OBJECTIVES: "Internet-addiction" came into common use not only in clinical setting but also in everyday life. But, pathophysiology and diagnostic criteria of the internet addiction remain unknown. Because adolescents are in developing period, they might be vulnerable to the internet addiction, depression and sleep-related problem. The objectives of this study were to investigate the characteristics of internet addiction and its association with sleep pattern and depression in Korean adolescence. METHODS: Subjects were 799 middle and high school students in Seoul, Korea. We administered a self-reported questionnaire including socio-demographic data, Korean versions of Young's Internet Addiction Scale (YIAS), Pittsburgh Sleep Quality Index (PSQI), the Center for Epidemiologic Studies for Depression Scale (CES-D) and questions about internet using patterns. Data of 696 subjects were included in analysis. Chi-square tests were used to analyze proportional differences, and ANOVA with post-hoc tests were used to analyze differences among groups. Partial correlation analyses were performed to analyze the correlation of internet addiction with other variables (two-tailed, p<0.05). RESULTS: Of the 696 participants (grade 2 of middle school;M2 135 vs. grade 1 of high school;H1 238 vs. grade 2 of high school;H2 323), 2.0% (n=14) were internet-addicted (IA), 27.7% (n=193) were over-using (OU) and 70.3% (n=489) were not-addicted (NA). The mean scores of YIAS, PSQI and CES-D scores were 35.24+/-12.78, 5.53+/-3.04 and 16.72+/-8.69, respectively. In higher grade students, average total sleep time was shorter (M2 426.20+/-67.68 min. vs. H1 380.47+/-62.57 min. vs. H2 354.67+/-73.37 min., F=51.909, p<0.001), and PSQI (4.69+/-3.14 vs. 5.42+/-3.15 vs. 5.97+/-2.83, F=8.871, p<0.001) CES-D (13.53+/-8.37 vs. 16.96+/-8.24 vs. 17.87+/-8.84, F=12.373, p<0.001) scores were higher than those of lower grade students. Comparing variables among IA, OU and NA groups, computer using time not for study (96.36+/-63.31 min. vs. 134.92+/-86.79 min. vs. 213.57+/-136.87 min., F=34.287, p<0.001) and portable device using time not for study (84.22+/-79.11 min. vs. 96.97+/-91.89 min. vs. 152.31+/- 93.64 min., F=5.400, p=0.005) were different among groups. PSQI (5.26+/-2.97 vs. 6.08+/-2.97 vs. 7.50+/-4.41, F=8.218, p<0.001) and CES-D scores (15.40+/-8.08 vs. 19.05+/-8.42 vs. 30.43+/-13.69, F=32.692, p<0.001) were also different among groups. YIAS score were correlated with computer using time not for study (r=0.356, p<0.001) and portable device using time not for study (r=0.136, p<0.001). PSQI score (r=0.237, p<0.001) and CES-D score (r=0.332, p<0.001). YIAS score and PSQI score (r=0.131, p=0.001), YIAS and CES-D score (r=0.265, p<0.001), PSQI score and CES-D score (r=0.357, p<0.001) were correlated each other. CONCLUSION: These results suggested that adolescents' internet-addiction was correlated with not only computer and portable device using time not for study but also depression and sleep-related problems. We should pay attention to depression and sleep-related problems, when evaluating internet-addiction in adolescents.
Adolescent ; Depression ; Epidemiologic Studies ; Humans ; Internet ; Korea ; Porphyrins ; Surveys and Questionnaires

