Emotion recognition deficits in eating disorders are explained by co-occurring alexithymia

Understanding self and others: from origins to disorders

In order to interpret and engage with the social world, individuals must understand how they relate to others. Self-other understanding forms the backbone of social cognition and is a central concept explored by research into basic processes such as action perception and empathy, as well as research on more sophisticated social behaviours such as cooperation and intergroup interaction. This theme issue integrates the latest research into self-other understanding from evolutionary biology, anthropology, psychology, neuroscience and psychiatry. By gathering perspectives from a diverse range of disciplines, the contributions showcase ways in which research in these areas both informs and is informed by approaches spanning the biological and social sciences, thus deepening our understanding of how we relate to others in a social world.

The influence of variations in eating disorder-related symptoms on processing of emotional faces in a non-clinical female sample: An eye-tracking study

This study aimed to: (i) determine if the attention bias towards angry faces reported in eating disorders generalises to a non-clinical sample varying in eating disorder-related symptoms; (ii) examine if the bias occurs during initial orientation or later strategic processing; and (iii) confirm previous findings of impaired facial emotion recognition in non-clinical disordered eating. Fifty-two females viewed a series of face-pairs (happy or angry paired with neutral) whilst their attentional deployment was continuously monitored using an eye-tracker. They subsequently identified the emotion portrayed in a separate series of faces. The highest (n=18) and lowest scorers (n=17) on the Eating Disorders Inventory (EDI) were compared on the attention and facial emotion recognition tasks. Those with relatively high scores exhibited impaired facial emotion recognition, confirming previous findings in similar non-clinical samples. They also displayed biased attention away from emotional faces during later strategic processing, which is consistent with previously observed impairments in clinical samples. These differences were related to drive-for-thinness. Although we found no evidence of a bias towards angry faces, it is plausible that the observed impairments in emotion recognition and avoidance of emotional faces could disrupt social functioning and act as a risk factor for the development of eating disorders.

Alexithymia is associated with attenuated automatic brain response to facial emotion in clinical depression

BACKGROUND

Alexithymia is a clinically relevant personality trait related to difficulties in recognizing and describing emotions. Previous studies examining the neural correlates of alexithymia have shown mainly decreased response of several brain areas during emotion processing in healthy samples and patients suffering from autism or post-traumatic stress disorder. In the present study, we examined the effect of alexithymia on automatic brain reactivity to negative and positive facial expressions in clinical depression.

METHODS

Brain activation in response to sad, happy, neutral, and no facial expression (presented for 33 ms and masked by neutral faces) was measured by functional magnetic resonance imaging at 3 T in 26 alexithymic and 26 non-alexithymic patients with major depression.

RESULTS

Alexithymic patients manifested less activation in response to masked sad and happy (compared to neutral) faces in right frontal regions and right caudate nuclei than non-alexithymic patients.

CONCLUSIONS

Our neuroimaging study provides evidence that the personality trait alexithymia has a modulating effect on automatic emotion processing in clinical depression. Our findings support the idea that alexithymia could be associated with functional deficits of the right hemisphere. Future research on the neural substrates of emotion processing in depression should assess and control alexithymia in their analyses.

Acquired alexithymia following damage to the anterior insula

Alexithymia is a subclinical condition characterized by impaired awareness of one's emotional states, which has profound effects on mental health and social interaction. Despite the clinical significance of this condition, the neurocognitive impairment(s) that lead to alexithymia remain unclear. Recent theoretical models suggest that impaired anterior insula (AI) functioning might be involved in alexithymia, but conclusive evidence for this hypothesis is lacking. We measured alexithymia levels in a large sample of brain-injured patients (N=129) and non-brain-injured control participants (N=33), to determine whether alexithymia can be acquired after pronounced damage to the AI. Alexithymia levels were first analysed as a function of group, with patients separated into four groups based on AI damage: patients with >15% damage to AI, patients with <15% damage to AI, patients with no damage to AI, and healthy controls. An ANOVA revealed that alexithymia levels varied across groups (p=0.009), with >15% AI damage causing higher alexithymia relative to all other groups (all p<0.01). Next, a multiple linear regression model was fit with the degree of damage to AI, the degree of damage to a related region (the anterior cingulate cortex, ACC), and the degree of damage to the whole brain as predictor variables, and alexithymia as the dependent variable. Critically, increased AI damage predicted increased alexithymia after controlling for the other two regressors (ACC damage; total lesion volume). Collectively, our results suggest that pronounced AI damage causes increased levels of alexithymia, providing critical evidence that this region supports emotional awareness.

Emotion Recognition in Blended Facial Expressions in Women with Anorexia Nervosa

People with anorexia nervosa (AN) have difficulties in the social domain, and problems in the ability to recognise emotions in people's faces may contribute to these difficulties. This study aimed to investigate emotion recognition in women with AN and healthy controls (HC), using pictures of faces portraying blended emotions at different levels of ambiguity, which resemble real-life expressions more closely than prototypical expressions used in past studies. Seventy-seven participants (35 AN; 42 HC) completed the emotion recognition task. Results indicated that participants with AN were less accurate than HC recognising expressions of disgust, when shown less ambiguously. There were no differences in the recognition of other emotions. Participants with AN also showed response bias towards anger. These findings suggest a generally preserved ability to recognise emotions in women with AN, with the exception of disgust recognition. They also support previous findings of bias towards anger in AN patients.

Analysis of functional variants reveals new candidate genes associated with alexithymia

In this study we explored the possible association between 36,915 functional variants and alexithymia, a personality trait characterized by the inability to identify and describe emotions and feelings. From our analysis, variants in the genes ABCB4, TP53AIP1, ARHGAP32 and TMEM88B were identified linked to the alexithymia phenotype.

Atypical trait inferences from facial cues in alexithymia

It is often difficult to distinguish strangers’ permanent facial shapes from their transient facial expressions, for example, whether they are scowling or have narrow-set eyes. Overinterpretation of ambiguous cues may contribute to the rapid character judgments we make about others. Someone with narrow eyes might be judged untrustworthy, because of strong associations between facial anger and threat. To test this hypothesis, we investigated the trait judgments made by individuals with severe alexithymia, associated with impaired recognition of facial emotion. Consistent with the hypothesis, alexithymic participants demonstrated reduced interrater consistency when judging the character traits of unfamiliar faces, and the presence of subtle emotions. Nevertheless, where alexithymics perceived, or misperceived, emotion cues, the character traits inferred thereafter were broadly typical. The finding that individuals with developmental deficits of emotion recognition exhibit atypical attribution of character traits, confirms the hypothesis that emotion-recognition mechanisms play a causal role in character judgments.