“A limited ability in understanding, processing, or describing one’s own feelings is generally referred to as “alexithymia,” and literally means “no words for feelings.” P.E. Sifneos (1) introduced this concept from his observations of psychosomatic patients who had “deficits in identifying, describing, and working with their own feelings as well as difficulty in distinguishing between their feelings and bodily sensations of emotional arousal.” Nemiah, Freyberger, and Sifneos later refined the alexithymia construct to include “a paucity of a fantasy and operative thinking as well as difficulty identifying and describing feelings” (2, 3). More recently, alexithymia has been used with broader populations with common medical and psychiatric disorders (4).

Several self-report measures of alexithymia have been developed, and the twenty-item Toronto Alexithymia Scale (TAS-20), one of the most widely used inventories (5, 6), has been translated into various languages, including Japanese (7–9). It has a three-factor structure: “Difficulty identifying feelings (DIF), difficulty describing feelings to others (DDF), and externally oriented thinking (EOT).” TAS-20 has provided a reliable, valid method for measuring alexithymia in both research and clinical practice. However, TAS-20 has been criticized for not including items of imaginal processes that directly assess the construct describing fantasies in the original TAS-26 (10–12). In addition, there are debates about whether or not a self-report scale like TAS-20 should be used to assess a construct that involves impairments in self-awareness (10–14). TAS-20 scoring may be influenced by negative affectivity (15–17).

When TAS-20 was administered concurrently with the NEO-Five Factor Inventory to a large number of nonclinical subjects (n=2,188), the results identified two subgroups with high TAS-20 scores (18): one with high scores for difficulty identifying feelings (DIF) and neuroticism on NEO-FFI and the other with high scores for externally oriented cognitive style and low openness to experience of NEO-FFI. These results suggest that the total score on the TAS-20 should not be considered a unidimensional measure of alexithymia.

Based on the above findings and others, the main problem with the alexithymia construct has always been its measurement. Because there are currently no uniform methods for evaluating alexithymia in a clinical setting, we translated the twelve-item modified version of the Beth Israel Hospital Psychosomatic Questionnaire (M-BIQ) (19, 20) into Japanese: the original BIQ is the first objective alexithymia scale that was developed by Sifneos (2). M-BIQ is an observer-rated measure with 12 items: nine items of the original BIQ were eliminated and four new items added. Six items assess the ability to identify and verbally communicate feelings (i.e., affect awareness) and six items assess imaginal activity and externally oriented thinking (i.e., operatory thinking, or pensée opératoire). Subsequently, we developed our Structured Interview (SIBIQ) to supplement TAS-20 for use with patients with psychosomatic symptoms (7). Factor analysis of the SIBIQ extracted alexithymia and fantasy ability as significant. We then did a similar investigation of healthy people with no or fewer symptoms, which was necessary to newly develop a modified structure interview format for the Japanese version of the M-BIQ (m-SIBIQ) for a broader population.

An observer-rated interview method, the Toronto Structured Interview for Alexithymia (TSIA), was reported in 2006 by Bagby et al. (21). The alexithymia construct of the TSIA is composed of the three facets of TAS-20 (DIF, DDF and OT) with an additional facet, fantasy and other imaginal processes (IMP). Although the construct validity has been reported to be excellent (22, 23), it needs special training for valid scoring of the 24 items and requires controlling for negative affectivity (23).

Herein, we examine and confirm the reliability and validity of our Japanese version of the m-SIBIQ.

The purposes of the present study were to develop a structured interview for alexithymia and to assess its reliability and validity for use with m-SIBIQ. The reliability, construct, and concurrent and discriminant validity of this m-SIBIQ were evaluated, and it was found to be reliable and valid for the assessment of alexithymia in Japan.

The total m-SIBIQ score model extracted one personality domain, a low score for Openness to Experience (NEO-FFI). Among the other independent items, high Emotionally Chilly (EES) and DDF (TAS-20) scores were extracted. Low Openness to experience and high Emotional Chill represent generally recognized characteristics of alexithymia (3, 41, 42). It is interesting that DDF rather than DIF was extracted as a typical TAS-20 subscale. It is said that the total TAS-scale is generally reliable, yet, the subscale scores can have an added value beyond the total scale score (42). The implication of this is that findings related to TAS DDF make a positive contribution to the m-SIBIQ total score, differently from DIF. TAS DIF was originally defined theoretically to distinguish between feelings and bodily sensations of emotional arousal (1), whereas DDF is related to social context like difficulties in social communication. This finding is consistent with Nemiah’s findings (43) that the alexithymia characteristics difficulties in ‘verbalizing’ and ‘analyzing’ represented by DDF and EOT scores have a significant negative relation with Openness to experience. In addition, Emotionally Chilly (EES) well reflects another characteristic of alexithymia that is related to uncooperative and critical interpersonal behaviors (44).

For construct validity, two best models, C and D, were obtained: Model C is composed of the facets Affective Awareness (AA) and Operative Thinking (OT); Model D is composed of Alexithymia (Factor 1) and Fantasy/dreams (Factor 2).

