Blood lead concentrations and attention deficit hyperactivity disorder in Korean children: a hospital-based case control study.

BACKGROUND: Because the developing brain of a child is vulnerable to environmental toxins, even very low concentration of neurotoxin can affect children's neurodevelopment. Lead is a neurotoxic heavy metal which has the harmful effect on the striatal-frontal circuit of brain. This area of the brain is known to be closely related to attention deficit hyperactivity disorder (ADHD) pathophysiology. The primary objective of the present study was to investigate whether elevated blood lead concentration is a risk factor for ADHD. The secondary objective was to examine the association between blood lead concentration and symptom severity. METHODS: We conducted a frequency-matched, hospital-based case-control study with 114 medically diagnosed ADHD cases and 114 controls. The participants were matched for age and sex. The diagnoses of ADHD were assessed with semi-structured diagnostic interviews. The participants completed the continuous performance test (CPT), and their parents completed the ADHD-rating scale (ADHD-RS). Blood lead concentrations were measured by using graphite furnace atomic absorption spectrometry featuring Zeeman background correction. RESULTS: Children with ADHD exhibited blood lead concentrations that were significantly higher than those of the controls ( 1.90 ± 086 µg/dℓ vs. 1.59 ± 0.68 µg/dℓ, p = 0.003). The log transformed total blood lead concentration was associated with a higher risk of ADHD (OR: 1.60, 95 % CI: 1.04-2.45, p < 0.05). The analysis also revealed that the children with blood lead concentrations above 2.30 µg/dℓ were at a 2.5-fold (95 % CI: 1.09-5.87, p < 0.05) greater risk of having ADHD. After adjusting for covariates, our multivariate regression models indicated that blood lead concentrations were not significantly associated with ADHD-RS or CPT profiles among the ADHD cases. CONCLUSION: Even low blood lead concentrations are a risk factor for ADHD in children. This study warrants primary prevention policies to reduce the environmental lead burden. Future studies may be required to ascertain the effects of lead on symptom severity in ADHD.

Protein Kinase C Activity and Delayed Recovery of Sleep-Wake Cycle in Mouse Model of Bipolar Disorder.

OBJECTIVE: Previous studies reported the delayed recovery group after circadian rhythm disruption in mice showed higher quinpiroleinduced locomotor activity. This study aimed to compare not only Protein Kinase C (PKC) activities in frontal, striatal, hippocampus and cerebellum, but also relative PKC activity ratios among brain regions according to recovery of circadian rhythm. METHODS: The circadian rhythm disruption protocol was applied to eight-week-old twenty male Institute Cancer Research mice. The circadian rhythm recovery patterns were collected through motor activities measured by Mlog system. Depressive and manic proneness were examined by forced swim test and quinpirole-induced open field test respectively. Enzyme-linked immunosorbent assay was employed to measure PKC activities. RESULTS: The delayed recovery group presented greater locomotor activities than the early recovery group (p=0.033). The delayed recovery group had significantly lower frontal PKC activity than the other (p=0.041). The former showed lower frontal/cerebellar PKC activity ratio (p=0.047) but higher striatal/frontal (p=0.038) and hippocampal/frontal (p=0.007) PKC activities ratios than the latter. CONCLUSION: These findings support potential mechanism of delayed recovery after circadian disruption in bipolar animal model could be an alteration of relative PKC activities among mood regulation related brain regions. It is required to investigate the PKC downstream signaling related to the delayed recovery pattern.

Early menarche and risk-taking behavior in Korean adolescent students.

INTRODUCTION: The aim of this study is to assess the correlation between early menarche and risk-taking behavior in a representative sample of Korean adolescent students. METHODS: Data were drawn from a cross-sectional, nationally representative sample of 33 829 female adolescents (grades 7-12) from the 2014 Korean Youth Risk Behavior Web-based Survey. Logistic regression analysis was conducted to test the association between early menarche and risk-taking behavior. RESULTS: Female adolescents who experienced menarche at an earlier age tended to have an earlier initiation of sexual intercourse (odds ratio [OR] 4.61, 95% CI, 3.05-6.98, P = .001), smoking (OR 4.29, 95% CI, 3.75-4.9, P < .001), alcohol drinking (OR 1.13, 95% CI, 1.02-1.24, P < .001), and substance use (OR 25.16, 95% CI, 18.78-33.72, P < .001). These adolescents were also at greater risk of pregnancy (OR 4.05, 95% CI, 2.56-6.41, P = .01) and sexually transmitted diseases (OR 2.35, 95% CI, 1.66-3.33, P < .001). DISCUSSION: Early menarche is significantly associated with risk-taking behavior in Korean adolescent students. This finding suggests that early educational intervention and social programs are needed for female adolescents with early menarche.

