Uncovering associations between gender nonconformity, psychosocial factors, and mental health in adolescents: a birth cohort study.

BACKGROUND: Little information is available on the association between gender nonconformity during adolescence and subsequent mental health. While the distress related to gender nonconformity may be socially produced rather than attributed to individual-level factors, further research is needed to better understand the role of psychosocial factors in this context. METHOD: We analyzed data from the Tokyo Teen Cohort, obtained through random sampling of adolescents born between 2002 and 2004. We used inverse probability weighting to examine the association of gender nonconformity at ages 12 and 14 as a time-varying variable with subsequent mental health at age 16, while accounting for time-fixed and time-varying confounders. Furthermore, we used a weighting approach to investigate the mediating role of modifiable psychosocial factors in this association, addressing exposure-mediator and mediator-mediator interactions. RESULTS: A total of 3171 participants were analyzed. Persistent gender nonconforming behavior at ages 12 and 14 was associated with subsequent depression (ß = 2.02, 95% confidence interval [CI] 0.85 to 3.19) and psychotic experiences (ß = 0.33, 95% CI 0.14 to 0.52) at age 16. The results remained robust in sensitivity analyses. Approximately 30% of the association between gender nonconformity and depression was consistently mediated by a set of psychosocial factors, namely loneliness, bullying victimization, and relationships with mother, father, and friends. CONCLUSIONS: Persistent gender nonconformity during adolescence is associated with subsequent mental health. Psychosocial factors play a vital mediating role in this association, highlighting the essential need for social intervention and change to reduce stigmatization and ameliorate mental health challenges.

In the face and neck, keloid scar distribution is related to skin thickness and stiffness changes associated with movement.

Keloid scars tend to occur in high-tension sites due to mechanical stimuli that are involved in their development. To date, a detailed analysis of keloid distribution focused specifically on facial and neck areas has not been reported, and limited literature exists as to the related mechanical factors. To rectify this deficiency of knowledge, we first quantified the facial and neck keloid distribution observed clinically in 113 patients. Subsequently, we performed a rigorous investigation into the mechanical factors and their associated changes at these anatomic sites in healthy volunteers without a history of pathologic scarring. The association between keloid-predilection sites and sebaceous gland-dense and acne-prone sites was also examined. To assess skin stretch, thickness and stiffness, VECTRA, ultrasound and indentometer were utilised. Baseline skin stiffness and thickness were measured, as well as the magnitude of change in these values associated with facial expression and postural changes. Within the face and neck, keloids were most common near the mandibular angle (41.3%) and lateral submental (20.0%) regions. These areas of increased keloid incidence were not associated with areas more dense in sebaceous glands, nor linked consistently with acne-susceptible regions. Binomial logistic regression revealed that changes in skin stiffness and thickness related to postural changes significantly predicted keloid distribution. Skin stiffness and thickness changes related to prolonged mechanical forces (postural changes) are most pronounced at sites of high keloid predilection. This finding further elucidates the means by which skin stretch and tension are related to keloid development. As a more detailed analysis of mechanical forces on facial and neck skin, this study evaluates the nuances of multiple skin-mechanical properties, and their changes in a three-dimensional framework. Such factors may be critical to better understanding keloid progression and development in the face and neck.

Longitudinal associations between subjective cognitive impairment, pain and depressive symptoms in home-dwelling older adults: Modelling within-person effects.

