The relationship between alexithymia and theory of mind: A systematic review

Alexithymia in radiologically isolated syndrome

BACKGROUND

Alexithymia refers to difficulty identifying (DIF) and describing (DDF) feelings and externally oriented thinking (EOT). Its prevalence remains unknown in the radiologically isolated syndrome (RIS), the preclinical multiple sclerosis (MS) phase.

METHODS

Alexithymia was measured with the Toronto Alexithymia Scale (TAS-20) in 29 RIS and age and gender-matched healthy controls and relapsing-remitting (RR) MS with an EDSS <3. All participants completed evaluations of cognition (BCCOG-SEP), depression (Fast-BDI), fatigue (EMIF), and quality of life (SEP-59).

RESULTS

The level of alexithymia was significantly different between the three groups, with the higher score in the RRMS group (mean score of 54.5, SD: 12,3) compared to RIS (mean score of 47.2, SD: 14.8) and in healthy controls (mean score of 41.9, SD:12.8). 34 % of RIS participants showed a pathological level of alexithymia. The proportions were 21.7 % in the healthy controls and 51.7 % in the RRMS-matched groups. The difference was mainly significant for the DIF factor, p<.001. No significant correlations were observed between alexithymia and the different measures of cognition. In the RIS group, alexithymia was strongly linked to the levels of depression and cognitive fatigue. Furthermore, alexithymia was related to decreased mental quality of life.

CONCLUSION

The study revealed that one-third of subjects with radiologically isolated syndrome show signs of alexithymia. Interestingly, no cognitive measure was found to be correlated with the level of alexithymia, which is consistent with previous research findings. Alexithymia and mainly difficulty identifying feelings in RIS are associated with depression but also relate to cognitive fatigue and reduced mental quality of life. This could impact the daily interactions of RIS subjects.

Childhood language development and alexithymia in adolescence: an 8-year longitudinal study

Alexithymia (difficulties identifying and describing feelings) predicts increased risks for psychopathology, especially during the transition from childhood to adolescence. However, little is known of the early contributors to alexithymia. The language hypothesis of alexithymia suggests that language deficits play a primary role in predisposing language-impaired groups to developing alexithymia; yet longitudinal data tracking prospective relationship between language function and alexithymia are scarce. Leveraging data from the Surrey Communication and Language in Education cohort (N = 229, mean age at time point 1 = 5.32 years, SD = 0.29, 51.1% female), we investigated the prospective link between childhood language development and alexithymic traits in adolescence. Results indicated that boys with low language function at ages 4-5 years, and those who later met the diagnostic criteria for language disorders at ages 5-6 years, reported elevated alexithymic traits when they reached adolescence. Parent-reported child syntax abilities at ages 5-6 years revealed a dimensional relationship with alexithymic traits, and this was consistent with behavioral assessments on related structural language abilities. Empirically derived language groups and latent language trajectories did not predict alexithymic traits in adolescence. While findings support the language hypothesis of alexithymia, greater specificity of the alexithymia construct in developmental populations is needed to guide clinical interventions.

Is self-awareness necessary to have a theory of mind?

Forty years ago, Gallup proposed that theory of mind presupposes self-awareness. Following Humphrey, his hypothesis was that individuals can infer the mental states of others thanks to the ability to monitor their own mental states in similar circumstances. Since then, advances in several disciplines, such as comparative and developmental psychology, have provided empirical evidence to test Gallup's hypothesis. Herein, we review and discuss this evidence.

Suicidal ideation in Chinese patients with chronic schizophrenia: prevalence, clinical correlates, and relationship with alexithymia

Suicidal ideation (SI) is common among people with schizophrenia. However, it has received less attention than suicide attempts (SA), especially in the Chinese population. Alexithymia is a well-established risk factor for SI across different populations. Nevertheless, very few studies evaluated their relationship in schizophrenia patients. We aimed to determine the prevalence and clinical correlates of SI and its relationship with alexithymia in 812 Chinese chronic schizophrenia inpatients. We assessed SI, clinical symptoms, and alexithymia by the Beck Scale for Suicidal Ideation, the Positive and Negative Syndrome Scale (PANSS), and the Toronto Alexithymia Scale, respectively. A multiple logistic regression model was conducted to identify independent correlates of SI. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were performed to determine the ability of our model to distinguish between patients with and without SI. 10% (n = 84) reported current SI. Lifetime SA (OR, 4.68; 95% CI 2.76-7.94, p < 0.001), PANSS depressive factor (OR, 1.24; 95% CI 1.12-1.38, p < 0.001), PANSS positive subscale (OR, 1.055; 95% CI 1.004-1.108, p = 0.035), and difficulty identifying emotions (OR, 1.07; 95% CI 1.03-1.12, p = 0.002) were associated with SI. The AUC value was 0.80, indicating excellent distinguishing capabilities. Timely assessments of these factors may help identify schizophrenia patients who are at risk for SI.