A study on the relationship between job stress and nicotine dependence in Korean workers.

BACKGROUND: Nicotine dependence and its severity are often determined by individuals' psychosocial factors.This study purposed to analyze how Korean workers' job stress is related with their nicotine dependence according to demographic and occupational characteristics in order to reduce smoking related to job stress and to establish objective indicators to be used in developing adequate smoking cessation strategies. METHODS: The subjects of this study were 4,639 workers who replied to the questionnaire survey. In addition, 1,948 current smokers were separated from non-smokers and ex-smokers, and the relationship between job stress and nicotine dependence was analyzed with the current smoker group. Nicotine dependence was tested using Fagerström's Test of Nicotine Dependence, and stress was measured using a questionnaire on subjective stress felt by workers in their daily life and the short form of the Korean Occupational Stress Scale. RESULTS: The smoking rate was 54.1 % among men and 2.5 % among women. Nicotine dependence was significantly different according to interpersonal conflict, organization system and lack of reward (p < 0.05). As multivariate logistic analysis, job control, occupational climate and total stress score were statistical significant (p < 0.05). CONCLUSIONS: Job stress was found to be related with smoking status and nicotine dependence. Based on this result, it is suggested to enhance workers' welfare for health promotion in workplace by improving their working environment in order to reduce job stress and consequently to decrease the smoking rate.

Times to Discontinue Antidepressants Over 6 Months in Patients with Major Depressive Disorder.

OBJECTIVE: The aim of the present study was to investigate differences in discontinuation time among antidepressants and total antidepressant discontinuation rate of patients with depression over a 6 month period in a naturalistic treatment setting. METHODS: We reviewed the medical records of 900 patients with major depressive disorder who were initially prescribed only one kind of antidepressant. The prescribed antidepressants and the reasons for discontinuation were surveyed at baseline and every 4 weeks during the 24 week study. We investigated the discontinuation rate and the mean time to discontinuation among six antidepressants groups. RESULTS: Mean and median overall discontinuation times were 13.8 and 12 weeks, respectively. Sertraline and escitalopram had longer discontinuation times than that of fluoxetine, and patients who used sertraline discontinued use significantly later than those taking mirtazapine. No differences in discontinuation rate were observed after 24 weeks among these antidepressants. About 73% of patients discontinued antidepressant treatment after 24 weeks. CONCLUSION: Sertraline and escitalopram tended to have longer mean times to discontinuation, although no difference in discontinuation rate was detected between antidepressants after 24 weeks. About three-quarters of patients discontinued antidepressant maintenance therapy after 24 weeks.

Comparison of efficacy and safety of milnacipran and fluoxetine in Korean patients with major depression.

OBJECT: To compare efficacy and safety of milnacipran and fluoxetine in a population of Korean patients with major depression. RESEARCH DESIGN AND METHODS: The design was a multi-centre, randomised, comparative clinical study. Patients with major depression (DSM-IV diagnostic criteria) scoring over 17 points on the 17-item Hamilton Depression Scale (HAM-D) and over 21 points on the Montgomery-Asberg Depression Rating Scale (MADRS) were recruited and randomised to receive milnacipran (50 mg/day increasing after 1 week to 100 mg/day) or fluoxetine (20 mg/day) for 6 weeks. All previous medication was stopped at least 7 days before entry into the study. Patients were evaluated (HAM-D, MADRS and clinical global impression scale, CGI) at baseline and after 1, 2, 4 and 6 weeks of treatment. All adverse events which developed during the study period were recorded. RESULTS: 70 patients (milnacipran 39; fluoxetine 31) were included in the study. Total score on both HAM-D, MADRS and CGI decreased significantly in both groups after 1 week and continued to decrease throughout the study. There was no significant difference between the two groups for any measurement at any time point. Both antidepressants were well tolerated. In the milnacipran group, 13 patients reported 28 adverse reactions, and in the fluoxetine group 11 patients reported 18 adverse reactions. Two patients discontinued due to adverse events in the milnacipran group and three in the fluoxetine group. There were no clinically significant modifications in vital signs, routine blood laboratory tests, biochemistry or ECG throughout the study. Nausea and headache were the most frequently reported adverse events with milnacipran while digestive disturbances, diarrhoea and insomnia were more common with fluoxetine. CONCLUSION: Milnacipran, like fluoxetine, was found to be effective and well tolerated for the treatment of major depression in this population of depressed Korean patients. Principal limitations of the study were its open design, its small sample size and its relatively short duration.