OBJECTIVES: Cognitive impairment, pain and depressive symptoms are common and interrelated factors in older adults. However, the directionality and specificity of their association remains unclarified. This study explored whether these factors prospectively increase reciprocal risk and examined the longitudinal association between these factors and quality of life (QoL). METHODS: This study used longitudinal data from The Older Persons and Informal Caregivers Survey Minimal Data Set (TOPICS-MDS; the Netherlands). Older adults self-reported cognitive impairment, pain, depressive symptoms and QoL at baseline and after 6 and 12 months of follow-up. The Random Intercept Cross-Lagged Panel Model was used to assess the prospective association between the three factors, while a multilevel linear regression analysis in a two-level random intercept model was used to examine the longitudinal associations between the three factors and QoL at the within-person level. RESULTS: The data of 11,582 home-dwelling older adults with or without subjective cognitive impairment were analysed. At the within-person level, pain at 6 months was associated with subsequent depressive symptoms (ß = 0.04, p = 0.024). The reverse association from depression to pain, and longitudinal associations between pain and subjective cognitive impairment and between depressive symptoms and subjective cognitive impairment were non-significant. Pain, depressive symptoms and subjective cognitive impairment showed a significant association with poor QoL 6 months later. CONCLUSIONS: A directional relationship was observed from pain to depressive symptoms. Pain reduction holds a potential benefit in the prevention of depressive symptoms, ultimately optimising the QoL of older adults.

Application of extended ulnar parametacarpal perforator free flap for the reconstruction of total pulp defect of the thumb: A case report.

Many procedures are available for the coverage of thumb pulp defects; however, to gain thumb function and esthetics, a similar tissue is desirable. If the length of the longitudinal defect is <2 cm, a volar advancement flap is appropriate; however, if the flap is >2 cm long or wider, retrograde or free flaps are required. Here, we present a case of thumb pulp reconstruction using an extended ulnar parametacarpal perforator (UPM) flap, which achieved excellent functional and esthetic outcomes. A 46-year-old man underwent reconstruction surgery of his thumb, which was a degloved total pulp. A sensate 5.2 × 3.2 cm UPM flap was designed on the ulnar side of the right palm and transferred to his thumb. The flap donor site was covered with a V-Y advancement flap on the dorsal side of the right hand. At 12 months postoperatively, the patient achieved a functional and natural thumb appearance with high satisfaction. The UPM flap can offer soft tissue similar to the pulp region in the digit without a palm scar at the donor site. This extended application is suitable for the reconstruction of a total pulp defect of the digit and is an alternative option for a hemi-pulp flap from the toe area.

Adolescent psychotic experiences before and during the COVID-19 pandemic: a prospective cohort study.

BACKGROUND: Understanding the etiology of psychosis is essential to the development of preventive interventions. The COVID-19 pandemic provides a rare natural experiment that can expand our understanding of the role of social factors in the trajectories and etiology of psychosis across adolescence, particularly in Tokyo where the prevalence of actual COVID-19 infection remained low. We hypothesized that the likelihood of self-reporting psychotic experiences (PEs) would increase following the onset of the COVID-19 pandemic. METHODS: The Tokyo Teen Cohort (TTC) is a prospective cohort study of adolescents in the general population of the Tokyo metropolitan area, followed from age 10 to 16 years. We used multi-level linear regression models to test the associations between the phase of the COVID-19 pandemic and self-reported PEs. RESULTS: Among 1935 adolescents included in the analysis, a rapid increase in PEs occurred at the onset of the COVID-19 pandemic, following approximately 6 years of steady decline across prior waves. This association was more pronounced for boys compared to girls. This increase became more pronounced as the pandemic moved into later phases, defined based on contemporaneous sociopolitical changes in Tokyo (i.e. changes to school closure, social distancing guidelines, and the state of emergency status). CONCLUSIONS: The steady decline in PEs across adolescence was halted and reversed concurrent with the COVID-19 pandemic onset, despite very low rates of COVID-19 infection. This implicates COVID-19 related socioenvironmental factors as contributory etiological factors in the development of PEs in this adolescent cohort.

Medical, welfare, and educational challenges and psychological distress in parents caring for an individual with 22q11.2 deletion syndrome: A cross-sectional survey in Japan.