An fMRI study on alexithymia and affective state recognition in the Reading the Mind in the Eyes Test

Recognizing others' affective states is essential for successful social interactions. Alexithymia, characterized by difficulties in identifying and describing one's own emotions, has been linked to deficits in recognizing emotions and mental states in others. To investigate how neural correlates of affective state recognition are affected by different facets of alexithymia, we conducted a functional magnetic resonance imaging study with 53 healthy participants (aged 19-36 years, 51% female) using the Reading the Mind in the Eyes Test (RMET) and three different measures of alexithymia [Toronto Structured Interview for Alexithymia (TSIA), Toronto Alexithymia Scale (TAS-20), and Bermond-Vorst Alexithymia Questionnaire]. In addition, we examined brain activity during the RMET and replicated previous findings with task-related brain activation in the inferior frontal and temporal gyri, as well as the insula. No association was found between alexithymia and behavioral performance in the RMET, possibly due to the low number of participants with high alexithymia levels. Region of interest based analyses revealed no associations between alexithymia and amygdala or insula activity during the RMET. At the whole-brain level, both a composite alexithymia score and the unique variance of the alexithymia interview (TSIA) were associated with greater activity in visual processing areas during the RMET. This may indicate that affective state recognition performance in alexithymia relies on a higher compensatory activation in visual areas.

Poorer representation of minds underpins less accurate mental state inference for out-groups

Societies are becoming more polarised, driven in part by misconceptions about out-groups' beliefs. To understand these effects, one must examine the cognitive processes underlying how people think about others. Here, we investigate whether people are less prone to theorise about the minds of out-groups, or less able to do so. Participants (Study 1: n = 128; Study 2: n = 128) made inferences about social and political beliefs held by real in-group and out-group members, and could choose to receive further information to improve these inferences. Results show: (1) participants sought equivalent or greater information about out-groups relative to in-groups; but despite this, (2) made significantly less accurate inferences for out-groups; and (3) were significantly less aware of their reduced ability. This shows that poorer mental state inference is not underpinned by a reduced propensity to consider out-group minds, but instead by a worse representation of the minds of out-groups.

'The Relationship Between Childhood Traumas and Social Cognition Through Theory of Mind and Alexithymia in Bipolar Disorder'

This study aimed to investigate the potential differences in childhood trauma (CT), theory of mind (ToM), a significant component of social cognition, and alexithymia in bipolar disorder (BD) patients and healthy controls. The study included 50 BD patients who met the study criteria and were under follow-up at our clinic along with 50 healthy controls. The two groups were matched for age, gender, and educational status. A sociodemographic questionnaire, Childhood Trauma Questionnaire (CTQ), Toronto Alexithymia Scale (TAS), Dokuz Eylul Theory of Mind Index (DEZIKO), Hamilton Depression Rating Scale (HDRS), and Young Mania Rating Scale (YMRS) were applied to all participants. The CTQ-Total, TAS total, and DEZIKO total scores were significantly higher in the BD group compared to the healthy group (p < .001). A significant positive correlation was identified between the TAS total score and CTQ physical neglect (r = 0.472, p = .001), CTQ emotional neglect (r = 0.449, p = .001) and CTQ total scores (r = 0.5, p < .001) in the BD group. A statistically significant negative correlation was identified between the DEZIKO faux pas score and the CTQ physical neglect score (r = -0.437, p = .002). BD patients had more adverse childhood experiences, lower ToM abilities despite being in remission, and more pronounced alexithymic personality features compared to healthy controls. We also identified a relationship between ToM, alexithymia, and adverse childhood experiences in BD.

