Interoception can be defined as the perception of physical sensations originating from within the body, along with the autonomic nervous system activity associated with emotions [1]. We experience sensations like hunger, thirst, pressure on our heads, and perhaps an inability of our feet to support us. The transformation of these unconscious sensations into conscious awareness, namely interoceptive awareness, occurs through processing these events and their elevation to conscious awareness [2]. Interoceptive awareness denotes the metacognitive connection between performance in interoceptive tasks and underlying beliefs [3]. Interoceptive awareness is a multifaceted construct; numerous self-report instruments have been created to evaluate it. The Multidimensional Interoceptive Awareness (MAIA-2) scale assesses interoceptive awareness across multiple dimensions from the first to the final phases of processing sensations [4]. Variations in these dimensions have been linked to numerous psychopathologies. In a study conducted by Dunne et al. [5] on patients who followed up with depressive disorder, they observed that trusting the body—one of the MAIA-2 subscales—was inversely related to the severity of depression. Lee et al. [6] also emphasized the relationship between interoceptive awareness (especially attention regulation) and clinical symptoms of anxiety and depression in their study.

Individuals regulate their emotions to adapt to physical and psychosocial conditions, enhancing their survival advantage [7]. Emotion regulation encompasses the activation of suitable emotional responses to internal bodily cues and external environmental stimuli, alongside implementing coping strategies to modulate the intensity of experienced emotions [8]. While short-term emotion dysregulation may confer survival advantages, it is linked to various health issues, including self-harming behaviors and the development of post-traumatic stress disorder [9,10].

Historically, numerous theories of emotion have emphasized the relationship between interoception and emotional experience. Emotion regulation involves a systematic relationship with the self, characterized by the interplay among the body, emotions, and cognitive processes. A coherent self-construct can be developed by accurately perceiving and evaluating cues associated with physiological responses, thereby linking the inner world with the outer world. Evidence indicates interoceptive awareness correlates with emotion regulation in healthy and clinical populations [11-13].

Alexithymia, characterized by difficulty expressing and identifying emotions, is associated with interoceptive awareness and emotion regulation [14]. In alignment with the hypothesis that emotion identification and expression represent sequential pathways in emotion processing, individuals with alexithymia exhibit difficulties with emotion regulation [15].

This study aimed to investigate the relationship between alexithymia, difficulties with emotion regulation, and interoceptive awareness among patients admitted to consultation liaison psychiatry, who frequently confront a mind-body dilemma with a negative focus on bodily sensations and unresolved medical symptoms. For this purpose, the hypotheses of our study are as follows: there is a negative relationship between interoceptive awareness and both difficulty in emotion regulation and alexithymia. Difficulty in emotion regulation mediates the relationship between interoceptive awareness and alexithymia.

The research involved 306 healthy participants. Of the participants, 61.1% were female, and 53.9% held university degrees. The average age of participants was 36.12±14.78 years. Additionally, 15.7% of participants reported having a physical illness. In that order, the predominant physical illnesses leading to referrals to the CLP unit included oncological, cardiological, dermatological, pain-related, gastroenterological, and endocrinological conditions. Thirty-six point nine percent of participants were identified as having a psychiatric illness. Among these, 42.4% were diagnosed with an acute stress response, 37.1% with an adjustment disorder, 6.0% with a depressive disorder, and 9.0% with an anxiety disorder; the remaining cases were classified as somatoform disorders. Table 1 presents the descriptive statistics for the participants.

Participants were categorized based on the presence or absence of alexithymic features, determined by their TAS-20 scores, with a cut-off value of 59 or higher. The differences in MAIA-2 subscale scores between the two groups were analyzed [23]. Individuals with higher alexithymic features were found to have lower interoceptive awareness scores (t=-7.588, p<0.001) and more emotional regulation difficulties (t=10.123, p<0.001). However, no significant difference was observed between individuals with higher and lower alexithymia on the MAIA-2 not worrying and not distracting subscales. The results are shown in Table 2.

Pearson correlation analyses were conducted between the participants’ MAIA-2 subscales, DERS-16, and TAS-20 scores. The study found a negative relationship between alexithymia and the general interoceptive awareness factor (r=-0.493, p<0.001) and a significant negative relationship between alexithymia and difficulty in emotion regulation (r=0.668, p<0.001). The MAIA-2 subscale scores of not worrying showed a low correlation with alexithymia, while not distracting showed no significant correlation. Table 3 displays the relationship between the participants’ scale scores.