OBJECTIVES: Deficit schizophrenia (DS) constitutes a disease separate from non-deficit schizophrenia (NDS). The aim of the current study was to compare the quantitative EEG and low resolution electromagnetic tomography (LORETA) imaging between DS and NDS. METHODS: This study was performed by 32 channels EEG for 42 schizophrenia patients who we categorized into DS and NDS using proxy instrument deficit syndrome (PDS). We performed the absolute power spectral analyses for delta, theta, alpha, low beta and high beta activities. We compared power spectrum between two groups using Independent t-test. Partial correlation test was performed with clinical parameters. Standardized LORETA (sLORETA) was used for comparison of cortical activity, and statistical nonparametric mapping (SnPM) was applied for the statistical analysis. RESULTS: DS showed significantly increased delta and theta absolute power in fontal and parietal region compared with NDS (p<0.05). Power spectrum showed significant correlation with 'anergia' and 'hostility/suspiciousness' subscale of brief psychiatric rating scale (BPRS)(p<0.05). sLORETA found out the source region (anterior cingulate cortex/limbic part) that delta activity was significantly increased in DS (p=0.042). CONCLUSIONS: DS showed different cortical activity compared with NDS. Our results may suggest QEEG and LORETA could be the marker in differentiating between DS and NDS.
Brief Psychiatric Rating Scale ; Electroencephalography ; Humans ; Magnets ; Naphthalenesulfonates ; Proxy ; Schizophrenia

OBJECTIVES: Ginseng has a long history of being used in insomnia treatment and there is some evidence from animal studies of its sleep-enhancing property. From this, it can be assumed that ginseng has sleep-promoting effect in humans. The purpose of this study was to investigate the effect of Korean red ginseng on change of sleep architecture in humans. METHODS: A total of 20 healthy young males with regular sleep and wake habits and without any psychiatric nor cognitive problems were selected based on review of sleep questionnaires and sleep diaries they completed followed by an interview with a board-certified psychiatrist. The subjects were randomly assigned to red ginseng or placebo for 2 weeks of trial. The total daily dose of ginseng was 4,500 mg. The polysomnographic recordings were made at baseline and at 2 weeks after. The effects of red ginseng and placebo on sleep were assessed by comparing the changes in polysomnographic variables between the two groups. RESULTS: A total of 15 subjects, 8 from red ginseng group and 7 from placebo group, were included to undergo polysomnographic procedures. The red ginseng group showed tendencies to increase stage 3 sleep (p=0.087) and to decrease stage 2 sleep (p=0.071) from the baseline compared with the placebo group. CONCLUSION: Korean red ginseng tends to increase deep sleep and decrease shallow sleep. Our result is in line, at least in part, with previous findings that Korean red ginseng increased total and NREM sleep in rats. Further studies with higher ginseng dosage, larger sample size and longer trial duration should be conducted to confirm the sleep stabilizing and balancing effects of Korean red ginseng.
Animals ; Humans ; Male ; Panax ; Polysomnography ; Psychiatry ; Surveys and Questionnaires ; Rats ; Sample Size ; Sleep Initiation and Maintenance Disorders

The cyclic alternating pattern (CAP) is a periodic EEG activity in NREM sleep, characterized by sequences of transient electrocortical events that are distinct from background EEG activities. A CAP cycle consists of two periodic EEG features, phase A and subsequent phase B whose durations are 2-60 s. At least two consecutive CAP cycles are required to define a CAP sequence. The CAP phase A is a phasic EEG event, such as delta bursts, vertex sharp transients, K-complex sequences, polyphasic bursts, K-alpha, intermittent alpha, and arousals. Phase B is repetitive periods of background EEG activity. The absence of CAP more than 60 seconds or an isolated phase A is classified as non-CAP. Phase A activities can be classified into three subtypes (A1, A2, and A3), based on the amounts of high-voltage slow waves (EEG synchrony) and low-amplitude fast rhythms (EEG desynchrony). CAP rate, the percentage of CAP durations in NREM sleep is considered to be a physiologic marker of the NREM sleep instability. In insomnia, the frequent discrepancy between self-reports and polysomnographic findings could be attributed to subtle abnormalities in the sleep tracing, which are overlooked by the conventional scoring methods. The conventional scoring scheme has superiority in analysis of macrostructure of sleep but shows limited power in finding arousals and transient EEG events that are major component of microstructure of sleep. But, it has recently been found that a significant correlation exists between CAP rate and the subjective estimates of the sleep quality in insomniacs and sleep-improving treatments often reduce the amount of CAP. Thus, the extension of conventional sleep measures with the new CAP variables, which appear to be the more sensitive to sleep disturbance, may improve our knowledge on the diagnosis and management of insomnia.
Arousal ; Electroencephalography ; Research Design ; Sleep Initiation and Maintenance Disorders