No association between alexithymia and emotion recognition or theory of mind in a sample of adolescents enhanced for autistic traits

LAY ABSTRACT

Alexithymia is a sub-clinical condition characterised by difficulties identifying and describing one's own emotions, which is found in many, but not all autistic people. The alexithymia hypothesis suggests that certain aspects of socio-cognitive functioning typically attributed to autism, namely difficulties in emotion recognition, might be better explained by often co-occurring alexithymia. It is important to understand what is specific to autism and what is due to other co-occurring characteristics to develop appropriate support for autistic people. However, most research on this topic has been conducted in adults, which limits our knowledge about the relevance of this theory to younger autistic populations. This study tested whether difficulties in emotion recognition and theory of mind traditionally associated with autism might be better explained by alexithymia in a sample of adolescents with and without a diagnosis of autism. Results found that difficulties in emotion recognition and theory of mind were both associated with autistic traits, and this was not accounted for by individual differences in levels of alexithymia. This research suggests that more work is needed to understand the applicability of the alexithymia hypothesis in younger populations, but that at least in adolescents and when using parent-report measures, alexithymia may not account for emotion recognition or theory of mind difficulties associated with autistic traits.

Measures of individual differences in adult theory of mind: A systematic review

Theory of mind (ToM), the ability to understand and reason about mental states, has been extensively studied in young children and clinical populations. A growing interest in examining ToM in adults has emerged over the past two decades, but the extent to which existing measures are suitable for studying adults, especially in detecting individual differences, remains understudied. In this systematic review of 273 studies, 75 measures used to investigate individual differences in adults' ToM were identified. Their sensitivity to individual differences, reliability, and validity were examined. Results suggest that ceiling effects were prevalent, and there was limited evidence to establish the reliability or validity of these measures due to the lack of reports of psychometric properties. Interrelations among measures were inconsistent. These findings highlight the need for future empirical and theoretical work to broaden the evidence base regarding psychometric properties of measures, to develop new measures, and to lay out more specific hypotheses about the relevance of ToM for different social outcomes.

Alexithymia in Chinese patients with chronic schizophrenia: Prevalence, clinical correlates, and relationship with neurocognition and empathy

INTRODUCTION

Alexithymia is highly prevalent and strongly related to adverse consequences in patients with schizophrenia. However, its associated factors remain largely unexplored. The present study aimed to determine the prevalence of alexithymia and its association with sociocultural characteristics, clinical symptoms, neurocognition, and empathy in 854 Chinese patients with schizophrenia.

METHOD

Demographic information was collected through a self-designed questionnaire. Alexithymia was assessed by the Toronto Alexithymia Scale (TAS-20). We assessed clinical symptoms, neurocognition, and empathy via the following instruments: Positive and Negative Syndrome Scale, Repeatable Battery for the Assessment of Neuropsychological Status, and Interpersonal Reactivity Index. A multiple logistic regression model was conducted to determine the independent correlates of alexithymia.

RESULTS

Approximately one-third (n = 277, 32%) of patients with schizophrenia had alexithymia. Patients with alexithymia had significantly more severe negative symptoms, neurocognition, and empathy impairment than patients without alexithymia. Being male, negative symptoms, personal distress, empathic concern, and language functioning were independently associated with alexithymia.

DISCUSSION

Our findings demonstrate a high prevalence of alexithymia and its strong association with clinical symptoms, neurocognition, and empathy, which calls for timely screening and intervention for alexithymia in patients with schizophrenia. Targeting impaired language function, negative symptoms, and impaired affective empathy might help reduce alexithymia and its related negative consequences.

What is the relationship between alexithymia and experiential avoidance? A latent analysis using three alexithymia questionnaires

Alexithymia is a clinically relevant personality trait characterized by poor emotional awareness and associated with several psychological and physical health concerns. Individuals with high alexithymia tend to engage in experiential avoidance and this may mediate psychological distress. However, little is known about what specific processes of experiential avoidance are involved, and the nature of the relation between alexithymia, experiential avoidance, and psychological distress remains unclear at a latent construct level. To examine this relationship at the latent construct level, a representative sample of 693 U.S. adults completed alexithymia (TAS-20, BVAQ, PAQ), general distress (DASS-21), multi-dimensional experiential avoidance (MEAQ), and general health (PROMIS-G-10) questionnaires. Structural equation modeling revealed that alexithymia significantly predicted experiential avoidance (β = 0.966, t = 82.383, p < .01), experiential avoidance significantly predicted general distress (β = 0.810, t = 2.017, p < .05), and experiential avoidance fully mediated the relationship between alexithymia and general distress (βindirect = -0.159, t = -0.398, p > .05). Correlations between alexithymia and experiential avoidance subfactors revealed a strong relationship to the repression and denial subfactor. Experiential avoidance is a promising target for clinical interventions, though longitudinal research is necessary to elucidate how the relationship between alexithymia and experiential avoidance unfolds over time.

