bipolar individuals and 91 healthy controls were included in the analyses. Linear mixed models were used to compare ToM abilities of bipolar individuals and healthy controls. It was found that bipolar individuals scored lower on average on the RMET than healthy controls and that these RMET scores were stable over four and a half years. The results of this study suggest that ToM deficits are a stable (possibly endophenotypic) trait of bipolar disorder. This understanding can contribute to better identification, assessment, and treatment strategies for individuals with bipolar disorder, ultimately improving their overall care and outcome.

Attachment, Mentalization, Emotion Dysregulation, and Empathy in Eating Disorders: Comparing Anorexic and Bulimic Patients

ABSTRACT

Eating disorders (EDs) represent a wide range of clinical symptoms related to food intake, body image, and weight issues, and include anorexia nervosa-restricting type (AN-R), anorexia nervosa-binge-purge type (AN-BP), and bulimia nervosa (BN). The aim was to investigate the characteristics of attachment, mentalization, emotion dysregulation, and empathy in a sample of 102 patients with EDs. A sample of 102 patients and therapists completed a series of measures for the assessment of ED pathology, mentalization, empathy, and emotion dysregulation. Pearson correlations and analysis of variance were used to test the characteristics of the variables among the groups. In relation to attachment and emotion dysregulation, no significant differences were found. In relation to mentalization, significant difference in good mentalization was found in AN-R subtype compared with the BN subtype. In relation to empathy, results showed significantly lower scores in BN subtype on affective empathy compared with the AN-BP subtype, and in AN-R subtype on cognitive empathy. Finally, we used Z -scores for each item ranked by value (higher to lower) to develop different clinical prototypes for each group. Our results point toward the clinical need to address the assessed variables, specifically mentalization, emotion dysregulation, and empathy, in the diagnosis and treatment of EDs.

Cognitive and emotional empathy in acute and remitted anorexia nervosa: a systematic review

Background

Impairments in empathy are well established in anorexia nervosa (AN). It is unclear, however, whether these deficits only occur in the acute phases of AN due to neurocognitive impacts of starvation (often referred to as context-dependent, or state-like), or if deficits remain once remission has been achieved (trait-like). This debate is commonly referred to as the 'state vs trait' debate.

Objective

This systematic review aims to summarise existing literature regarding empathy in AN, and to investigate whether empathy deficits in AN are state- or trait-based.

Method

A total of 1014 articles were identified, and seven articles remained after the screening process. These seven articles, comparing empathy across three groups (acute AN, remission of AN, and non-clinical controls), were evaluated and summarised in accordance with PRISMA guidelines. Articles were required to have included all three groups and report on either cognitive empathy and/or emotional empathy.

Results

The majority of studies were of satisfactory quality. The results identified were inconsistent, with few articles lending some support to the 'state' hypothesis and others producing nonsignificant results.

Conclusions

There is minimal literature comparing empathy in acute and remission phases of AN. While there were some inconsistencies in included articles, some data indicate that there may be slight improvements to emotional and cognitive empathy following recovery of AN. Further research is needed to better enrich knowledge regarding the role of state vs trait with regard to neurocognitive difficulties experienced by individuals with AN.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=335669, identifier CRD42022335669.

Diminished Adaptation, Satisfaction, and Neural Responses to Advantageous Social Signals in Anorexia Nervosa and Bulimia Nervosa

BACKGROUND

Development and recurrence of 2 eating disorders (EDs), anorexia nervosa and bulimia nervosa, are frequently associated with environmental stressors. Neurobehavioral responses to social learning signals were evaluated in both EDs.

METHODS

Women with anorexia nervosa (n = 25), women with bulimia nervosa (n = 30), or healthy comparison women (n = 38) played a neuroeconomic game in which the norm shifted, generating social learning signals (norm prediction errors [NPEs]) during a functional magnetic resonance imaging scan. A Bayesian logistic regression model examined how the probability of offer acceptance depended on cohort, block, and NPEs. Rejection rates, emotion ratings, and neural responses to NPEs were compared across groups.

