Alexithymia, dissociation and emotional regulation in eating disorders: Evidence of improvement through specialized inpatient treatment

Abstract The research into emotional regulation in eating disorders (EDs) has shown specific impairments and maladaptive coping strategies in patients, and there is an increasing interest in the role of the emotional domain in the treatment outcome. This study aims to evaluate the effect of a specialized inpatient treatment characterized by both an intensive and comprehensive standardized multidisciplinary programme based on cognitive–behavioural therapy and a flexible and personalized component implemented by third‐wave interventions. A cohort of 67 female ED patients (anorexia nervosa = 28, bulimia nervosa = 28 and binge eating disorder = 11) underwent an evaluation of emotional regulation difficulties, alexithymia and dissociative symptomatology at admission to a specialized ED ward. The psychological modifications were subsequently re‐evaluated upon discharge, after an inpatients treatment of 60 days, examining specific changes in the specific psychopathology. A significant improvement after specialized ED treatment was shown in alexithymia, emotional regulation difficulties and dissociation symptoms, with higher effect sizes in patients with higher alexithymia scores. As regards the specific effect of the psychological improvement, changes into alexithymia scores have shown specific correlations with ED psychopathology (p < 0.010) and with difficulties in emotional regulation (p < 0.010) in patients with higher alexithymia levels at admission. Emotional regulation and dissociation should therefore be evaluated in ED patients and may be improved with specific therapeutic approaches, while alexithymia remains a clinical trait, even with a significant reduction.

eating habits (C.G. Fairburn et al., 2003;M. Solmi, Gallicchio, et al., 2018), researchers identified a more comprehensive psychopathological core characterized by affective comorbidities, interpersonal and interoceptive difficulties, ineffectiveness and a drive for thinness (M. . Based on the transdiagnostic perspective, various treatment protocols focusing on dysfunctional schemas and behaviours have been proposed (C.G. Fairburn et al., 2003;Murray et al., 2019), but treatment outcomes remain unclear (J. Linardon, Wade, et al., 2017). Dissociation, alexithymia and emotional dysregulation have been identified as relevant comorbidities that could interfere with eating-disordered patients' improvement and recovery, but in the current literature, there is no consensus as for effective ways to reduce these symptoms (Fernández-Aranda et al., 2008;Gramaglia et al., 2020;Thompson-Brenner et al., 2019;Westwood et al., 2017). Indeed, even though outpatient psychotherapy is recommended as first-line treatment, the recovery rates are still inadequate, and residential programmes are needed for patients who have severe symptoms or comorbidities that cannot be treated through less intensive approaches; however, there is not much data available on the benefits of inpatient treatment (Thompson-Brenner et al., 2019).
Emotional regulation, which is defined as "the ability to identify and modulate the experience and expression of emotions," has recently been proposed as a potential transdiagnostic therapeutic target for ED patients (Mallorquí-Bagué et al., 2018) due to the increasing evidence that ED patients have difficulty identifying and modulating emotions. Patients present dysfunctional, maladaptive psychological features such as suppression, rumination or emotional avoidance to manage emotions (Aloi et al., 2017;Mallorquí-Bagué et al., 2018;Meneguzzo et al., 2020), and the eating disorder symptoms were used as a coping strategy for unbearable emotions (Moulton et al., 2015;K. Trottier et al., 2016;K. Trottier & MacDonald, 2017). Indeed, early data suggest there may be benefits in treating EDs by implementing an emotional regulation protocol (Thompson-Brenner et al., 2019); however, the results are still preliminary and show conflicting evidence (Caslini et al., 2015).
The inability of ED patients to recognize and report emotions has been correlated with alexithymia and dissociation, two dysfunctional psychological features that patients use to cope with intolerable or frightening emotions: unrecognizable feelings, or disintegrate consciousness, memory and identity (Grabe et al., 2000;Nowakowski et al., 2013). Numerous studies conducted on various clinical populations have confirmed the association between these two psychological features by evaluating the co-presence of maladaptive defence strategies in response to stressful events (Cascino et al., 2020;Grabe et al., 2000). However, few studies in the ED field have evaluated whether there is a connection between alexithymia, dissociation and psychopathology (De Berardis et al., 2009;Franzoni et al., 2013), and the results are considered preliminary (Longo et al., 2020).
Indeed, not enough is known about the coexistence of emotional dysregulation, dissociation and alexithymia in ED patients nor the possible effects of interventions proposed for treating these constructs.
Thus, this study aims to evaluate whether general and specific psychopathology is worsened by the presence of alexithymia, as the current literature suggests (Gramaglia et al., 2020), and to determine if a multidisciplinary inpatient treatment for EDs can reduce alexithymia and dissociation. Finally, we aim to point out possible relationships among specific and general psychopathological target variables.

