Understanding contributors to emotional distress is a key component of our understanding of mental health symptoms and disorders, such as anxiety and depression. One key characteristic that may be associated with distress is alexithymia, defined as difficulty understanding and verbalizing one's own emotions (Taylor, 1984). Alexithymia is seen in approximately 10 % of the general population (Tolmunen et al., 2011). Identified in the 1970's, alexithymia has recently been a focus of research given its prevalence among those with mental health disorders, with rates as high as 32.0 % in adults with depression (Honkalampi et al., 2000) and 76.5 % in adolescents with depression (Wang et al., 2021), 79.1 % in those with anxiety (Karukivi et al., 2010), and 30–50 % in those with substance use disorders (Morie et al., 2016; Haviland et al., 1994). Given these findings, alexithymia is of significant clinical interest. Thus, the goal of this work was to examine the associations between facets of alexithymia, emotion regulation, and distress in a large sample of individuals recruited from an online crowdsourcing platform.

As alexithymia is so common among those with depression and anxiety, it may serve as a transdiagnostic vulnerability factor for mental illness (Leweke et al., 2012) or for increased distress when an individual experiences trauma or a large-scale stressor, such as the COVID-19 pandemic (Wang et al., 2021; La Rosa et al., 2022). Key features of alexithymia are poor emotion identification and decreased ability to communicate emotions to others, such as peers or therapists potentially contributing to increased distress. This interpretation of alexithymia as a potent construct that may worsen distress is supported by findings in both general and clinical populations that indicate alexithymia is associated with suicidality (Davey et al., 2018; Hemming et al., 2019), poorer interpersonal relationships (Vanheule et al., 2010; Talebi, 2014), and poorer quality of life (Shim et al., 2018; Vieira et al., 2013). Clearly, alexithymia is a powerful transdiagnostic risk factor, but mechanisms of action remain understudied. Examining the associations between different components of the alexithymic phenotype (e.g., identifying and verbalizing) and different types of distress (e.g., depression, anxiety, and stress) may help to clarify its potential role as a vulnerability factor for clinically significant symptoms. Furthermore, exploring potential mediators of these associations, such as emotion regulation, may help to delineate potential mechanisms.

Emotion regulation refers to the ability to manage one's emotional state and how one responds to their emotions (Gross, 2015). Commonly used measures of emotion regulation include the assessment of suppression (a maladaptive response that involves ignoring or suppressing emotions) and reappraisal (the beneficial ability to re-frame one's thoughts about what one is feeling) (Goldin et al., 2008), and are commonly measured with the Emotion Regulation Questionnaire (ERQ), (Gross and John, 2003a) which was used here. Given the recent model from our laboratory that states that an individual must be able to identify the emotion they are feeling before they can properly make use of these emotion regulation strategies (Morie et al., 2022), the presence of alexithymia would logically impair emotion regulation. The literature on alexithymia so far supports this assertion, with strong associations seen between alexithymia and measures of emotion regulation (Preece et al., 2022). Further, reappraisal is commonly negatively correlated with alexithymia, while suppression is commonly positively associated with alexithymia (Laloyaux et al., 2015), and alexithymia is associated with generally maladaptive emotion regulation strategies (Preece et al., 2023).

A recent model of emotional identification by our laboratory illustrates the importance of different factors associated with intact emotional identification, and different patterns of deficits may contribute to different presentations of mental health difficulties (Morie et al., 2022). It is possible that different contributions of different alexithymia factors or certain factors over others may play an important role in different types of distress, even among individuals in the general population. This is supported by findings from Alkan et al. (Alkan et al., 2014), which suggest that different combinations of alexithymia factors are associated with higher or lower distress in non-clinical adults. Other work that used cluster analysis of alexithymia has indicated that different combinations of individual factors of alexithymia are associated with different patterns of emotion regulation and different levels of depression and anxiety among the general population (Chen et al., 2011). Given significant mental health and physical health co-morbidities associated with distress (Arvidsdotter et al., 2016), it is therefore essential to further examine how different factors of alexithymia may contribute to different kinds of distress, including depression, anxiety, and stress, in the general population.

Alexithymia is typically measured with either the 20-item Toronto Alexithymia Scale (TAS-20; (Bagby et al., 1994)) or the 40-item Bermond Vost Alexithymia Questionnaire (BVAQ; (Sauvage and Loas, 2006)). The BVAQ was used for this study, as its constituent factors were identified as being preferable to the TAS-20 with regard to being separable from the general concept of distress (Preece et al., 2020a). These questionnaires can be divided into individual factors, splitting the concept into three (TAS-20) or five (BVAQ) major factors. Common to both is identifying and verbalizing emotion, which respectively address the ability to identify what one is feeling and verbally describe that feeling. The TAS-20 also examines externalization, while the BVAQ splits alexithymia further into subscales describing analyzing emotion (examining explanations for experienced emotions) emotionalizing (intensity of experienced emotion) and fantasizing (ability to fantasize about virtual events). While comparatively little literature has examined these factors independently, doing so may offer additional insight into how alexithymia contributes to distress. The Depression Anxiety Stress scales (DASS), also used here, is a reliable trans-diagnostic measure of distress severity in clinical and non-clinical populations (Gloster et al., 2008; Crawford and Henry, 2003; Brown et al., 1997a; Lovibond and Lovibond, 1995a).

The goals of this project were twofold. The first goal was to determine the extent of the association between alexithymia and distress in the general population, with a focus on the specific contributions of each factor of alexithymia and the potential mediation through reappraisal and suppression. The second goal was to determine if combinations of specific factors of alexithymia were directly associated with specific aspects of distress, including depression, anxiety, and stress. Findings may help to further define the trans-diagnostic role of alexithymia and its constituent factors on distress in healthy and clinical populations.

To achieve these goals, a path analysis was constructed to determine the extent to which our variables of interest (i.e., the five alexithymia factors and the two emotion regulation strategies) explained variance in reported depression, anxiety, and stress and examined the contributions of each individual factor through emotion regulation strategies. There were two major hypotheses. The first was that increased alexithymia would be associated with poorer emotion regulation strategies, with decreased reappraisal, increased suppression, and thus increased distress, with a large portion of the variance in distress explained by alexithymia and its associations with emotion regulation strategies. The second was that different combinations of alexithymia factors would be associated with depression, anxiety, and stress, suggesting that specific factors of alexithymia may be associated with different types of distress.