Parents of children with 22q11.2 deletion syndrome (22q11DS) experience distress not only due to multimorbidity in the patients, but also due to professionals' lack of understanding about 22q11DS and insufficient support systems. This study investigated relationships between medical, welfare, and educational challenges and parental psychological distress. A cross-sectional survey was conducted on primary caregivers of children with 22q11DS. Participants included 125 parents (114 mothers, 91.2%; average age = 44.3 years) who reported their challenges, psychological distress, and child's comorbidities of 22q11DS. Results showed that the difficulty in going to multiple medical institutions (ß = 0.181, p < 0.05) and lack of understanding by welfare staff and insufficient welfare support systems for 22q11DS (ß = 0.220-0.316, all p < 0.05) were associated with parental psychological distress, even after adjusting for child's comorbidities. In the subsample of parents whose child attended an educational institution, inadequate management in classroom and mismatch between service and users in educational settings were associated with psychological distress (ß = 0.222-0.296, all p < 0.05). This study reveals the importance of assessing not only severity of comorbidities in 22q11DS, but also the medical, welfare, and educational challenges for parental mental health.

Trajectory and course of problematic alcohol use after the Great East Japan Earthquake: Eight-year follow-up of the Higashi-Matsushima cohort study.

BACKGROUND: Problematic alcohol use (PAU) after natural disasters is an unignorable public health issue. However, the long-term trajectory and course of PAU after an earthquake disaster remain unknown. METHODS: The Higashi-Matsushima cohort study was conducted between 2012 (time 1) and 2019 (time 8) in areas affected by the Great East Japan Earthquake in 2011. In the annual health checks, participants responded to self-report questionnaires on PAU, traumatic experiences (e.g., house damage), resources (e.g., social support), and other covariates (e.g., gender, psychological distress). The trajectory and course of PAU were estimated by latent growth model and latent class analyses. Risk factors for the long-term course of PAU were calculated by multinomial logistic regression analysis with multiple imputation. The analytical sample comprised 8929 residents who participated in at least one survey across the eight time points. RESULTS: The trajectory of PAU showed a sustained trend (slope <0.001). Three potential courses of PAU (No PAU course: 84.3%, Subthreshold PAU course: 12.4%, and Persistent PAU course: 3.4%) were estimated. The long-term course of PAU, especially the persistent PAU course, was predicted by house damage (OR = 1.43, 95% CI 1.06 to 1.92), less social support (OR = 0.71, 95% CI 0.53 to 0.96), gender (male) (OR = 16.86, 95% CI 9.42 to 30.20), and psychological distress (OR = 1.15, 95% CI 1.09 to 1.20). CONCLUSIONS: Long-term support is needed after an earthquake disaster, especially for residents who in early phases of the disaster suffer from PAU, males, and those in vulnerable situations resulting from conditions such as severe house damage, low social support, or high psychological distress.

Identifying Predictors of Radiographic Distal Phalangeal Nonunion After Fingertip Replantation.

PURPOSE: This study aimed to estimate the risk factors for distal phalangeal nonunion in cases involving Kirchner wire fixation after successful fingertip replantation. METHODS: This study retrospectively analyzed 116 digits of 111 patients, including 74 and 42 digits with replantation in Tamai zones I and II, respectively. Univariate and multivariable analyses were performed to assess the influences of 15 independent variables on nonunion, including age, sex, medical history of diabetes mellitus, history of smoking, injured hand and digit, injury type (clean, blunt, and crush-avulsion), amputation type (complete or incomplete), length of the distal bone fragment (mm), fracture type (simple or comminuted), presence of a bone defect, length of the fracture gap after fixation (mm), number of Kirchner wires used, evidence of venous repair, and the occurrence of pin tract infections after fixation. RESULTS: At 12 months after replantation, 100 digits showed bony union and 16 (13.8%) digits showed radiographic nonunion or equivalent complications, including 9 digits with asymptomatic nonunion without a secondary operation, 5 that underwent an additional operation for nonunion or a complication, and 2 with distal bone resorption. A multivariable analysis indicated that the postfixation fracture gap was the only significant predictor influencing nonunion (odds ratio, 3.30; 95% confidence interval, 1.92-5.68). CONCLUSIONS: The extent of the postfixation fracture gap had the greatest influence on preventing distal phalangeal nonunion, indicating the importance of reducing the fracture gap in primary fixation as much as possible. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Use of social networking sites and desire for slimness among 10-year-old girls and boys: A population-based birth cohort study.

