Minako Deno

The Keio Twin Research Center (KoTReC) was established in 2009 at Keio University to combine two longitudinal cohort projects - the Keio Twin Study (KTS) for adolescence and adulthood and the Tokyo Twin Cohort Project (ToTCoP) for infancy and childhood. KoTReC also conducted a two-time panel study of self-control and psychopathology in twin adolescence in 2012 and 2013 and three independent anonymous cross-sectional twin surveys (ToTcross) before 2012 - the ToTCross, the Junior and Senior High School Survey and the High School Survey. This article introduces the recent research designs of KoTReC and its publications.

Introduction: The current study investigated whether the influence of alexithymia on psychological distress (PD) differed according to the seriousness of complicated grief (CG) and the time since bereavement in the Japanese general population. Methods: 1162 participants between 40 and 79 years of age (effective response rate: 58.8%) completed a cross-sectional anonymous questionnaire regarding the following factors: alexithymia (DD: Difficulty describing feeling, DI: Difficulty identifying feeling, EO: Externally oriented thinking), PD, and CG. To compare the non-bereaved (group 1) with four other groups, which were organized by CG score (high/low) and the time since bereavement (within half/two years postloss); the half year_low/high CG (group 2 and 3) and the two years_low/high CG (group 4 and 5), a simultaneous analysis of the five groups with standard maximum likelihood estimations was performed and hypothesized models were verified. Results: The model (RMSEA=0.000, AIC=57.686) showed that the models' constructions for group 1 and 4 were significantly similar. In the other groups, the degree of correlation between alexithymia (especially EO) and psychological distress was significantly different. Limitations: The study is a cross-sectional design and not with a clinical population. Conclusions: Our findings showed that the relationship between alexithymia and psychological distress was significantly same for group 1 and 4. In group 2, EO was less correlated with the other subscales of alexithymia, which suggests that EO is utilized as a coping style for bereavement that, in turn, influences convalescence during the half year following bereavement. (C) 2013 Elsevier BY. All rights reserved.

The Keio Twin Research Center has conducted two longitudinal twin cohort projects and has collected three independent and anonymous twin data sets for studies of phenotypes related to psychological, socioeconomic, and mental health factors. The Keio Twin Study has examined adolescent and adult cohorts, with a total of over 2,400 pairs of twins and their parents. DNA samples are available for approximately 600 of these twin pairs. The Tokyo Twin Cohort Project has followed a total of 1,600 twin pairs from infancy to early childhood. The large-scale cross-sectional twin study (CROSS) has collected data from over 4,000 twin pairs, from 3 to 26 years of age, and from two high school twin cohorts containing a total of 1,000 pairs of twins. These data sets of anonymous twin studies have mainly targeted academic performance, attitude, and social environment. The present article introduces the research designs and major findings of our center, such as genetic structures of cognitive abilities, personality traits, and academic performances, developmental effects of genes and environment on attitude, socio-cognitive ability and parenting, genes x environment interaction on attitude and conduct problem, and statistical methodological challenges and so on. We discuss the challenges in conducting twin research in Japan.

Objective: Although social support has been recognized as an important factor in the quality of life of head and neck cancer patients, there has been little investigation of the buffering effect of social support on these patients' social distress or of the coping skill of self-efficacy. The aim of this study was to examine how social support and self-efficacy mediate the relationship between social distress and emotional distress in head and neck cancer patients. Methods: Two hundred twenty-five head and neck cancer patients completed our questionnaire (effective response rate, 92.2%). Of these, 129 (57.3%) had facial disfigurement. These participants responded to questions about perception of social distress, social support, self-efficacy, and emotional distress (depression and anxiety). We used structural equation modeling for statistical analysis. Results: The fit indices of this model were excellent (chi(2) (7) 59.147, p50.242, goodness of fit index (GFI) 50.981, adjusted goodness of fit index (AGFI) 50.922, comparative fit index (CFI) 50.993, root mean square error of approximation (RMSEA) 50.049). Self-efficacy strongly buffered the negative influence of social distress on emotional distress. Social support from family members did not have a direct or indirect influence on emotional distress. Social support from friends was related to lower social distress and higher emotional distress. Conclusions: Our findings suggest that self-efficacy might confound the relationship between social support and emotional distress, and that different sources of social support might play different roles in the mediation of social distress on emotional distress. Copyright (C) 2010 John Wiley & Sons, Ltd.

Background: The present research investigated whether the relationship between alexithymia and complicated grief was different from the relationship between alexithymia and general depressive symptom according to the seriousness of complicated grief in the Japanese general population. Methods: In the Japanese general population sample, 948 participants between 40 and 79 years old (effective response rate, 48.0%) completed a cross-sectional anonymous questionnaire about alexithymia, depression, and complicated grief. To compare the high risk (n = 243) and low risk (n = 705) of complicated grief groups, simultaneous analysis of two groups with standard maximum likelihood estimation was performed and six hypothesized models were verified. Results: The model (RMSEA = 0.047, AIC = 71.520) that showed that the path coefficients of the latent variable of alexithymia to the observed variables were equal and that the path coefficient of alexithymia to psychological distress was equal was adopted. The contribution ratios from alexithymia to complicated grief were apparently smaller (2-4%) than those to depression (37-38%). Conclusions: Our findings showed that alexithymia scarcely contributed to complicated grief compared to depression and that the contribution ratio in the high risk group was lower than that in the low risk group. The contribution of the latent variable of psychological distress to complicated grief and depression was lower in the high risk group than in the low risk group. The lack of a correlation between alexithymia and complicated grief might indicate that there are different mechanisms underlying the symptoms of alexithymia and complicated grief. (C) 2011 Elsevier B.V. All rights reserved.

Objective: This study assessed the factor structure, internal consistency, and concurrent and discriminant validity of a scale used to measure social distress in Japanese head and neck cancer outpatients with facial disfigurement. Method: The sample included 225 Japanese outpatients with head and neck cancer, including 129 patients with facial disfigurement. Participants' level of social distress was assessed through our scale, the European Organization for Research and Treatment Cancer questionnaire (EORTC) QLQ-H&N35 and the Hospital Anxiety and Depression scale (HADS). Results: Factor analyses confirmed the structure of two subscales of the social distress scale. Social distress was significantly correlated with the social contact subscale of the EORTC QLQ-H&N35 and the HADS. Significance of results: Results demonstrated preliminary reliability and validity of the social distress scale. This scale may extend social adjustment research by revealing its determinants and effects for head and neck cancer with facial disfigurement in Japan.