RESULTS

Relative to the comparison group, both ED cohorts showed less adaptation (p = .028, ηp2 = 0.060), and advantageous signals (positive NPEs) led to higher rejection rates (p = .014, ηp2 = 0.077) and less positive emotion ratings (p = .004, ηp2 = 0.111). Advantageous signals increased neural activations in the orbitofrontal cortex for the comparison group but not for women with anorexia nervosa (p = .018, d = 0.655) or bulimia nervosa (p = .043, d = 0.527). More severe ED symptoms were associated with decreased activation of dorsomedial prefrontal cortex for advantageous signals.

CONCLUSIONS

Diminished neural processing of advantageous social signals and impaired norm adaptation were observed in both anorexia nervosa and bulimia nervosa, while no differences were found for disadvantageous social signals. Development of neurocognitive interventions to increase responsivity to advantageous social signals could augment current treatments, potentially leading to improved clinical outcomes for EDs.

Empathy and Violence in Schizophrenia and Antisocial Personality Disorder

A paucity of cognitive and affective features of empathy can be correlated with violent behavior. We aimed to identify differences in empathy among four groups in a sample of 100 male participants: (1) 27 violent offenders with schizophrenia, (2) 23 nonviolent patients with schizophrenia, (3) 25 patients with antisocial personality disorder, and (4) 25 subjects from the general population, who formed the control group. Schizophrenia symptoms were quantified with the Positive and Negative Syndrome Scale. Empathy was measured with the empathy quotient. Theory of mind was evaluated using (a) the first-order false-belief task, (b) the hinting task, (c) the faux pas recognition test and (d) the "reading the mind in the eyes" test (revised). Differences noted among the groups were age (controls were younger) and educational status (antisocials were less educated). The empathy quotient scoring (p < 0.001) and theory-of-mind tests (p < 0.001) were distinct between the control group and the three other groups of participants, but not among the three patient groups. Patients with antisocial personality disorder, violent psychotic offenders and psychotic nonviolent patients show no remarkable differences in affective or cognitive empathy tests, but they all present deficits in empathy and theory of mind when compared to controls.

Exploring the role of autistic traits and eating disorder psychopathology on mentalising ability in the general population

BACKGROUND

This study evaluated the role of overlapping traits and characteristics related to autism spectrum disorder (autism) and anorexia nervosa (AN) in the general population, and the impact of these traits on mentalising ability.

METHODS

A sample of young adults (N = 306), aged 18-25 years, was recruited to complete an online study that consisted of 4 measures: the Autism-Spectrum Quotient, Eating Disorder Examination Questionnaire, the Mentalization Scale, and the Reading the Mind in the Eyes task.

RESULTS

Higher levels of autistic traits, particularly difficulty with attention switching, were associated with increased eating disorder psychopathology. Overall, autistic traits and eating disorder psychopathology were related among females, but not males. Difficulty with attention switching, however, was related to eating disorder psychopathology among both females and males. Autistic traits also appear to have a greater role in mentalising ability than does eating disorder psychopathology.

CONCLUSION

The role of attention switching in overlapping traits of autism and eating disorder psychopathology needs to be more comprehensively evaluated by future research, as does the role of biological sex. Expanded knowledge in this field will help to better understand and evaluate symptoms at presentation, leading to clearer diagnoses and potentially better treatment outcomes.

A multidimensional examination of affective and cognitive empathy in anorexia nervosa

Socio-emotional features are crucial in the development and maintenance of anorexia nervosa (AN). The present study investigates the patterns of altered and preserved empathic abilities in AN. Empathy is an umbrella term that comprises the ability to recognise another's emotional state, take another's perspective, and fantasise (cognitive empathy), as well as the ability to experience vicarious emotions and signal them (affective empathy). These empathic abilities were measured in 43 AN patients and 33 healthy women through a multi-method approach comprising self-report measures, behavioural tasks and bodily correlates. Further, we assessed self-reported approach-avoidance attitudes towards suffering others. Results showed that, within the domain of cognitive empathy, AN patients reported impairment in recognising emotional expressions of anger and fantasising. Concerning affective empathy, they manifested lower sharing of others' positive emotions, higher self-reported distress, and higher facial expressiveness during a video depicting a suffering person. Finally, AN patients reported lower motivation to approach suffering others. Our results draw a complex picture of preserved and altered empathic abilities in AN and capture which are the deficits mediated by the higher levels of anxiety and depression reported by the AN population and those that seem to persist independently from these co-morbid conditions.