OBJECTIVE: Desire for slimness (DS) is a well-established risk factor for eating disorders among adolescents, particularly girls. It is known that exposure to traditional media such as television can increase DS. However, the association between DS and the use of new media, such as social networking sites (SNS), adjusting for relevant potential confounders, has not been examined to-date. In this study, we assessed the relationship between DS and SNS use among early adolescent girls and boys, adjusting for body mass index (BMI), time spent watching television, and Internet use. METHOD: DS, SNS use, and confounding variables were assessed using self-report questionnaires and face-to-face interviews from a cross-sectional population-based survey of 4,478 10-year-old Japanese adolescents (2,100 girls and 2,378 boys). RESULTS: After adjusting for confounding variables, SNS use was associated with increased risk of DS among girls (odds ratio [OR] = 1.93; 95% confidence interval [CI], 1.17-3.18, p = .010), but not among boys (OR = 1.07; 95% CI, 0.64-1.80, p = .786). DISCUSSION: Exposure to SNS was associated with an increased risk of DS among early adolescents, especially girls. Targeting SNS use in early adolescence seems a promising approach to prevention of DS and subsequent eating problems, particularly among girls.

A quasi-cluster randomized controlled trial of a classroom-based mental health literacy educational intervention to promote knowledge and help-seeking/helping behavior in adolescents.

INTRODUCTION: School-based education is a potentially effective approach for improving mental health literacy (MHL) in adolescents. This study evaluated the effects of the "Short MHL Program (SMHLP)", a brief (50 min), school teacher-led program, on MHL in adolescents in a quasi-cluster randomized controlled trial. METHODS: A total of 975 high school first graders (age 15-16) in Japan were allocated to classes such that gender and academic achievement ratios were almost equivalent at the time of admission to the high school. They were assigned at the class level to the SMHLP (n = 364 from 10 classes) or a control group (n = 611 from 17 classes). The program consisted of a 50-minute session and was delivered by a school teacher. The students completed a self-report questionnaire at 3 time points: pre-, (immediately) post- and 2-month follow-up. Outcomes included "Knowledge about mental health/illnesses", "Recognition of the necessity to seek help", "Intention to seek help", and "Intention of helping peers". Mixed effects modeling was employed for analyses. RESULTS: Scores of all outcomes were significantly improved in the intervention group compared to the control group post-intervention (p < .001). These improvements were maintained at 2-months follow-up for all outcomes (p < .001-.05). Questionnaire scores did not differ between groups at baseline. CONCLUSIONS: The effect of the SMHLP was confirmed in grade 10 students. Brief, yet effective programs can be a viable option to promote understanding of mental health problems and have the potential to be incorporated into regular school curriculum. ".

Use of a vascularized dorsal sensory branch of an ulnar nerve flap for repairing a proper digital nerve with coverage of a volar soft tissue defect: Report of two cases.

To repair a short nerve gap, autograft, allograft, autogenous, or synthetic conduits are selected, but a vascularized nerve autograft is preferred to obtain a reliable postoperative outcome in the case of an unfavorable wound bed. The purpose of this report is to describe and evaluate two cases of repair of a proper digital nerve and volar soft tissue defect with a vascularized dorsal sensory branch of an ulnar nerve flap. The cases of two men, 40 and 20 years old, who suffered index finger defects due to crush lacerations that required a flap and a nerve graft, are presented. A 4.0 cm × 2.0 cm and a 3.2 cm × 1.6 cm flap, which were nourished by the perforators from the ulnar proper digital artery of the little finger, were elevated from the ulnar side of fifth metacarpal bone head and transferred for coverage of the soft tissue defect. A 4.6-cm and a 3.0-cm vascularized nerve graft was interposed in the nerve gap. The patients' postoperative courses were uneventful, and both patients had no complaints related to the donor site. Static and moving two-point discrimination were 8 and 6 mm, respectively, at 6 months after surgery in the first case and 5 and 3 mm, respectively, at 9 months after surgery in the second case. This flap, which could be elevated in the same operative field with a nerve having similar diameter to that of the proper digital nerve, was useful for repair of a finger volar tissue defect.