Dissociating cognitive and affective empathy across psychopathy dimensions: The role of interoception and alexithymia

This study examined the associations between psychopathy dimensions (triarchic phenotypes and classical factors), empathy domains (cognitive and affective), and interoception (interoceptive attention and accuracy) while accounting for the putative role of alexithymia. A community sample (n = 515) completed an online survey encompassing: Triarchic Psychopathy Measure (boldness, meanness, disinhibition); Levenson Self-Report Psychopathy Scale (primary and secondary psychopathy); Body Perception Questionnaire (interoceptive attention); Interoceptive Accuracy Scale; Toronto Alexithymia Scale. Hierarchical linear regression models were implemented for hypothesis-driven analyses examining the associations between psychopathy, empathy, and interoception while controlling for sex, age, and alexithymia. Exploratory path models were employed to investigate alexithymia and/or cognitive empathy as mediators between interoception and psychopathy. Our results largely confirmed the postulated empathy profiles across psychopathy dimensions, as meanness and primary psychopathy displayed a broad empathy impairment, while disinhibition and secondary psychopathy were only associated with diminished cognitive empathy. Importantly, boldness displayed a unique pattern (enhanced cognitive empathy and reduced affective empathy), further reinforcing its importance within the constellation of psychopathy traits. Contrary to our hypotheses, self-perceived interoceptive attention and accuracy were not associated with either psychopathy dimension after controlling for alexithymia. However, interoceptive accuracy and alexithymia were associated with cognitive empathy, while alexithymia was also positively related to all psychopathy dimensions (as expected), despite the unexpected strong and negative association with boldness. Exploratory analyses suggested significant indirect effects (mediation) between interoceptive accuracy and psychopathy via alexithymia and/or cognitive empathy. These mediating effects must be interpreted with caution and future studies should be designed to formally test this model.

Designing a neuroclinical assessment of empathy deficits in psychopathy based on the Zipper Model of Empathy

Ho, M.H., Kemp, B.T., Eisenbarth, H. & Rijnders, R.J.P. Designing a neuroclinical assessment of empathy deficits in psychopathy based on the Zipper Model of Empathy. NEUROSCI BIOBEHAV REV YY(Y) XXX-XXX, 2023. The heterogeneity of the literature on empathy highlights its multidimensional and dynamic nature and affects unclear descriptions of empathy in the context of psychopathology. The Zipper Model of Empathy integrates current theories of empathy and proposes that empathy maturity is dependent on whether contextual and personal factors push affective and cognitive processes together or apart. This concept paper therefore proposes a comprehensive battery of physiological and behavioral measures to empirically assess empathy processing according to this model with an application for psychopathic personality. We propose using the following measures to assess each component of this model: (1) facial electromyography; (2) the Emotion Recognition Task; (3) the Empathy Accuracy task and physiological measures (e.g., heart rate); (4) a selection of Theory of Mind tasks and an adapted Dot Perspective Task, and; (5) an adjusted Charity Task. Ultimately, we hope this paper serves as a starting point for discussion and debate on defining and assessing empathy processing, to encourage research to falsify and update this model to improve our understanding of empathy.

Hormonal abnormalities in alexithymia

Alexithymia is a personality trait characterized by difficulties in emotion recognition and regulation that is associated with deficits in social cognition. High alexithymia levels are considered a transdiagnostic risk factor for a range of psychiatric and medical conditions, including depression, anxiety, and autism. Hormones are known to affect social-emotional cognition and behavior in humans, including the neuropeptides oxytocin and vasopressin, the steroid hormones testosterone and estradiol, the stress hormone cortisol as well as thyroid hormones. However, few studies have investigated hormonal effects on alexithymia and on alexithymia-related impairments in emotion regulation and reactivity, stress response, and social cognition. Here, we provide a brief overview of the evidence linking alexithymia to abnormalities in hormone levels, particularly with regard to cortisol and oxytocin, for which most evidence exists, and to thyroid hormones. We address the current lack of research on the influence of sex hormones on alexithymia and alexithymia-related deficits, and lastly provide future directions for research on associations between hormonal abnormalities and deficits in emotion regulation and social cognition associated with alexithymia.