Key Practitioner Message
• Alexithymia and dissociation should be taken into consideration in eating disorders assessment and treatment.
• Inpatient eating disorder treatment could improve alexithymia, dissociation and emotional dysregulation.
• The results suggest a specific linkage between alexithymia and eating psychopathology. details). The duration of the treatment was 60 days, in accordance with the National Health System legislation, and patients were admitted to the facility only after at least one outpatient treatment failed.

| Statistical analysis
Baseline differences among patients belonging to diverse diagnostic categories were evaluated with ANOVA and confirmed with an ANCOVA analysis with BMI as a covariate. The sample was then considered as an ED transdiagnostic sample due to the psychopathological similarity. In accordance with data from the literature, we used the TAS-20 cut-off (61 points) to create two subgroups-with and without alexithymia symptomatology-and analyses of the alexithymia subsamples were performed using t tests for independent samples.
Demographic differences between completers and non-completers were evaluated with t tests for independent samples. We conducted a chi-square analysis to evaluate the distribution of the patients with and without alexithymia in the completers and non-completers subsamples. The evaluation of the changes after the treatment was done with paired t tests. We analysed correlations (Pearson's r) to examine correlations between the delta (post-minus pre-treatment) questionnaires' scores. Effect sizes were evaluated using Cohen's d (small <0.5, medium >0.5 and <0.8, large >0.8). The data were analysed using the IBM SPSS Statistics 25.0 software (SPSS, Chicago, IL, USA). To control the multi-comparison bias, we used the Bonferroni correction, and only p values ≤0.01 were considered significant.

| Baseline evaluation
The included sample was composed of 100 female patients with anorexia nervosa (n = 53), bulimia nervosa (n = 36) and binge eating disorder (n = 11). The mean age was 28.27 ± 12.07 years (14-60 years), and the mean BMI was 20.76 ± 9.55 kg/m 2 (11.17-64.78 kg/m 2 ). The psychological evaluation of the sample is reported in Table 1. No differences were found between the samples, even when running an ANCOVA analysis with BMI as a covariate.
To measure the differences linked to alexithymia, the patients were divided into two subgroups based on a cut-off score of 61 on the TAS-20 (A+ for scores >61, AÀ for scores <61;Taylor et al., 1996). The A+ subgroup (n = 66) showed significantly higher specific ED psychopathological scores than the other subgroup based on the EDE-Q global score (A+ = 4.01 ± 1.44, AÀ = 3.13 ± 1.55, Specialized multidisciplinary treatment proved to be effective in reducing specific psychopathology and dissociation (see Table 2 for pre-and post-test analysis).

| Correlation analyses
Upon examining the relationships among the differences between discharge and admission of the psychopathological questionnaires of the completers, we found different correlations between variables in the two alexithymia subgroups. Only A+ patients showed correlations between the TAS-20, SCL-90-R, the EDE-Q and the DERS (see Table 3 for details).

