Is alexithymia characterised by impaired interoception? Further evidence, the importance of control variables, and the problems with the Heartbeat Counting Task

Major Depressive Disorder Is Associated with Impaired Interoceptive Accuracy: A Systematic Review

Interoception is the sense of the physiological condition of the entire body. Impaired interoception has been associated with aberrant activity of the insula in major depressive disorder (MDD) during heartbeat perception tasks. Despite clinical relevance, studies investigating interoceptive impairments in MDD have never been reviewed systematically according to the guidelines of the PRISMA protocol, and therefore we collated studies that assessed accuracy in detecting heartbeat sensations (interoceptive accuracy, IAc) in MDD (databases: PubMed/Medline, PsycINFO, and PsycARTICLES). Out of 389 records, six studies met the inclusion criteria. The main findings suggest that (i) moderately depressed samples exhibit the largest interoceptive deficits as compared with healthy adults. (ii) difficulties in decision making and low affect intensity are correlated with low IAc, and (iii) IAc seems to normalize in severely depressed subjects. These associations may be confounded by sex, anxiety or panic disorder, and intake of selective serotonin reuptake inhibitors. Our findings have implications for the development of interoceptive treatments that might relieve MDD-related symptoms or prevent relapse in recurrent depression by targeting the interoceptive nervous system.

The Role of Language in Alexithymia: Moving Towards a Multiroute Model of Alexithymia

Alexithymia is characterized by difficulty identifying and describing one’s own emotion. Identifying and describing one’s emotion involves several cognitive processes, so alexithymia may result from a number of impairments. Here we propose the alexithymia language hypothesis—the hypothesis that language impairment can give rise to alexithymia—and critically review relevant evidence from healthy populations, developmental disorders, adult-onset illness, and acquired brain injury. We conclude that the available evidence is supportive of the alexithymia–language hypothesis, and therefore that language impairment may represent one of multiple routes to alexithymia. Where evidence is lacking, we outline which approaches will be useful in testing this hypothesis.

Interoceptive Awareness, Alexithymia, and Sexual Function

Research in women suggests a relation between sexual difficulties and lower interoceptive awareness, the conscious perception of internal bodily states. Lower interoceptive awareness is theoretically linked to greater alexithymia, which has been related to sexual dysfunctions. Hence, we examined the relations of interoceptive awareness and alexithymia with several dimensions of sexual functioning in a nonclinical sample of both sexes. Methods: Three hundred forty Portuguese (228 women, 112 men) completed the Toronto Alexithymia Scale (TAS-20) and the Multidimensional Assessment of Interoceptive Awareness (MAIA). Women additionally completed the Female Sexual Function Index (FSFI) and the Female Sexual Distress Scale-Revised (FSDS-R). Men additionally completed the International Index of Erectile Function (IIEF) and one question on difficulties delaying ejaculation. Greater alexithymia correlated with lesser interoceptive awareness. For women, greater alexithymia and lesser interoceptive awareness correlated with lesser arousal, lesser lubrication, more orgasm difficulties, more dissatisfaction, more pain, and more sexual distress. Higher female desire correlated with greater interoceptive awareness, but was unrelated to alexithymia. In men, lesser interoceptive awareness correlated with more difficulties delaying ejaculation, and greater alexithymia correlated with more erectile difficulties. The present investigation corroborates that awareness of emotions and internal bodily states is important for sexual functioning.

Relationship between interoception and emotion regulation: New evidence from mixed methods

BACKGROUND

Interoception is the ability to perceive one's inner bodily feelings and is thought to be associated with the capacity of recognising and experiencing emotions. Previous research on interoception and emotion regulation has presented limitations arising from the low reliability of the interoceptive measurement and provided inconsistent results. The current study used a mixed method approach to investigate this relationship from the individuals' perspective.

METHODS

In the first phase (quantitative), questionnaires assessing interoceptive sensibility, the subjective, self-reported ability to perceive internal states, were administered to 100 healthy participants. In the second phase (qualitative), individual semi-structured interviews were conducted with nine participants. The interviews were analysed using the Interpretative Phenomenological Analysis. Three main dimensions were explored with open questions: 1) Perception of internal bodily states; 2) Emotion regulation; 3) Potential relationship between bodily states perception and emotion recognition and regulation.

RESULTS

Findings revealed that people with low interoceptive abilities show more difficulties in verbalizing their feelings and in decreasing the impact of emotions generated by negative experiences in daily life LIMITATIONS: The generalization of the results is limited by the specific age and gender of the recruited sample.

CONCLUSIONS

Responses of the participants supported recent evidence regarding the lack of reliability of the heartbeat counting task as a measure of interoceptive accuracy, however interviews sustained the importance of recognising the bodily states in order to be able to understand and regulate emotions.

Alexithymic traits can explain the association between puberty and symptoms of depression and anxiety in adolescent females

Symptoms of internalizing disorders such as depression and anxiety increase in adolescence, especially in females. However, gender differences in depression and anxiety symptoms emerge only after puberty onset. Levels of alexithymia, characterized by difficulties identifying and describing one's emotions, are elevated in depression and anxiety, and fluctuate across adolescence in a gender-specific manner. This study investigated changes in alexithymia across adolescence, and explored the potential role of alexithymia in the development of depression and anxiety, separately for females and males. Accordingly, 140 adolescents aged 11 to 21 years (77 female) completed self-report measures of alexithymia, depression and anxiety, and pubertal development. For females alone, pubertal maturation was associated with alexithymic traits (specifically difficulties identifying and describing feelings), as well as symptoms of depression and anxiety. After accounting for alexithymia, the relationship between puberty and depression and anxiety was absent or reduced in females. Thus, alexithymic traits may have differential consequences for males and females, and possibly contribute towards increased depression and anxiety symptoms in females during adolescence. We propose that developmental changes in alexithymia should be considered when studying the onset and development of internalizing psychological disorders during adolescence.

