Noriko Kato

The Tokyo Twin Cohort Project: Overview and initial findings

The Tokyo Twin Cohort Project (ToTCoP) is a large-scale longitudinal study of 5 years based on 1619 pairs of infant twins reared together. The purpose of the study is to construct a population-based twin registry in Japan and to investigate human growth and development and twin themselves. It covers behavioral, neurological, physical and environmental variables measured by questionnaire, home visiting and brain imaging technology. The full registry contains over 47,000 multiple births collected from the Basic Resident Register, and the targeted population is 3070 probable twins of 0 to 2 years old. Preliminary analysis of the entry questionnaire data showed no serious sampling biases. Descriptive statistics of parental characteristics (parental age, gestation age, parity and placentation, maternal weight, parenting stress) and childrens characteristics (body size at birth, 4 and 10 months of age, milk consumption, and sleeping and social behavior) and their correlations, genetic and environmental contributions and correlations are reported.

Validity and clinical interpretability of Overall Anxiety Severity And Impairment Scale (OASIS).

BACKGROUND The Overall Anxiety Severity and Impairment Scale is a brief generic measure for anxiety that encompasses frequency and intensity as well as behavioral and functional aspects of anxiety. This study was conducted to elucidate aspects of reliability, validity, and interpretability, such as equivalence of factor loadings across non-clinical and clinical populations, convergence and discriminance of related variables, and performance of detecting diagnostic and medical status of anxiety disorders. METHODS Non-clinical and clinical Japanese populations were taken from a panelist pool registered with an internet survey company (total n=2830; 619 panic disorder, 576 for social anxiety disorder, 645 for obsessive-compulsive disorder, a 619 for major depressive disorder, and 371 for non-disorder panelists). Conventional measures of anxiety, depression, mental health and measures for discriminant validity were administered in addition to OASIS. RESULTS Exploratory and confirmatory factor analyses indicated good fit to data for the one-factor model of OASIS. Multi-group confirmatory factor analysis showed the equivalence of the factor loadings between those of non-clinical and clinical subsamples. The OASIS reliability was confirmed by internal consistency and test-retest coefficients. Receiver operating characteristic curve analyses showed that OASIS and conventional anxiety measures have fair performance for detecting diagnostic and medical status as anxiety disorders. LIMITATIONS Participants were limited to a Japanese population of people who had registered themselves at an internet survey company. CONCLUSIONS Along with useful information to interpret OASIS, the results suggest the reliability and validity of OASIS in Japanese populations. These results also suggest cross-cultural validity.

The relationship between birthweight discordance and perinatal mortality of one of the twins in a twin pair.

This study aimed to evaluate the prevalence of birthweight discordance among twins, to determine the risk cut-off point for birthweight discordance, and to clarify whether perinatal deaths are aggravated by birthweight discordance or by low birthweight itself. A population-based analysis of all twins born between 1995 and 1999 in Japan was conducted using data collected from national birth, death and stillbirth certificates. Birthweight discordance was determined as: higher birthweight minus lower birthweight divided by higher birthweight multiplied by 100. Among twins with a birthweight discordance of more than 15%, the fetal and perinatal mortality rate was higher than that of twins with a discordance of less than 15%. Ninety per cent of the relative cumulative frequency of twin live-births were within 25% of the birthweight discordance. Logistic regression analysis showed that the stillbirth of at least one of the twins is associated with the birthweight of the larger twin and birthweight discordance. It also showed that the stillbirth of both twins in the twin pair is associated with the birth-weight of larger twins and the gestational weeks. It was clarified that birthweight discordance was associated with the stillbirth of only one twin in the twin pair, and the stillbirth of both twins in the twin pair was associated with low birthweight itself.

Assessing Depression Related Severity and Functional Impairment: The Overall Depression Severity and Impairment Scale (ODSIS)

Background The Overall Depression Severity and Impairment Scale (ODSIS) is a brief, five-item measure for assessing the frequency and intensity of depressive symptoms, as well as functional impairments in pleasurable activities, work or school, and interpersonal relationships due to depression. Although this scale is expected to be useful in various psychiatric and mental health settings, the reliability, validity, and interpretability have not yet been fully examined. This study was designed to examine the reliability, factorial, convergent, and discriminant validity of a Japanese version of the ODSIS, as well as its ability to distinguish between individuals with and without a major depressive disorder diagnosis. Methods From a pool of registrants at an internet survey company, 2830 non-clinical and clinical participants were selected randomly (619 with major depressive disorder, 619 with panic disorder, 576 with social anxiety disorder, 645 with obsessive–compulsive disorder, and 371 non-clinical panelists). Participants were asked to respond to the ODSIS and conventional measures of depression, functional impairment, anxiety, neuroticism, satisfaction with life, and emotion regulation. Results Exploratory and confirmatory factor analysis of three split subsamples indicated the unidimensional factor structure of ODSIS. Multi-group confirmatory factor analysis showed invariance of factor loadings between non-clinical and clinical subsamples. The ODSIS also showed excellent internal consistency and test–retest intraclass correlation coefficients. Convergence and discriminance of the ODSIS with various measures were in line with our expectations. Receiver operating characteristic curve analyses showed that the ODSIS was able to detect a major depressive syndrome accurately. Conclusions This study supports the reliability and validity of ODSIS in a non-western population, which can be interpreted as demonstrating cross-cultural validity.