Novel theory of mind task demonstrates representation of minds in mental state inference

Theory of mind (ToM), the ability to represent the mental states of oneself and others, is argued to be central to human social experience, and impairments in this ability are thought to underlie several psychiatric and developmental conditions. To examine the accuracy of mental state inferences, a novel ToM task was developed, requiring inferences to be made about the mental states of 'Targets', prior participants who took part in a videoed mock interview. Participants also made estimates of the Targets' personality traits. These inferences were compared to ground-truth data, provided by the Targets, of their true traits and mental states. Results from 55 adult participants demonstrated that trait inferences were used to derive mental state inferences, and that the accuracy of trait estimates predicted the accuracy of mental state inferences. Moreover, the size and direction of the association between trait accuracy and mental state accuracy varied according to the trait-mental state combination. The accuracy of trait inferences was predicted by the accuracy of participants' understanding of trait covariation at the population level. Findings are in accordance with the Mind-space theory, that representation of the Target mind is used in the inference of their mental states.

Intrapersonal synchrony analysis reveals a weaker temporal coherence between gaze and gestures in adults with autism spectrum disorder

The temporal encoding of nonverbal signals within individuals, referred to as intrapersonal synchrony (IaPS), is an implicit process and essential feature of human communication. Based on existing evidence, IaPS is thought to be a marker of nonverbal behavior characteristics in autism spectrum disorders (ASD), but there is a lack of empirical evidence. The aim of this study was to quantify IaPS in adults during an experimentally controlled real-life interaction task. A sample of adults with a confirmed ASD diagnosis and a matched sample of typically-developed adults were tested (N = 48). Participants were required to indicate the appearance of a target invisible to their interaction partner nonverbally through gaze and pointing gestures. Special eye-tracking software allowed automated extraction of temporal delays between nonverbal signals and their intrapersonal variability with millisecond temporal resolution as indices for IaPS. Likelihood ratio tests of multilevel models showed enlarged delays between nonverbal signals in ASD. Larger delays were associated with greater intrapersonal variability in delays. The results provide a quantitative constraint on nonverbal temporality in typically-developed adults and suggest weaker temporal coherence between nonverbal signals in adults with ASD. The results provide a potential diagnostic marker and inspire predictive coding theories about the role of IaPS in interpersonal synchronization processes.

Furthering the language hypothesis of alexithymia: An integrated review and meta-analysis

Alexithymia, including the inability to identify and express one's own feelings, is a subclinical condition responsible for some of the socioemotional symptoms seen across a range of psychiatric conditions. The language hypothesis of alexithymia posits a language-mediated disruption in the development of discrete emotion concepts from ambiguous affective states, exacerbating the risk of developing alexithymia in language-impaired individuals. To provide a critical evaluation, a systematic review and meta-analysis of 29 empirical studies of language functioning in alexithymia was performed. A modest association was found between alexithymia and multi-domain language deficits (r = -0.14), including structural language, pragmatics, and propensity to use emotional language. A more theoretically-relevant subsample analysis comparing alexithymia levels in language-impaired and typical individuals revealed larger effects, but a limited number of studies adopted this approach. A synthesis of 11 emotional granularity studies also found an association between alexithymia and reduced emotional granularity (r = -0.10). Language impairments seem to increase the risk of alexithymia. Heterogeneous samples and methods suggest the need for studies with improved alexithymia assessments.