Mediation analysis (Model 4) assessed interactions between the MAIA-2 general factor, alexithymia, and Difficulties in Emotion Regulation. As seen in Table 4 and Figure 1, interoceptive awareness significantly predicted alexithymia (β=-0.516, t=-8.775, p<0.001), and the direct effect of interoceptive awareness on alexithymia remained statistically significant even after considering the effect of the mediator variable (β=-0.203; t=-3.486; 95% CI, -1.136 to -0.315; p=0.001). The paths from interoceptive awareness to difficulties in emotion regulation and from difficulties in emotion regulation to alexithymia showed significant relationships, with difficulties in emotion regulation mediating the relationship between alexithymia and interoceptive awareness (β=-0.313; 95% CI, -0.405, to -0.227; SE=0.045) (Table 4 and Figure 1). Statistical analysis revealed a significant mediation effect of emotion regulation difficulties in the relationship between interoceptive awareness and alexithymia (Figure 1), with the model accounting for 49.9% of the variance in alexithymia. The effect size, calculated as the proportion mediated, is approximately 0.61. This means that around 61% of the effect of interoceptive awareness on alexithymia is mediated through difficulties in emotion regulation, indicating a substantial mediation effect.

This study investigates the relationship among interoceptive awareness, difficulties in emotion regulation, and alexithymia within a CLP sample. In our study, we demonstrated that interoceptive awareness is negatively associated with both difficulty in emotion regulation and alexithymia. Additionally, consistent with our hypothesis, we found that difficulties in emotion regulation mediate the relationship between interoceptive awareness and alexithymia.

Alexithymia serves as an indicator of atypical interoception [24]. The relationship between interoception and alexithymia has been highlighted in early and late alexithymia formulations but has yielded relatively mixed results. This confusion stems from using interchangeable terms and differences in measurement methods [25]. The study’s findings indicate that MAIA-2 subscales, except the “not worrying” and “not distracting” subscales, were lower in individuals exhibiting high levels of alexithymia. Ferentzi et al. [18] proposed that “not worrying” and “not distracting” are associated with an inappropriate anxiety-focused internal attention style rather than a stable interoceptive sensitivity, indicating a potential link to trait anxiety. Todd et al. [26] demonstrated that the MAIA-2 is the most central scale for assessing interoceptive sensitivity, defined as the tendency to notice bodily changes in response to events that may alter a person’s physiological state. However, the “not worrying” and “not distracting” subscales do not apply in this context. The correlation analyses, including alexithymia, revealed no significant link with the “not worrying” subscale; however, a substantial yet minor negative correlation was identified with the “not distracting” subscale. The “attentional regulation” and “trusting” subscales identified the most significant relationships with alexithymia. In other words, individuals with alexithymia pay less attention to congruent bodily experiences and do not consider these sensations trustworthy. Analysis of the pertinent literature indicates that persons with alexithymia achieve standard scores on interoceptive accuracy assessments that objectively evaluate interoception, although they exhibit discrepancies in subjective report questionnaires [27]. This situation can be interpreted as the deterioration of interoceptive processing in the later stages of alexithymia formation. Consistent with our findings, the absence of a significant difference in the “not worrying” and “not distracting” subscales among alexithymic individuals might be interpreted as these two subscales evaluating the early to middle phases of automatic attention and emotional processing [4,28].

The multidimensional structure of the MAIA-2 scale reveals that the scale’s total score cannot be used for an evaluation purpose [28]. A mediation analysis was conducted by creating a general interoceptive awareness factor in accordance with previous studies [29]. There was a significant negative relationship between general interoceptive awareness, alexithymia, and difficulty in emotion regulation. The significance remained when emotion regulation difficulty was included in the model. Awareness of internal signals from different bodily regions is crucial for sustaining homeostasis and regulating behaviors that provide equilibrium between the internal and external worlds [1]. As early theories of emotion underlined, according to Damasio [30], emotional expressions paired with physiological responses are somatic markers that guide behavior and cognition. In accordance with Damasio, Füstös et al. [31] have emphasized the significance of meta-representations of bodily states in the development and regulation of emotions. Pistoia et al. [32] found that individuals with spinal cord injuries have difficulty regulating their emotional responses while assessing emotionally charged scenes, thereby underscoring the significance of sensory feedback in emotional experience. Accordingly, reduced scores on the interoceptive awareness subscales were observed in individuals with medically unexplained symptoms, suggesting that therapies focused on bodily awareness could enhance interoceptive capacities in this patient population [4]. Additionally, Schaefer et al. [33] found that interoceptive interventions resulted in lower health anxiety in patients with somatoform disorders. According to the findings of our study, the relationship between interoceptive awareness and difficulty in emotion regulation is consistent with previous studies. Desdentado et al. [34] demonstrated that the interpretation of sensations (non-judgmental and accepting) correlates with the ability to regulate emotional abilities rather than the level of intensity of their perception. Schuette et al. [35] demonstrated a positive relationship between interoceptive sensitivity and emotion identification and regulation using the MAIA-2 in a nonclinical population. Zamariola et al. [11] found that individuals with diminished interoceptive capacities encountered increased challenges in mitigating the emotional consequences of negative experiences. Jakubczyk et al. [13] have paired the ability to recognize and be aware of somatic sensations with the capacity to accept negative emotional states, an adaptive emotion regulation strategy, in individuals with alcohol use disorder. Nevertheless, the literature on the topic remains ambiguous. In a laboratory investigation, people with elevated self-reported interoceptive awareness exhibited more negative affect following a negative feedback manipulation [36].