Estimation of optimal birth weights and gestational ages for twin births in Japan

BackgroundAs multiple pregnancies show a higher incidence of complications than singletons and carry a higher perinatal risk, the calculation of birth weight – and gestational age (GA)-specific perinatal mortality rates (PMR) for multiple births is necessary in order to estimate the lowest PMR for these groups.MethodsDetails of all reported twins (192,987 live births, 5,539 stillbirths and 1,830 early neonatal deaths) in Japan between 1990 and 1999 were analyzed and compared with singletons (10,021,275 live births, 63,972 fetal deaths and 16,862 early neonatal deaths) in the annual report of vital statistics of Japan. The fetal death rate (FDR) and PMR were calculated for each category of birth weight at 500-gram intervals and GA at four-week intervals. The FDR according to birth weight and GA category was calculated as fetal deaths/(fetal deaths + live births) × 1000. The perinatal mortality rate (PMR) according to birth weight and GA category, was calculated as (fetal deaths + early neonatal deaths)/(fetal deaths + live births) × 1000. Within each category, the lowest FDR and PMR were assigned with a relative risk (RR) of 1.0 as a reference and all other rates within each category were compared to this lowest rate.ResultsThe overall PMR per 1,000 births for singletons was 6.9, and the lowest PMR was 1.1 for birth weight (3.5–4.0 kg) and GA (40- weeks). For twins, the overall PMR per 1,000 births was 36.8, and the lowest PMR was 3.9 for birth weight (2.5–3.0 kg) and GA (36–39 weeks). At optimal birth weight and GA, the PMR was reduced to 15.9 percent for singletons, and 10.6 percent for twins, compared to the overall PMR. The risk of perinatal mortality was greater in twins than in singletons at the same deviation from the ideal category of each plurality.ConclusionPMRs are potentially reduced by attaining the ideal birth weight and GA. More than 90 percent of mortality could be reduced by attaining the optimal GA and birth weight in twins by taking particular care to ensure appropriate pregnancy weight gain, as well as adequate control for obstetric complications.

Two cohort and three independent anonymous twin projects at the Keio Twin Research Center (KoTReC)

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, socio-economic, 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.

The reliability and validity of the Japanese version of the Temperament and Personality Questionnaire for patients with non-melancholic depression.

BACKGROUND Parker et al. (2006) proposed a new approach to classify specific sub-types of non-melancholic depression caused by various stress factors and premorbid personality styles: the Temperament and Personality Questionnaire (T&P). The current study aim was to develop the Japanese version of the T&P and evaluate its reliability and validity. METHODS We studied 114 patients with non-melancholic depression. Reliability was assessed using the test-retest method. Convergent validity of the T&P was compared with the clinician ratings of each patient for the eight personality traits. We also assessed the impact of depressive state on the T&P. RESULTS The test-retest intraclass correlation coefficients among eight constructs of the T&P ranged from 0.77 to 0.89, indicating good-to-excellent reliability. Anxious Worrying (rho=0.29), Perfectionism (rho=0.17), Personal Reserve (rho=0.18), Irritability (rho=0.38), and Social Avoidance (rho=0.32) showed adequate levels of convergent validity; Rejection Sensitivity (rho=0.16), Self-criticism (rho=-0.02), and Self-focus (rho=0.07) showed relatively weak convergent validity. Perfectionism (rho=-0.06), Social Avoidance (rho=0.17), Anxious Worrying (rho=0.40), Personal Reserve (rho=0.30), Irritability (rho=0.28), Rejection Sensitivity (rho=0.35), Self-criticism (rho=0.49), and Self-focus (rho=0.24) showed minimal sensitivity to mood state effects. LIMITATIONS Only one site was used. While a Likert scale was used, the clinician-rated personality trait measure had not been validated. CONCLUSIONS The J-T&P is a reliable and valid measure for assessing temperament and personality in Japanese patients with non-melancholic depression.