Pyridoxamine: A novel treatment for schizophrenia with enhanced carbonyl stress.

AIM: The aim of this clinical trial was to obtain proof of concept for high-dose pyridoxamine as a novel treatment for schizophrenia with enhanced carbonyl stress. METHODS: Ten Japanese schizophrenia patients with high plasma pentosidine, which is a representative biomarker of enhanced carbonyl stress, were recruited in a 24-week, open trial in which high-dose pyridoxamine (ranging from 1200 to 2400 mg/day) was administered using a conventional antipsychotic regimen. Main outcomes were the total change in Positive and Negative Syndrome Scale score and the Brief Psychiatric Rating Scale score from baseline to end of treatment at week 24 (or at withdrawal). RESULTS: Decreased plasma pentosidine levels were observed in eight patients. Two patients showed marked improvement in their psychological symptoms. A patient who harbors a frameshift mutation in the Glyoxalase 1 gene also showed considerable reduction in psychosis accompanied with a moderate decrease in plasma pentosidine levels. A reduction of greater than 20% in the assessment scale of drug-induced Parkinsonism occurred in four patients. Although there was no severe suicide-related ideation or behavior, Wernicke's encephalopathy-like adverse drug reactions occurred in two patients and were completely suppressed by thiamine supplementation. CONCLUSION: High-dose pyridoxamine add-on treatment was, in part, effective for a subpopulation of schizophrenia patients with enhanced carbonyl stress. Further randomized, placebo-controlled trials with careful monitoring will be required to validate the efficacy of high-dose pyridoxamine for these patients.

Disciplinary slapping is associated with bullying involvement regardless of warm parenting in early adolescence.

INTRODUCTION: Bullying among adolescents can cause depression and suicidality. Identifying the risk factors for bullying in early adolescence, when its prevalence tends to increase, would assist in its prevention. Although certain parenting styles are known to be associated with bullying, the association of slapping as a parental disciplinary practice with early adolescent bullying is not sufficiently understood. Furthermore, little is known about how warm parenting modifies this association although slapping and warm parenting are not mutually exclusive. The aim of this study was to investigate the association of slapping with the experience of early adolescent bullying--categorized in terms of victims, bullies, and bully-victims--while considering how warm parenting modifies this association. METHODS: This study used data from the Tokyo Early Adolescence Survey, a cross-sectional survey of 4478 children aged 10 from the general population. Data were collected from both children and their primary parent using self-administered questionnaires and face-to-face interviews. Responses from 4326 participants with no missing data were usable for the current analysis (mean age,  10.2 ±â€¯0.3 years; 53 % boys). RESULTS: Frequent and occasional slapping was associated with increased odds of youth being identified as bullies or bully-victims, even after adjusting for warm parenting. The likelihood of being victims, bullies or bully-victims increased as the frequency of slapping increased. CONCLUSION: Disciplinary slapping was associated with increased odds of bullying in early adolescence, regardless of whether warm parenting was present or not.

Time-specific Errors in Growth Curve Modeling: Type-1 Error Inflation and a Possible Solution with Mixed-Effects Models.

Growth curve modeling (GCM) has been one of the most popular statistical methods to examine participants' growth trajectories using longitudinal data. In spite of the popularity of GCM, little attention has been paid to the possible influence of time-specific errors, which influence all participants at each timepoint. In this article, we demonstrate that the failure to take into account such time-specific errors in GCM produces considerable inflation of type-1 error rates in statistical tests of fixed effects (e.g., coefficients for the linear and quadratic terms). We propose a GCM that appropriately incorporates time-specific errors using mixed-effects models to address the problem. We also provide an applied example to illustrate that GCM with and without time-specific errors would lead to different substantive conclusions about the true growth trajectories. Comparisons with other models in longitudinal data analysis and potential issues of model misspecification are discussed.