Although theories suggesting a positive relationship between interoceptive abilities and the ability to recognize and regulate emotions have reported negative relationships between interoception and alexithymia [37,38], recent studies have failed to replicate this relationship [39]. A recent meta-analysis revealed no significant correlation between interoception’s self-reported subjective aspect, interoceptive sensitivity, and alexithymia [25]. On the other hand, in line with the somatosensory amplification hypothesis, alexithymic individuals may be more sensitive to the perception of bodily sensations [40]. Palser et al. [41] noted that anxious individuals randomly experience physical sensations that are typically subthreshold and associate them with negative consequences via alexithymia. The discrepancy between studies on interoceptive awareness and alexithymia may be because the MAIA-2 and Body Perception Questionnaire, the predominant tools for evaluating interoceptive awareness, distinctly assess this construct’s adaptive and maladaptive dimensions. An attentive and receptive approach to body sensations enhances emotion regulation, but an exclusive emphasis on somatic symptoms may lead to strategies like rumination and somatization, which make successful emotion regulation difficult.

One of the key findings of our study is the relationship between difficulties in emotion regulation and alexithymia. Our results indicate that difficulty in emotion regulation mediates the relationship between interoceptive awareness and alexithymia. In contrast, previous studies have highlighted the potential mediating role of alexithymia in the relationship between interoceptive awareness and difficulties in emotion regulation [29,42]. From the perspective of the attention-appraisal model of alexithymia, the processing of emotional information can be considered a precursor to emotion regulation [15,43]. However, we found it valuable to highlight the other side of the coin in our study. The emotional process functions as a continuously evolving mechanism, dynamically adapting to internal and external feedback sources within a system of circular causality [44]. In this context, the temporal boundary between emotion generation and regulation may not always be clearly defined [45]. This has been supported by neuroimaging studies conducted by Burklund et al. [46], which revealed that emotion labeling and reappraisal share common neural mechanisms. However, given the cross-sectional design of our study, establishing causal relationships remains challenging, and longitudinal studies are needed to provide further clarity.

Our research elucidates the relationship among interoceptive awareness, challenges in emotion regulation, and alexithymia within a CLP population. Clinicians in the consultation-liaison domain frequently engage with patients who exhibit recurrent hospitalizations, unexplained medical symptoms, and a disconnection between their symptoms and the emotions they elicit. Within this group, Mindful Awareness in Body-Oriented Therapy activities may facilitate the restoration of the disrupted mind-body connection by instructing individuals to focus on their body language [47]. Consequently, maladaptive stress reactions may be re-regulated, facilitating healthy responses and emotional regulation in individuals.

Our study has certain limitations. Initially, our sample comprised patients seeking consultation-liaison psychiatry, and our findings cannot be extrapolated to clinical populations. Second, alexithymia and emotion regulation difficulties were assessed using self-report techniques. This could result in skewed replies and distorted outcomes. Third, this study assessed interoceptive awareness from multiple dimensions but did not consider performance-based interoceptive factors. The cross-sectional form of our investigation precludes the determination of causality and temporal correlations.

In conclusion, there are various changes in most stages of interoceptive awareness in individuals with higher alexithymia. Difficulties in emotion regulation accompany some relationships between altered interoceptive awareness and alexithymia. Interventions such as mindfulness-based therapies, yoga, and physical activity that increase interoceptive awareness may reduce alexithymia or emotion regulation difficulty.