The facets of Model C are consistent with the construct characteristics of BIQ (42, 45) and confirmed the generally accepted structure model of alexithymia as described by Nemiah and Sifneos (2, 3). This construct model is composed of “Affective Awareness” and “Operative Thinking (la pensée opératoire)” components. For the lower facet of Affective Awareness, it extracts the personality trait Extraversion (NEO-FFI) as negative and the EOT factor of TAS-20 as positive. For the lower facet of the Operative Thinking style (la pensée opératoire), it extracts less Openness to Experience trait (NEO-FFI), a tendency toward Emotionally Chilly (EES), and less Fantasy (IRI) life. These findings are consistent with personality findings observed among people with alexithymic characteristics (42, 45).

In contrast, model D is distinguished by two facets of the alexithymia construct: “Fantasy ability” appears to be another independent factor related to “Alexithymia.” This model reconfirms lack of imagination as a concept of the alexithymia model (2), which was supported and measured in the original TAS but was later eliminated from TAS-20 because the validation of the ‘fantasy’ factor was not successfully established as an independent factor (20). Model D was observed previously in a patient group studied for the development of the SIBIQ (19). The facets fantasy and imaginal processes were poorly mapped on the alexithymia construct (45). The negative relation of the Extraversion personality trait to the alexithymia score is not surprising: an extrovert would have the ability to put feelings into words in the interviews, as when participating in a normal social context.

To summarize the findings above, a paucity of openness to experience as a personality trait significantly affects the formation of the total alexithymia characteristics for m-SIBIQ and strongly affects operatory thinking style and fantasy/dreams, which are characterized in the Alexithymia construct (46). The dimensions of personality traits in reports of recent studies are somewhat different from the present m-SIBIQ findings (12, 42, 45, 46). We completely agree with Rosenberg et. al’s concern that the differences are a limitation of almost all recent studies that examine the relation between alexithymia and the personality traits using self-reports like TAS-20 (47).

For discriminative validity, the depression scores of BDI-II were not correlated with m-SIBIQ in the present study. Many studies have shown that when using a self-reported alexithymia questionnaire like TAS-20, alexithymia appears to be associated with depression and anxiety (15–17, 20, 48). Particularly, the facet “difficulty identifying feelings” is related to negative affectivity, but alexithymia differs from depression. People who score high on the subscales of the above facets may be viewed by others as emotionally aware or they may use emotional language in relatively complex ways. Clearly, people with high negative affect differ substantially from those with alexithymia, who are much less interested in their own psychological and emotional lives. Moreover, this type of structured interview has less of an impact than self-evaluation, probably because when people are depressed they may talk less to others. Thus, one of the important findings of this study is that m-SIBIQ is not influenced by negative affectivity, such as depression.

Some reviews across numerous studies on alexithymia have shown a significant correlation with the neuroticism domain. The findings were from both TAS-20 and TAS-26 (10, 12, 46) which are self-reported questionnaires, thus the correlation of alexithymia with neuroticism may represent a method-specific effect (47). The present study of m-SIBIQ, however, supports evidence that, as Sifneos emphasized at every turn, “what is really needed is for physicians to learn to recognize the difference between neurotic and alexithymic patients” (1).

The present findings show a multi-dimensional view of the personality traits and personality type of persons with alexithymia (12). One reason for the absence of alexithymia in DSM-5 may be because of the failure of taxometric studies to identify alexithymia. As empirical evidence has suggested, alexithymia is related inversely to the psychological mindedness and emotional intelligence traits. Also, alexithymia is better thought of as a coping style that is used to defend against emotional distress associated with specific situations, such as trauma or chronic medical illness (49).

Attachment studies have reported an association between alexithymia and an insecure attachment life style in early childhood (50). Openness to experience may be necessary for the regulation of distressing emotions and doing something to change for the better the problem causing the distress (51). It should be emphasized that being open to one’s own feelings is essential. The relation of alexithymia to health and disease will be better clarified by development of the SIBIQ, and it will help with the investigation of various psychosomatic diseases and reduce the risk of their development.

Some limitations of the present study should be noted. First, our sample consisted of only young adults and there was a statistically small number of subjects. Second, all were well educated students, so more heterogeneous samples are necessary. Future research should include a patient group with high alexithymia scores and analysis of test-retest reliability to confirm these results.

The findings of the present study indicate that m-SBIQ is consistent with the most widely used assessments of the alexithymia construct and that it has great potential as a treatment and research tool for not only psychosomatic patients but also those who are difficult to treat in clinical settings. The characteristics identified represent the personality traits openness to experience, difficulty in describing feelings in self-reported expression, and less fantasy life.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The studies involving humans were approved by the ethics committee of International university of health and welfare. The studies were conducted in accordance with the local legislation and institutional requirements. The participants provided their written informed consent to participate in this study.

GK: Writing – original draft, Writing – review & editing, Conceptualization. TB: Formal Analysis, Investigation, Methodology, Writing – review & editing. TY: Formal Analysis, Methodology, Writing – review & editing. TA: Conceptualization, Writing – review & editing. YM: Conceptualization, Writing – review & editing. MM: Conceptualization, Supervision, Writing – review & editing.