Many Facets of Eating Disorders: Profiling Key Psychological Features of Anorexia Nervosa and Binge Eating Disorder

Objective. The present study employs a profile analysis to identify and compare psychological features and core eating disorder (ED) symptoms in clinical samples of patients with anorexia nervosa (AN) and binge eating disorder (BED) and the general population (GP). Methods. A sample comprising 421 participants (142 patients with AN; 139 patients with BED; and 140 participants from the GP) was surveyed with the Eating Disorder Inventory-3 (EDI-3). Individuals with AN and BED were recruited and tested during their first week of a multidisciplinary inpatient program for weight loss and rehabilitation at the 'Rete DCA USL Umbria 1' (Eating Disorders Services), Italy. Results. The findings suggest distinct patterns of symptom presentation between the three samples across all the EDI-3 dimensions-with both the AN and BED groups scoring significantly higher than the GP. Patients with AN registered greater scores in all the psychological trait scales and the drive for thinness ED-specific dimension of the EDI-3 compared with their BED counterpart-which, instead, scored higher in the bulimia and body dissatisfaction subscales. These data support the transdiagnostic nature of the main risk factors for the onset and maintenance of EDs-which would vary in severity levels-and the existence of disease-specific pathways giving rise to AN and BED. Conclusion. This study for the first time compares patients with AN and BED with a non-clinical sample on main ED psychological features. This might inform classification approaches and could have important implications for the development of prevention and early intervention programs.

Emotion recognition, alexithymia, empathy, and emotion regulation in women with anorexia nervosa

PURPOSE

Anorexia nervosa (AN) is associated with challenges in recognizing, understanding, and interpreting one's own and other's emotional states, feelings, and thoughts. It is unknown whether difficulties in emotion processing occur independently of common comorbid symptoms of AN and predict acute eating disorder characteristics. We aimed to examine emotion recognition, alexithymia, emotion regulation, and empathy in individuals with AN and to assess whether these predict eating disorder symptoms independently from comorbid symptoms.

METHODS

Participants included 42 women with AN and 40 healthy control (HC) women between 18-30 years. Basic and complex emotion recognition was assessed with face photos and video clips. Alexithymia, empathy, emotion regulation, and comorbid symptoms (anxiety, depressive, and obsessive-compulsive symptoms and ASD traits) were assessed with self-assessment questionnaires.

RESULTS

Participants with AN exhibited difficulties in basic and complex emotion recognition, as well as increased alexithymia, decreased empathy, and challenges in emotion regulation when compared to HCs. After controlling for comorbid symptoms, differences remained only in complex emotion recognition. Challenges in emotion recognition were associated with lower body mass index, and increased alexithymia was associated with increased eating disorder symptoms. Increased challenges in emotion regulation were associated with a shorter duration of illness, higher body mass index, and increased eating disorder symptoms.

CONCLUSIONS

Participants with AN displayed widespread deficit in emotion processing, but only challenges in complex emotion recognition occurred independently from comorbid symptoms. Deficits in emotion processing may contribute to the illness severity and thus could be an important treatment target.

LEVEL OF EVIDENCE

Level III, case-control analytic study.

Mechanisms by which adverse childhood experiences, other traumas and PTSD influence the health and well-being of individuals with eating disorders throughout the life span

BACKGROUND

Multiple published sources from around the world have confirmed an association between an array of adverse childhood experiences (ACEs) and other traumatic events with eating disorders (EDs) and related adverse outcomes, including higher morbidity and mortality.

METHODS

In keeping with this Special Issue's goals, this narrative review focuses on the ACEs pyramid and its purported mechanisms through which child maltreatment and other forms of violence toward human beings influence the health and well-being of individuals who develop EDs throughout the life span. Relevant literature on posttraumatic stress disorder (PTSD) is highlighted when applicable.