Dimensions of interoception predict premonitory urges and tic severity in Tourette syndrome

Interoceptive processes in Tourette syndrome may foster the premonitory urges that commonly precede tics. Twenty-one adults with TS and 22 controls completed heartbeat tracking and discrimination tasks. Three dimensions of interoception were examined: objective accuracy, metacognitive awareness, and subjective (self-report) sensibility. Trait interoceptive prediction error was calculated as the discrepancy between accuracy and sensibility. Participants with TS had numerically lower interoceptive accuracy on the heartbeat tracking task, and increased self-reported interoceptive sensibility. While these group differences were not significant, the discrepancy between lower interoceptive accuracy and heightened sensibility, i.e. the trait interoceptive prediction error, was significantly greater in TS compared to controls. This suggests a heightened higher-order sensitivity to bodily sensations in TS, relative to a noisier perceptual representation of afferent bodily signals. Moreover, interoceptive sensibility predicted the severity of premonitory sensations and tics. This suggests interventions that work to align dimensions of interoceptive experience in TS hold therapeutic potential.

Childhood Trauma Affects Stress-Related Interoceptive Accuracy

Early life adversity (ELA) may cause permanent disturbances in brain-body signaling. These disturbances are thought to contribute to physical symptoms and emotional dysregulation in adulthood. The current study investigated the effects of childhood trauma on young adults' interoceptive accuracy as an indicator of brain-body communication that may be dysregulated by ELA. Sixty-six participants completed an online questionnaire followed by a laboratory session including the socially evaluated cold pressor stress test during which ECG, salivary cortisol, and interoceptive accuracy were assessed. Childhood trauma was negatively related to interoceptive accuracy (IAc) after the stressor. This stress effect could not be observed for heart rate and cortisol, which were unrelated to IAc. Participants reporting higher baseline unpleasantness exhibited lower IAc after the stressor, while increases in unpleasantness due to the stressor were associated with higher IAc. Unpleasantness at baseline mediated the effect of childhood trauma on IAc after the stressor.

Alexithymia and the Reduced Ability to Represent the Value of Aversively Motivated Actions

Alexithymia is a subclinical trait defined by difficulties in identifying and describing feelings and a cognitive style avoidant of introspection. Extensive literature shows that alexithymia is characterized by multifaceted impairments in processing emotional stimuli. Nevertheless, the mechanisms that may account for such impairments remain elusive. Here, we hypothesize that alexithymia may be understood as impairment in learning the emotional value of one’s own actions and test this comparing performance of participants with high (HA) and low (LA) levels of alexithymia on a probabilistic selection task. Results show that, compared to LA, HA need more time to learn the value of individual stimuli and associated actions as difference in reinforcement rate between stimuli decreases. In addition, HA appear less able to generalize the value of previously learned actions that lead to a negative outcome, to make adaptive choices in a new context, requiring more time to avoid the most negative stimulus between two negative stimuli. Together, the results indicate that individuals with alexithymia show impaired learning of the value of aversively motivated actions. We argue that this impairment may hinder the construction of internal representations of emotional stimuli and actions and represent a mechanism that may account for the difficulties of alexithymia in processing emotional stimuli.

Alexithymia mediates the relationship between interoceptive sensibility and anxiety

A number of empirical and theoretical reports link altered interoceptive processing to anxiety. However, the mechanistic understanding of the relationship between the two remains poor. We propose that a heightened sensibility for interoceptive signals, combined with a difficulty in attributing these sensations to emotions, increases an individual’s vulnerability to anxiety. In order to investigate this, a large sample of general population adults were recruited and completed self-report measures of interoceptive sensibility, trait anxiety and alexithymia. Results confirmed that the positive association between interoceptive sensibility and trait anxiety was partially mediated by alexithymia, such that those most at risk for clinically significant levels of trait anxiety have both significantly higher levels of interoceptive sensibility and alexithymia. A subsequent factor analysis confirmed the independence of the three measures. Altered interoceptive processing in combination with alexithymia, increased the risk for anxiety above and beyond altered interoceptive processing alone. We suggest that a heightened sensibility for interoceptive signals, combined with a difficulty in attributing these sensations to emotions, leaves these sensations vulnerable to catastrophizing interpretation. Interventions that target the attribution of bodily sensations may prove valuable in reducing anxiety.

Characteristics of brain functional and structural connectivity in alexithymic students

BACKGROUND

Alexithymia is a multifaceted personality trait and a risk factor for several mental and physical diseases.

METHODS

In this study, 21 alexithymic students and 21 nonalexithymic students were recruited from the local university and assigned to the alexithymic group and the control group, respectively. Then, the functional connectivity and the structural connectivity among the brain regions of the students were investigated using resting-state functional magnetic resonance imaging (rsfMRI), function connection (FC) analysis, and diffusion tensor imaging (DTI).

RESULTS

The rsfMRI results revealed 14 brain regions showing significant differences in the amplitude of low-frequency fluctuations between the two groups. Comparative analysis of the FC and DTI data in these brain regions between the two groups identified altered levels of functional and structural connectivity between the following four pairs of regions in the alexithymic subjects: the right inferior temporal gyrus and the central posterior gyrus, the left temporal gyrus and the insula, and the bilateral superior frontal gyrus and the anterior cingulate gyrus.

CONCLUSION

Compared with single MRI analysis, the multiple MRI analysis identified more precisely the brain regions that could play a key role in the development of alexithymia.