| DISCUSSION
Maladaptive personality traits and mental processes, such as alexithymia and dissociation, have been identified as a possible target of ED treatments due to their importance in emotional regulation deficits. In this study, we aim to evaluate (1) the differences in the clinical and psychological presentation of ED patients with and without alexithymia and (2) the effect of a specialized multidisciplinary treatment protocol in reducing these symptoms.
As proved by previous literature, the psychological evaluation at the time of admission to the ward showed that ED patients with alexithymia are characterized by a worse specific ED psychopathology than those without alexithymia (Nowakowski et al., 2013). We only partially confirmed our first hypothesis because we did not find any differences in general psychological symptoms between ED patients with and without alexithymia. This could be due to the severity of the sample included in our study-the patients who were admitted to the residential programme had high levels of depression or anxiety.
Their scores at admission were different from those of outpatients or general populations included in previous studies (Hemming et al., 2019;Lenzo et al., 2020). Alexithymia has shown to be a stable trait in ED patients, even after the reduction of depression and anxiety (Nowakowski et al., 2013), and has been pointed to be the possible explanation of the absence of emotional responses to social exclusion in AN patients . A study with a 3 years follow-up has found that alexithymia have a negative prognostic effect into outcome (Speranza et al., 2007) but data are still preliminary and specific interventions into emotional and feeling   (Torrado et al., 2018). From this prospective, eating could be a dysfunctional coping strategies for emotional dysregulation, and alexithymia could amplified these responses due to the difficulties to understand the own feelings and mental states (Spence & Courbasson, 2012).
The most interesting data from our analysis concern the effect of ED specialized treatment. Indeed, our results provide evidence that a specific treatment approach may help to improve emotional regulation, alexithymia and dissociation. A recent review of the literature has pointed out the absence of longitudinal data about the modification of alexithymia in ED patients (Westwood et al., 2017), and our study could provide the first step in understanding the possible changes of this specific psychological construct after implementing psychotherapeutic approaches in severe patients. Moreover, our data are in line with recent literature, which suggests that using flexible interventions based on the history of patients that includes specific psychological techniques may improve maladaptive schema or behavioural responses (J. Linardon, Fairburn, et al., 2017;Todisco et al., 2020).
When we looked at the effects of the inpatient treatment, we found larger effect sizes in the reduction of DERS and TAS-20 in patients with higher scores of alexithymia compared with the lower scores subgroup. However, the TAS-20 scores remain clinically significant for alexithymia even after the inpatient treatment in A+ patients, data that are corroborated by the literature data that considered this feature as a personality trait (Nowakowski et al., 2013). The changes in the TAS-20 scores are also correlated with a reduction in EDE-Q scores. These results show that there is a linkage between eating psychopathology and alexithymia, and they are in line with previous results that showed a connection between AN outcome and alexithymia (Gramaglia et al., 2020), suggesting that this aspect should be studied across the whole spectrum of EDs. The emotional dysregulation reported and the difficulties in the management of their emotional states are in line with the interpersonal model of EDs (Treasure et al., 2012), and they reinforce the idea that comorbidities in ED patients who receive residential treatment should be systematically evaluated and taken into consideration in the therapeutic protocol (Thompson-Brenner et al., 2019).
Despite the number of patients included in this research study, our results should be considered to have several limitations. First, the included sample was predominantly composed of AN patients, even though no psychological differences emerged between subgroups.
Second, we included only female patients, which reduces confounding factors but limits the generalization of the results. Third, the psychological evaluations were only based on self-reported questionnaires.
Future studies should include more bulimia nervosa and binge eating disorder patients and men, and they should use neuropsychological evaluations of emotional recognition and management.
T A B L E 3 Correlations in completers among the differences of the psychopathological variables due to the inpatient treatment (discharge -Admission). In conclusion, our results show that emotional regulation, alexithymia, and dissociation could be improved with specific inpatient treatment in ED patients, despite the limits of the study. Despite significant reduction, the TAS-20 scores remained clinically significant in patients with alexithymia features, corroborating the evidence of its nature as a personality trait. Finally, we found correlations between the changes of alexithymia symptomatology and specific ED psychopathology and changes in emotional regulation, which should be further investigated due to their relevance as it pertains to treatment outcomes.

CONFLICT OF INTEREST
On behalf of all authors, the corresponding author states that there is no conflict of interest.

DATA AVAILABILITY STATEMENT
The clinical data are not publicly available due to privacy and ethical restrictions.