Psychoeducation Reduces Alexithymia and Modulates Anger Expression in a School Setting

Bullying and violence are relevant issues in school settings and negatively impact students’ well-being and mental health. Psychoeducation and anti-bullying programs may prevent violence among students by addressing emotional expression and regulation, alexithymia, and anger. We describe the impact of a psychoeducational intervention delivered to 90 male and 101 female school youths (N = 191), aged 12–14 years old, and aimed to improve their emotional recognition and regulation, as well as to reduce alexithymia in order to prevent aggression and bullying episodes. A psychological assessment has been performed before (T0) and after (T1) the intervention including levels of alexithymia, measured with the Toronto Alexithymia Scale-20 (TAS-20), the State-Trait Anger Expression Inventory (STAXI), Empathy Quotient (EQ), and the Emotion Regulation Questionnaire (ERQ). Females have shown higher levels of alexithymia at baseline whereas other characteristics (anger, empathy quotient and emotional regulation) did not differ among sex groups. The psychoeducational program significantly increased the empathy quotient (+10.2%), the emotional regulation reappraisal (+20.3%), and the assertive anger expression (+10.9%); alexithymia significantly decreased after the intervention in all the samples (−14.4%), above all among students scoring ≥61 at TAS-20 (−48.2%). Limitations include a small sample from a single school setting, the lack of a control group without psychoeducation, and an assessment based on self-reported measures. We may conclude that psychoeducation has significantly reduced levels of alexithymia and improved empathy and emotional regulation among adolescents.

Theory of Mind in migraine and medication-overuse headache: A cross-sectional study

Background

Theory of Mind (ToM) is the ability to predict and anticipate others' behaviors through the mental state attribution process. This study aims to investigate the ToM in patients with medication-overuse headache (MOH) and episodic migraine (EM) and to compare it with healthy controls (HC).

Methods

This study enrolled patients with MOH, patients with EM, and HC. ToM was assessed through the Theory of Mind Assessment Scale (ThOMAS), which includes four subscales: Scale A, I-Me, Scale B, Other-Self, Scale C, I-Other, and Scale D, Other-Me, through the Reading the Mind in the Eyes test (RMET), which measures complex emotion recognition, and through the Toronto Alexithymia Scale (TAS-20), which measures alexithymia. Concomitant psychiatric disturbances were evaluated through the Hamilton Anxiety Rating Scale, the Hamilton Depression Rating Scale, and the Dissociative Experiences Scale-II.

Results

The study involved 21 patients with EM, 22 patients with MOH, and 18 HC. In all the four subscales of the ThOMAS, there was a significant difference between HC, EM, and MOH patients: Scale A (p = 0.009), Scale B (p = 0.004), Scale C (p = 0.039), and Scale D (p = 0.008). In the RMET, MOH patients had worse performances than EM patients and HC (p = 0.039). MOH group exhibited higher levels of alexithymia when compared to the HC (p = 0.033) and higher levels of anxiety than HC (p = 0.001).

Conclusion

MOH patients showed a subtle psychopathological pattern characterized by impaired social adaptation.

Autism traits outweigh alexithymia traits in the explanation of mentalising performance in adults with autism but not in adults with rejected autism diagnosis

Background

Pronounced alexithymia traits have been found in autism spectrum disorder (ASD) and recent research has been carving out the impact alexithymia traits might have on mentalising deficits associated with ASD.

Method

In this cross-sectional study, a large representative referral population for diagnostic examination for possible ASD (n = 400) was screened for clinical alexithymia with a German version of the Reading the Mind in the Eyes test (RME). In contrast to previous attempts to carve out the impact of alexithymia traits on mentalising deficits though, we employed dominance analysis to account for the correlation between predictors. The relative relationship between alexithymia traits and autism traits with RME performance was investigated in the group of individuals with confirmed ASD diagnosis (N = 281) and compared to the clinical referral sample in which ASD was ruled out (N = 119).

Results

Dominance analysis revealed autism traits to be the strongest predictor for reduced mentalising skills in the ASD sample, whereas alexithymia contributed significantly less. In the sample of individuals with ruled out diagnosis, autism traits were the strongest predictor, but alexithymia traits were in sum equally associated to mentalising, with the External-Oriented Thinking subscale as an important predictor of this association.

Limitations

It needs to be considered that the cross-sectional study design does not allow for causal inference. Furthermore, mentalising is a highly facetted capacity and measurements need to reduce this complexity into simple quantities which limits the generalizability of results.

Discussion

While alexithymia traits should be considered for their mental health importance, they do not dominate the explanation of reduced mentalising skills in individuals with ASD, but they might do to a larger degree in individuals with ruled out ASD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13229-022-00510-9.