Obstructive sleep apnea syndrome is associated with significant cardiovascular morbidity and increased mortality. However, it was controversial whether obstructive sleep apnea syndrome could cause pulmonary hypertension. The controversy was resolved by several studies that have shown pulmonary hypertension in 20% to 40% of patients with obstructive sleep apnea syndrome without underlying other cardiopulmonary diseases and reductions in pulmonary arterial pressure in patients with obstructive sleep apnea syndrome after treatment with nocturnal continuous positive airway pressure. Recent studies provide strong evidence for endothelial dysfunction in obstructive sleep apnea syndrome and pulmonary hypertension. Endothelin-1 is a 21 amino acid peptide with diverse biologic activity such as highly potent vasoconstrictor and mitogen regulator that may play a key role in obstructive sleep apnea syndrome and pulmonary hypertension. Continuous positive airway pressure therapy is moderately effective in reducing pulmonary arterial pressure. Further researches are needed to assess the therapeutic efficacy of pharmacologic therapy with agents that inhibit the action of endothelin-1 in obstructive sleep apnea syndrome patients with pulmonary hypertension.
Arterial Pressure ; Continuous Positive Airway Pressure ; Endothelin-1 ; Humans ; Hypertension ; Hypertension, Pulmonary ; Sleep Apnea, Obstructive

Narcolepsy is a central neurologic system disease. It begins early in life with disabling symptoms including excessive daytime sleepiness, cataplexy, sleep paralysis, hypnagogic hallucination and nocturnal sleep fragmentation. Patient with typical symptoms of narcolepsy is diagnosed by objective data from nocturnal polysomnography and multiple sleep latency tests. Narcolepsy is controlled with various medications. Nowadays, modafinil with favorable side effects profiles compared with traditional stimulant is mainly used. Gamma hydroxyl butyrate is effective in cataplexy. Cataplexy is also controlled with antidepressant such as Venlafaxine, SSRI, and TCA. As the knowledge of pathophysiology of narcolepsy expands, new treatment including immunological method, application of hypocretin and histamine systems have been tried.
Benzhydryl Compounds ; Butyrates ; Cataplexy ; Cyclohexanols ; Disorders of Excessive Somnolence ; Hallucinations ; Histamine ; Humans ; Intracellular Signaling Peptides and Proteins ; Narcolepsy ; Neuropeptides ; Polysomnography ; Sleep Deprivation ; Sleep Paralysis ; Orexins ; Venlafaxine Hydrochloride

INTRODUCTION: Excessive daytime sleepiness and cataplexy are key features of narcolepsy. Modafinil is psychostimulant used in the treatment of narcolepsy. In this study, we evaluated effects of modafinil on nocturnal sleep structure and sleep latency in multiple sleep latency test and clinical features. METHODS: Twelve narcoleptic patients (7 male, age: 22.9 +/- 2.6 yrs) were participated in the study. All of them had done nocturnal polysomnography (nPSG), multiple sleep latency test (MSLT), clinical symptoms scales and have repeated same procedure after taking 200 mg of modafinil. We have done linear mixed model analysis to describe effects of group, medication and nap time on these measures. RESULTS: Modafinil did not affect clinical scales except PSQI which had been reduced after medication. In this study, Modafinil reduced total sleep time, sleep efficiency and increased wake after sleep onset and percent of arousal during sleep in nocturnal polysomnography and prolonged mean sleep latency in multiple sleep latency tests in both group. DISCUSSION: Modafinil has stimulant effect of central nervous system but its effect on night sleep is less than other psychostimulants such as methylphenidate. We ascertained that modafinil affected total sleep time, sleep efficiency and percent of wake during sleep but did not effect on sleep structure. Modafinil was effective in the management of day time sleepiness. Modafinil can enhance alertness of control group without day time sleepiness.
Arousal ; Cataplexy ; Central Nervous System ; Humans ; Male ; Methylphenidate ; Narcolepsy* ; Polysomnography ; Weights and Measures