The possibility of free tissue transfer as a nutrient flap for critical ischemic foot: A case report.

Microsurgical procedure of free tissue transfer in critical limb ischemia patients with large ulceration has already been established. The nutrient flap concept was that transferred tissue functioned not only to cover the skin defect but also as a supplementary blood supply to the ischemic lower leg. This report showed the justification for this concept, which was rarely discussed. A 58-year-old male patient with progressive forefoot gangrene caused by arteriosclerosis obliterans was presented. The distal bypass procedure was performed as revascularization surgery, and a latissimus dorsi (LD) myocutaneous flap was transplanted to cover ulceration. The arterial pedicle of the flap was anastomosed to the vein graft in an end-to-end manner, and the venous pedicle was anastomosed to the posterior tibialis vein in an end-to-end manner. Bypass graft blood flow went straight to the LD flap only. The postoperative course was uneventful. The free flap and right foot survived successfully and the patient was ambulatory with no recurrence of ulceration wearing order-made shoes more than three years after transplantation. Vessel-selective angiography was performed two months after surgery. An angiographic catheter was inserted into the bypass graft, which ran straight through the flap nutrient artery. The results obtained showed that not only the transferred flap area, but also the remaining original foot soft tissue (including the sole and heel) was clearly visualized radiologically only through the flap nutrient vessel. This findings of the angiography appear to provide direct evidence for the nutrient flap concept.

Incidence of Venous Thromboembolism After Oral Oncologic Surgery With Simultaneous Reconstruction.

PURPOSE: Patients with oral cancer who undergo resection with simultaneous reconstruction are presumed to be at high risk for developing venous thromboembolism (VTE) according to current criteria. The primary purpose of this retrospective study was to report the incidence of VTE after oral cancer surgery requiring primary reconstruction and to identify the potential risk factors for VTE in this population. MATERIALS AND METHODS: This retrospective study evaluated 133 consecutive patients who had undergone oral cancer resection with simultaneous reconstruction from April 2007 through December 2014. Bilateral lower-extremity venous duplex ultrasonography (VDUS) was routinely performed 2 days after surgery. Pulmonary embolism was confirmed with computed tomography. The Caprini risk score (CRS) was obtained for each patient. Patients with and without VTE were compared using the χ2 test and Student t test with some variables. Univariate predictors associated with VTE were entered into a multivariate logistic regression analysis. A P value less than .05 was regarded as indicating statistical significance. RESULTS: The incidence of VTE after oral oncologic surgery with simultaneous reconstruction was 26.3% (35 of 133 patients): deep vein thrombosis (DVT) and pulmonary embolism occurred in 2.3% (3 of 133) and DVT alone was found in 24.0% (32 of 133). Multivariate logistic regression analysis showed that only a high CRS was statistically relevant to VTE occurrence. CONCLUSIONS: Because a high incidence of VTE was found after major oral and maxillofacial surgery, lower-extremity VDUS should be undertaken in patients who undergo oral cancer surgery with simultaneous reconstruction, especially those with a high CRS.

Primary On-top Plasty for Treatment of Short-type Postaxial Polydactyly of the Foot.

BACKGROUND: Postaxial polydactyly of the foot is typically treated with medial or lateral toe ray resection. However, simple ray resection does not always give a natural postoperative appearance, especially for short-type polydactyly. The purpose of this article was to describe our primary operation with on-top plasty for lengthening of short-type postaxial polydactyly. METHODS: Four patients (mean age, 11.3 months) underwent this procedure. Ray transfer was performed at the proximal phalangeal level. Lateral distal and middle phalanges were resected and the medial ray was transferred on top of the remaining lateral proximal phalanx. Preoperative and postoperative toe lengths and complications were evaluated by comparison with the contralateral side on x-ray. RESULTS: All toes were lengthened by a mean of 115.1% from the tip of the distal phalanx to the bottom of the proximal phalanx relative to contralateral side. Appearances were very natural without valgus deformity and hypertrophic scar. And there was no remaining dysfunction in walking after a mean of 21.5 months follow-up. CONCLUSIONS: This on-top procedure is useful for improving toe lengthening and bone alignment correction with minimal functional disturbance.