RESULTS

At every level of the pyramid, it is shown that EDs interact with each of these proclaimed escalating mechanisms in a bidirectional manner that contributes to the predisposition, precipitation and perpetuation of EDs and related medical and psychiatric comorbidities, which then predispose to early death. The levels and their interactions that are discussed include the contribution of generational embodiment (genetics) and historical trauma (epigenetics), social conditions and local context, the ACEs and other traumas themselves, the resultant disrupted neurodevelopment, subsequent social, emotional and cognitive impairment, the adoption of health risk behaviors, and the development of disease, disability and social problems, all resulting in premature mortality by means of fatal complications and/or suicide.

CONCLUSIONS

The implications of these cascading, evolving, and intertwined perspectives have important implications for the assessment and treatment of EDs using trauma-informed care and trauma-focused integrated treatment approaches. This overview offers multiple opportunities at every level for the palliation and prevention of EDs and other associated trauma-related conditions, including PTSD.

Affective cognition in eating disorders: a systematic review and meta-analysis of the performance on the "Reading the Mind in the Eyes" Test

BACKGROUND

The Reading the Mind in the Eyes Test (RMET) is listed in the National Institute of Mental Health's Research Domain Criteria as a tool apt to measure the understanding of others' mental states. People diagnosed with anorexia nervosa (AN) showed poorer performances on the RMET than healthy controls. Less data are available concerning other eating disorders.

METHODS

Systematic review of four major databases from inception to July 15, 2021 following the PRISMA guidelines. Meta-analysis of cross-sectional observational studies comparing the scores of the RMET between patients with eating disorders and age- and-gender matched control groups.

RESULTS

Out of 21 studies, we retrieved 29 independent samples of patients diagnosed with an eating disorder. Patients with active AN (n = 580) showed worse performances on the RMET than controls (n = 1019). Year of publication accounted for 61% of the (substantial: I2 = 81%) heterogeneity in the meta-analysis. Earlier studies were more likely to find worse performances on the RMET of patients with active AN than later studies. Patients with bulimia nervosa (n = 185) performed poorly as compared to controls (n = 249), but the results were not statistically significant on the random-effect model. Obese patients with binge-eating disorder (n = 54) did not differ on the RMET from obese controls (n = 52). Patients with eating disorder not otherwise specified (n = 57) showed minimal differences compared to controls (n = 96). Study quality was good in six studies only.

CONCLUSIONS

Patients with eating disorders do not suffer from an impaired understanding of others' mental states, except for a still-to-be-identified subgroup of patients with active AN.

LEVEL OF EVIDENCE

I, systematic review and meta-analysis.

Vicarious ratings of self vs. other-directed social touch in women with and recovered from Anorexia Nervosa

Anorexia Nervosa (AN) is an eating pathology characterized by restricted eating, body image distortions and impaired socio-cognitive abilities. Altered responses to affective touch—a pleasant interoceptive stimulus hypothesised to involve activation of the C-Tactile (CT) system, may contribute to the aetiology and maintenance of this disorder. Here, we investigated whether third-party social touch vicarious ratings of different body sites at CT-optimal vs. non-CT optimal velocities differed in women with and recovered from AN (RAN) and healthy controls (HCs). Thirty-five HCs, 27 AN and 29 RAN provided pleasantness ratings for two different tasks designed to probe expectations of how touch is perceived by self (self-directed touch) vs. others (other-directed touch). Findings revealed that both clinical groups, compared to HCs, did not differ in their pleasantness ratings to touch for another but when evaluating touch for self, both clinical groups rated CT-optimal touch as less pleasant than HCs. These findings suggest that AN and RAN women demonstrate an atypical vicarious pleasantness response to affective touch involving self, but not others. Novel therapeutic approaches that help anorexics to better interpret or improve tolerance of affective tactile experiences involving the self may be an important addition to current standard treatments.

Phonological working memory is adversely affected in adults with anorexia nervosa: a systematic literature review

PURPOSE

Cognitive restraint has potentiating and deleterious effects on working memory (WM) in anorexia nervosa (AN). Conflicting evidence may be due to heterogeneity of tasks examining different WM components (e.g., verbal/auditory versus visuospatial), and differences in adolescent versus adult AN. Additionally, differential cognitive profiles of restricting versus binge/purging subtypes, comorbid psychiatric disorders and psychotropic medication use may confound findings.