Web-Based Cognitive Behavioral Therapy Blended With Face-to-Face Sessions for Major Depression: Randomized Controlled Trial

Background Meta-analyses of several randomized controlled trials have shown that cognitive behavioral therapy (CBT) has comparable efficacy to antidepressant medication, but therapist availability and cost-effectiveness is a problem. Objective This study aimed to evaluate the effectiveness of Web-based CBT blended with face-to-face sessions that reduce therapist time in patients with major depression who were unresponsive to antidepressant medications. Methods A 12-week, assessor-masked, parallel-group, waiting- list controlled, randomized trial was conducted at 3 medical institutions in Tokyo. Outpatients aged 20-65 years with a primary diagnosis of major depression who were taking ≥1 antidepressant medications at an adequate dose for ≥6 weeks and had a 17-item GRID-Hamilton Depression Rating Scale (HAMD) score of ≥14 were randomly assigned (1:1) to blended CBT or waiting-list groups using a computer allocation system, stratified by the study site with the minimization method, to balance age and baseline GRID-HAMD score. The CBT intervention was given in a combined format, comprising a Web-based program and 12 45-minute face-to-face sessions. Thus, across 12 weeks, a participant could receive up to 540 minutes of contact with a therapist, which is approximately two-thirds of the therapist contact time provided in the conventional CBT protocol, which typically provides 16 50-minute sessions. The primary outcome was the alleviation of depressive symptoms, as measured by a change in the total GRID-HAMD score from baseline (at randomization) to posttreatment (at 12 weeks). Moreover, in an exploratory analysis, we investigated whether the expected positive effects of the intervention were sustained during follow-up, 3 months after the posttreatment assessment. Analyses were performed on an intention-to-treat basis, and the primary outcome was analyzed using a mixed-effects model for repeated measures. Results We randomized 40 participants to either blended CBT (n=20) or waiting-list (n=20) groups. All patients completed the 12-week treatment protocol and were included in the intention-to-treat analyses. Participants in the blended CBT group had significantly alleviated depressive symptoms at week 12, as shown by greater least squares mean changes in the GRID-HAMD score, than those in the waiting list group (−8.9 points vs −3.0 points; mean between-group difference=−5.95; 95% CI −9.53 to −2.37; P<.001). The follow-up effects within the blended CBT group, as measured by the GRID-HAMD score, were sustained at the 3-month follow-up (week 24) and posttreatment (week 12): posttreatment, 9.4 (SD 5.2), versus follow-up, 7.2 (SD 5.7); P=.009. Conclusions Although our findings warrant confirmation in larger and longer term studies with active controls, these suggest that a combined form of CBT is effective in reducing depressive symptoms in patients with major depression who are unresponsive to antidepressant medications. Trial Registration University Hospital Medical Information Network Clinical Trials Registry: UMIN000009242; https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000010852 (Archived by WebCite at http://www.webcitation. org/729VkpyYL)

Reliability and validity of the Japanese version of the Emotion Regulation Skills Questionnaire

BACKGROUND The Emotion Regulation Skills Questionnaire (ERSQ) comprehensively assesses nine aspects of emotion regulation skills: awareness, clarity, sensation, understanding, compassionate self-support, modification, acceptance, tolerance, and readiness to confront. However, it is unknown about the levels of emotion regulation skills in various mental disorders, and its cross-cultural validity. We developed a Japanese version of the ERSQ, then examined its validity and reliability in clinical and non-clinical populations. METHODS In an Internet-based survey, 2684 participants (406 with MDD, 198 with PD, 116 with SAD, 66 with OCD, 636 with comorbid MDD and ≥1 anxiety disorder, and 99 with comorbid anxiety disorders; 1163 non-clinical sample) answered the ERSQ, diagnostic status, and measures of mindfulness, emotion regulation, behavioral activation, psychological distress, and life satisfaction. RESULTS Confirmatory factor analysis (CFA) replicated the theoretical nine-factor structure of the original ERSQ. Higher-order factor analysis model assuming two second-order factors and nine first-order factors also showed adequate fit to the data, suggesting the factorial validity of the scale. Analyses of multi-group CFA indicated the equivalence of factor loadings across clinical and non-clinical subsamples. The levels of internal consistency and time stability were sufficient. Convergent validity of the scale was also confirmed for most of external criteria. Character on the emotion regulation skills for each diagnostic group was depicted. LIMITATIONS Internet survey of samples with limited disorders, with self-reported diagnoses, may limit generalizability. CONCLUSIONS The Japanese version of the ERSQ showed adequate reliability and validity.