Interactive effect of sleep duration and physical activity on anxiety/depression in adolescents.

Although effects of sleep duration and physical activity (PA) have been demonstrated on mental health in adolescents, their interactive effect has not been studied. This cross-sectional study first examines this interactive effect on anxiety/depression in adolescents. A total of 983 Japanese students aged 12-17 were studied, using a self-report questionnaire. The interaction of sleep duration and amount of PA and their main effects on anxiety/depression, assessed using the 12-item General Health Questionnaire (GHQ-12), were investigated employing multiple regression, adjusting for grade and sex. Sleep duration and amount of PA were classified as being adequate or not, according to the duration and amount recommended by the National Sleep Foundation and World Health Organization, respectively. As a result, the interaction between sleep duration and amount of PA and their main effects were statistically significant. GHQ-12 score was significantly better in adolescents with either adequate sleep or adequate PA, not both, than those with neither adequate sleep nor adequate PA. The score, however, seemed no further improved in those with both adequate sleep and PA. The present study suggests that effects of sleep and PA on mental health need to be studied with consideration to their interaction.

The association between changes in depression/anxiety and trajectories of psychotic-like experiences over a year in adolescence.

BACKGROUND: Recent cross-sectional studies suggest that psychotic-like experiences (PLEs) are associated with depression and anxiety in adolescents. While longitudinal studies have observed that adolescents suffer more severe symptoms of depression/anxiety when PLEs persist, it remains unclear whether depression/anxiety worsens or improves with PLE emergence or remission, respectively. In this prospective school-based study, we investigated the association between longitudinal changes in depression/anxiety and one-year PLE trajectories in adolescence. METHODS: Nine hundred and twelve adolescents participated in the baseline assessment of PLEs and depression/anxiety; 887 (97.3%) adolescents completed the follow-up assessment one year later. Multilevel analysis was conducted to evaluate the change in depression/anxiety, evaluated using the General Health Questionnaire-12 (GHQ-12), during the year according to PLE trajectory, adjusting for baseline depression/anxiety, gender, age, substance use and victimization. RESULTS: Sixteen percent of adolescents reported PLEs at baseline, with 56% of them remitting at follow-up. At follow-up, PLEs were experienced by 6.6% of adolescents not experiencing PLEs at baseline (incident PLE group). After adjusting for covariates, GHQ-12 score worsened significantly during the year in students with incident trajectories (regression coefficient for time, α1=1.91, 95% CI: 1.04-2.77), but in those showing remission, GHQ-12 score did not significantly improve (α1=-0.20, 95% CI: -0.97-0.56). CONCLUSIONS: Greater awareness about PLEs and their trajectories in school health care settings may be a key towards the prevention and treatment of adolescent depression and anxiety.

Annual longitudinal survey at up to five time points reveals reciprocal effects of bedtime delay and depression/anxiety in adolescents.

OBJECTIVE: To investigate the longitudinal relationship between sleep habits and mental health in adolescents. METHODS: Multipoint observation data of up to five years were employed from a prospective cohort study of sleep habits and mental health status conducted from 2009 to 2013 in a unified junior and senior high school (grades 7-12) in Tokyo, Japan. A total of 1078 students answered a self-report questionnaire, including items on usual bed and wake-up times on school days, and the Japanese version of the 12-item General Health Questionnaire (GHQ-12). RESULTS: Latent growth model (LGM) analysis, which requires three or more time point data, showed that longitudinal changes in bedtime and GHQ-12 score (or score for depression/anxiety) were significantly and moderately correlated (correlation coefficient = 0.510, p < 0.05). Another result of interest was that, using an autoregressive cross-lagged (ARCL) model, bedtime and the depression/anxiety score had reciprocal effects the following year: ie, bedtime significantly affects the following year's depression/anxiety, and vice versa. In addition, the analysis provided estimates of mutually predicted changes: one-hour bedtime delay may worsen the GHQ-12 score by 0.2 points, and one-point worsening of the score may delay bedtime by 2.2 minutes. CONCLUSIONS: By using up to five multiple time point data, the present study confirms the correlational and reciprocally longitudinal relationship between bedtime delay and mental health status in Japanese adolescents. The results indicate that preventing late bedtime may have a significant effect on improving mental health in adolescents.

Enzymatic characterization and gene identification of aconitate isomerase, an enzyme involved in assimilation of trans-aconitic acid, from Pseudomonas sp. WU-0701.

UNLABELLED: trans-Aconitic acid is an unsaturated organic acid that is present in some plants such as soybean and wheat; however, it remains unclear how trans-aconitic acid is degraded and/or assimilated by living cells in nature. From soil, we isolated Pseudomonas sp. WU-0701 assimilating trans-aconitic acid as a sole carbon source. In the cell-free extract of Pseudomonas sp. WU-0701, aconitate isomerase (AI; EC 5.3.3.7) activity was detected. Therefore, it seems likely that strain Pseudomonas sp. WU-0701 converts trans-aconitic acid to cis-aconitic acid with AI, and assimilates this via the tricarboxylic acid cycle. For the characterization of AI from Pseudomonas sp. WU-0701, we performed purification, determination of enzymatic properties and gene identification of AI. The molecular mass of AI purified from cell-free extract was estimated to be ~ 25 kDa by both SDS/PAGE and gel filtration analyses, indicating that AI is a monomeric enzyme. The optimal pH and temperature of purified AI for the reaction were 6.0 °C and 37 °C, respectively. The gene ais encoding AI was cloned on the basis of the N-terminal amino acid sequence of the protein, and Southern blot analysis revealed that only one copy of ais is located on the bacterial genome. The gene ais contains an ORF of 786 bp, encoding a polypeptide of 262 amino acids, including the N-terminal 22 amino acids as a putative periplasm-targeting signal peptide. It is noteworthy that the amino acid sequence of AI shows 90% and 74% identity with molybdenum ABC transporter substrate-binding proteins of Pseudomonas psychrotolerans and Xanthomonas albilineans, respectively. This is the first report on purification to homogeneity, characterization and gene identification of AI. DATABASE: The nucleotide sequence of ais described in this article is available in the DDBJ/EMBL/GenBank nucleotide sequence databases under the Accession No. LC010980.

Effects of school-based mental health literacy education for secondary school students to be delivered by school teachers: A preliminary study.

AIMS: Improving knowledge and beliefs about mental health (or mental health literacy [MHL]) may promote appropriate help-seeking by adolescents who are suffering from mental health problems. We developed a concise, school-staff-led MHL program and examined its effects. METHODS: The participants comprised 118 grade-9 students (61 boys and 57 girls). The program consisted of two 50-min sessions, and was given by a schoolteacher. The effects of the program were evaluated before, immediately after and 3 months after the program, using a self-report questionnaire. RESULTS: Knowledge of mental health/illnesses and desirable behavior for help-seeking were significantly improved immediately after (post-test, P < 0.001, and P < 0.001, respectively) and 3 months after the program (3-month follow up, P < 0.001 and P < 0.001, respectively), compared with the test before the delivery of the program (pre-test, Wilcoxon signed rank test). Proportions of the correct diagnoses of vignette cases of major depression and schizophrenia were significantly (P < 0.001) elevated from 38.3% and 19.1% (pre-test) to 94.7% and 93.6% (post-test), and 91.5% and 86.2% (3-month follow up). Intentions to seek help and to provide peers with help with mental health problems were also significantly (P < 0.001) elevated at post-test and at 3 months compared with the pre-test. CONCLUSIONS: A concise, school-staff-led program may have a significant effect on the improvement of MHL in secondary school students.

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.