Dietary patterns in children with attention deficit/hyperactivity disorder (ADHD).

The role of diet in the behavior of children has been controversial, but the association of several nutritional factors with childhood behavioral disorders has been continually suggested. We conducted a case-control study to identify dietary patterns associated with attention deficit hyperactivity disorder (ADHD). The study included 192 elementary school students aged seven to 12 years. Three non-consecutive 24-h recall (HR) interviews were employed to assess dietary intake, and 32 predefined food groups were considered in a principal components analysis (PCA). PCA identified four major dietary patterns: the "traditional" pattern, the "seaweed-egg" pattern, the "traditional-healthy" pattern, and the "snack" pattern. The traditional-healthy pattern is characterized by a diet low in fat and high in carbohydrates as well as high intakes of fatty acids and minerals. The multivariate-adjusted odds ratio (OR) of ADHD for the highest tertile of the traditional-healthy pattern in comparison with the lowest tertile was 0.31 (95% CI: 0.12-0.79). The score of the snack pattern was positively associated with the risk of ADHD, but a significant association was observed only in the second tertile. A significant association between ADHD and the dietary pattern score was not found for the other two dietary patterns. In conclusion, the traditional-healthy dietary pattern was associated with lower odds having ADHD.

No Association Between Functional Polymorphisms in COMT and MTHFR and Schizophrenia Risk in Korean Population.

OBJECTIVES: Common genetic SNPs in two genes, encoding catechol-O-methyltransferase (COMT) and methylenetetrahydrofolate reductase (MTHFR), which are interconnected with COMT gene regulation, have been reported to contribute to schizophrenia risk. In this study, we evaluated the association between functional polymorphisms in COMT and MTHFR and schizophrenia risk with a case-control study in a Korean population. METHODS: We performed a case-control study by genotyping analysis using 360 cases and 348 controls in Korean subjects to determine the association between functional polymorphisms in COMT and MTHFR and schizophrenia risk. RESULTS: Four functional SNPs in COMT (Val158Met and rs165599) and MTHFR (C677T and A1298C) were genotyped by primer extension assay. None of the genotype distributions for the four SNPs was significantly different between cases and controls. Stratified analysis did not show any significant gender difference for any polymorphism. In addition, we found no evidence of a gene-gene interaction in the analysis of combined genotypes. CONCLUSION: Our results suggest no significant association between the selected functional polymorphisms of COMT or MTHFR in Korean schizophrenia subjects. However, further studies are required to confirm our findings in a larger number of subjects.

SCL-90-R and 16PF profiles of senior high school students with excessive internet use.

OBJECTIVE: To investigate the psychiatric symptomatology and personality characteristics of Korean senior high school students considered to use the Internet to excess. METHOD: We administered a questionnaire packet to students that included 4 measures. These measures included a questionnaire on Internet use patterns during the previous month, the Internet Addiction Test (IAT), the Symptom Checklist-90-R (SCL-90-R), and the Sixteen Personality Factor Questionnaire (16PF). A total of 328 students, aged 15 to 19 years, participated in the study. RESULTS: Students were divided into 4 Internet user groups according to their IAT total scores: nonusers (n = 59, 18.0%), minimal users (n = 155, 47.3%), moderate users (n = 98, 29.9%), and excessive users (n = 16, 4.9%). The SCL-90-R showed that the excessive users group, when compared with the other groups in this study, reported the highest levels of symptomatology. The 16PF also revealed that excessive users were easily affected by feeling, emotionally less stable, imaginative, absorbed in thought, self-sufficient, experimenting, and preferred their own decisions. CONCLUSIONS: This study suggests that senior high school students who use the Internet to excess report and subsequently exhibit significantly more psychiatric symptoms than students who use the Internet less frequently. In addition, excessive users appear to have a distinctive personality profile when compared with nonusers, minimal, and moderate users.