Esthetic Craniofacial Bony and Skull Base Reconstruction Using Flap Wrapping Technique.

For a safe and esthetic skull base reconstruction combined with repair of craniofacial bone defects, the authors introduce the flap wrapping technique in this study. This technique consists of skull base reconstruction using the vastus lateralis muscle of an anterolateral thigh (ALT) free flap, and structural craniofacial bony reconstruction using an autologous calvarial bone graft. The key to this technique is that all of the grafted autologous bone is wrapped with the vascularized fascia of the ALT free flap to protect the grafted bone from infection and exposure. Two anterior skull base tumors combined with craniofacial bony defects were included in this study. The subjects were a man and a woman, aged 18 and 64. Both patients had preoperative proton beam therapy. First, the skull base defect was filled with vastus lateralis muscle, and then structural reconstruction was performed with an autologous bone graft and a fabricated inner layer of calvarial bone, and then the grafted bone was completely wrapped in the vascularized fascia of the ALT free flap. By applying this technique, there was no intracranial infection or grafted bone exposure in these 2 patients postoperatively, even though both patients had preoperative proton beam therapy. Additionally, the vascularized fascia wrapped bone graft could provide a natural contour and prevent collapse of the craniofacial region, and this gives patients a better facial appearance even though they have had skull base surgery.

On the Mathematical Relationship Between Latent Change Score and Autoregressive Cross-Lagged Factor Approaches: Cautions for Inferring Causal Relationship Between Variables.

The present paper focuses on the relationship between latent change score (LCS) and autoregressive cross-lagged (ARCL) factor models in longitudinal designs. These models originated from different theoretical traditions for different analytic purposes, yet they share similar mathematical forms. In this paper, we elucidate the mathematical relationship between these models and show that the LCS model is reduced to the ARCL model when fixed effects are assumed in the slope factor scores. Additionally, we provide an applied example using height and weight data from a gerontological study. Throughout the example, we emphasize caution in choosing which model (ARCL or LCS) to apply due to the risk of obtaining misleading results concerning the presence and direction of causal precedence between two variables. We suggest approaching model specification not only by comparing estimates and fit indices between the LCS and ARCL models (as well as other models) but also by giving appropriate weight to substantive and theoretical considerations, such as assessing the justifiability of the assumption of random effects in the slope factor scores.

Associations between sleep habits and mental health status and suicidality in a longitudinal survey of monozygotic twin adolescents.

Several epidemiological studies have indicated that there is a relationship between sleep habits, such as sleep duration, bedtime and bedtime regularity, and mental health status, including depression and anxiety in adolescents. However, it is still to be clarified whether the relationship is direct cause-and-effect or mediated by the influence of genetic and other traits, i.e. quasi-correlation. To examine this issue, we conducted a twin study using a total of 314 data for monozygotic twins from a longitudinal survey of sleep habits and mental health status conducted in a unified junior and senior high school (grades 7-12), located in Tokyo, Japan. Three-level hierarchical linear model analysis showed that both bedtime and sleep duration had significant associations with the Japanese version of the 12-item General Health Questionnaire (GHQ-12) score, suicidal thoughts and the experience of self-harm behaviours when genetic factors and shared environmental factors, which were completely shared between co-twins, were controlled for. These associations were statistically significant even after controlling for bedtime regularity, which was also associated significantly with the GHQ-12 score. These suggest that the associations between sleep habits and mental health status were still statistically significant after controlling for the influence of genetic and shared environmental factors of twins, and that there may be a direct cause-and-effect in the relationship in adolescents. Thus, late bedtime and short sleep duration could predict subsequent development of depression and anxiety, including suicidal or self-injury risk. This suggests that poor mental health status in adolescents might be improved by health education and intervention concerning sleep and lifestyle habits.