The objective of this study was to investigate the relationship between insomnia severity, depression, anxiety, and anxiety sensitivity and to find out the explanatory variables that account for the insomnia severity among depression, anxiety, and anxiety sensitivity in general population. 95 mentally healthy volunteers who visit health promotion center of Kangbuk Samsung hospital for their regular medical examination were requested to complete Athens Insomnia Scale, Beck Depression Inventory, State-Trait Anxiety Inventory, and Anxiety Sensitivity Index. Association between total scores of Athens Insomnia scale and other variables (total scores of Beck Depression Inventory excluded item 16, total scores of State Anxiety, total scores of Trait Anxiety, and total scores of Anxiety Sensitivity Scale) was assessed individually with partial correlations adjusted by age and then together using multiple regression analysis. The total scores of Athens Insomnia Scale were significantly associated with total scores of Beck Depression Inventory excluded item 16(r = 0.541, p<0.001), total scores of Trait Anxiety(r = 0.642, p<0.001), total scores of State Anxiety(r = 0.267, p<0.05), and total scores of Anxiety Sensitivity Index(r = 0.312, p<0.01). Total scores of trait anxiety showed the highest correlation with the total scores of Athens Insomnia Scale and was the significant predictor to total scores of Athens Insomnia Scale among the other predictor variables (p<0.001). These results show that insomnia severity is positively correlated with depression, anxiety, and anxiety sensitivity. The correlation was strongest with trait anxiety. In addition, our results suggest that trait anxiety is associated with insomnia severity in general populations.
Anxiety* ; Depression* ; Health Promotion ; Healthy Volunteers ; Sleep Initiation and Maintenance Disorders*

OBJECTIVES: Previous studies have reported an association between circadian preference and personality. Defense mechanism is unconscious ego process which deals with an individual's anxiety and is closely associated with one's personality. Our aim is to investigate the association between defense mechanism and circadian preference in medical students. METHODS: One hundred forty eight medical students (70 males, 78 females), aged 22 to 30, answered the Beck Depression Inventory-II, Morningness-eveningness Questionnaire, and Korean version of Defense Style Questinnaire. RESULTS: Consumption (beta=-0.262, p=0.001) and being a male (beta=0.175, p=0.031) were significant positive predictors of eveningness, while sublimation (beta=0.185, p=0.023) was a significant negative predictor of eveningness. CONCLUSION: Our study showed a relationship between specific defense mechanisms (i.e., consumption and sublimation) and eveningness in medical students, but it did not address whether the relationship is a causal one.
Anxiety ; Defense Mechanisms ; Depression ; Ego ; Humans ; Male ; Surveys and Questionnaires ; Students, Medical* ; Sublimation*

OBJECTIVES: There are a lot of studies that analyze the interaction between the emotion of disgust and the functional brain images using fMRI and PET. But studies using sLORETA (standardized low resolution brain electromagnetic tomography) almost do not exist. The aim of this research is to explore the relationship of the emotion of disgust and the cortical activation using sLORETA analysis. METHODS: Forty five healthy young adults (27.1+/-2.6 years) participated in the study. While they were watching 4 neutral images and 4 disgusting images associated with mutilation selected from the international affective picture system (IAPS), participants' EEGs were taken for 30 seconds per one picture. Through these obtained EEG data, sLORETA analysis was performed to compare EEGs associated with neutral and negative images. RESULTS: During looking for visual disgusting stimulus, all participants reported unpleasantness, arousal and stress. In sLORETA analysis, the decrease of current density in theta wave was shown at left frontal superior gyrus (BA10) and middle gyrus (BA10, 11). This voxel cluster consists of a total of 11 voxels and the threshold of t value indicating statistically significant decreases in the current density (p<0.05) was -1.984. There were no differences between male and female in the degree of being disgusted by the stimuli. CONCLUSION: This finding may suggest that the activation of dorsolateral prefrontal cortex might be associated with regulating disgust emotion.
Arousal ; Brain ; Electroencephalography ; Female ; Humans ; Magnetic Resonance Imaging ; Magnets ; Male ; Prefrontal Cortex ; Young Adult