METHODS

To address these conflicts, 25 studies, published between 2016 and 2021, investigating WM in children, adolescents and adults with AN were systematically reviewed using PRISMA guidelines.

RESULTS

In 71% of WM tasks, no difference in performance between AN patients and age-matched controls was reported, while 29% of WM tasks showed worse performance. Adults with AN displayed deficits in 44% of the verbal/auditory tasks, while performance remained unaffected in 86% of visuospatial tasks.

CONCLUSION

Examining age groups and WM subsystems separately revealed novel findings of differentially affected WM components in AN. Comorbidities and psychotropic medications were common among AN participants and should be regarded as critical confounding factors for WM measures. Future studies examining different components of WM, acknowledging these confounding factors, may reveal specific deficits in AN to aid treatment improvement strategies.

LEVEL OF EVIDENCE

I, systematic review.

A meta-analytic investigation of grey matter differences in anorexia nervosa and autism spectrum disorder

Recent research reports Anorexia Nervosa (AN) to be highly dependent upon neurobiological function. Some behaviours, particularly concerning food selectivity are found in populations with both Autism Spectrum Disorder (ASD) and AN, and there is a proportionally elevated number of anorexic patients exhibiting symptoms of ASD. We performed a systematic review of structural MRI literature with the aim of identifying common structural neural correlates common to both AN and ASD. Across 46 ASD publications, a meta‐analysis of volumetric differences between ASD and healthy controls revealed no consistently affected brain regions. Meta‐analysis of 23 AN publications revealed increased volume within the orbitofrontal cortex and medial temporal lobe, and adult‐only AN literature revealed differences within the genu of the anterior cingulate cortex. The changes are consistent with alterations in flexible reward‐related learning and episodic memory reported in neuropsychological studies. There was no structural overlap between ASD and AN. Findings suggest no consistent neuroanatomical abnormality associated with ASD, and evidence is lacking to suggest that reported behavioural similarities between those with AN and ASD are due to neuroanatomical structural similarities.

Findings related to neuroanatomical structure in AN/ASD demonstrate overlap and require revisiting.

Meta‐analytic findings show structural increase/decrease versus healthy controls (LPFC/MTL/OFC) in AN, but no clusters found in ASD.

The neuroanatomy associated with ASD is inconsistent, but findings in AN reflect condition‐related impairment in executive function and sociocognitive behaviours.

Trait-Based Dimensions Discriminating Adults with Attention Deficit Hyperactivity Disorder (ADHD), Autism Spectrum Disorder (ASD) and, Co-occurring ADHD/ASD

This study assessed the co-occurrence of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in newly diagnosed adults of normal intelligence and the contribution of trait-based dimensions deriving from the Barkley Adult ADHD Rating Scale-IV (BAARS-IV), the Autism-Spectrum Quotient (AQ), and the Empathy Quotient (EQ) to the differentiation of patients with ADHD, ASD, and ADHD/ASD. A total of 16.1% of patients with ADHD received a co-occurring ASD diagnosis, while 33.3% of patients with ASD received an ADHD diagnosis. Subjects with ADHD or ADHD/ASD had higher scores in all ADHD traits compared to ASD subjects. Compared to the ADHD group, the ASD group had AQ scores that were significantly greater, except for attention to detail. ADHD/ASD co-occurrence significantly increased the score of attention to detail. The total EQ score was greater in the ADHD group. In the stepwise logistic regression analyses, past hyperactivity, current inattention and impulsivity, attention switching, communication, imagination, and total EQ score discriminated ADHD patients from ASD patients. Attention to detail, imagination, and total EQ score discriminated ADHD cases from ADHD/ASD cases, while past hyperactivity and current impulsivity discriminated ASD subjects from ADHD/ASD subjects. Our findings highlight the importance of particular trait-based dimensions when discriminating adults with ADHD, ASD, and co-occurring ADHD/ASD.