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

INTRODUCTION: Although it is well known that medical students are not getting an adequate amount of sleep, there have been only a few studies on the sleep patterns of medical students and the related factors. Therefore, the present study aimed to investigate the medical students' sleep patterns and the related factors. METHODS: A questionnaire package was administered to the 1st to 4th year medical students at one medical school. It consisted of questions asking about their lifestyles as well as Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), global assessment of recent stress scale (GASS), the center for epidemiologic studies-depression scale (CES-D), and Moudsley obsessive-compulsive inventory (MOCI). A total of 352 students (206 males and 146 females) responded to the survey and the result was analyzed using the independent t-test, the chi-square test, the paired t-test, Pearson's correlation and ANOVA. p-values of less than 0.05 were considered statistically significant in analyses. RESULTS: The weekend bedtime was significantly delayed (0 : 49 on weekday ; 1 : 34 on weekend ; t=-5.23, p<0.001), the weekend rise time was delayed (6 : 58 on weekday ; 9 : 30 on weekend ; t=-24.48, p<0.001) and the total sleep time was increased on weekends (5 : 36 on weekday ; 7 : 39 on weekend ; t=15.94, p<0.001). The PSQI score of all subjects was 6.43+/-2.64. PSQI was positively correlated with ESS (r=0.383, p<0.001), GASS (r=0.326, p<0.001), CES-D (r=0.393, p<0.001), and MOCI (r=0.247, p<0.001), but not with GPA (r=0.072, p=0.228. The more senior students had lower PSQI, GASS, CES-D, and MOCI score (p<0.05). CONCLUSION: Medical students were experiencing a lack of sleep during weekdays as they have a later bedtime and earlier rise time, and consequently had more hours of sleep on weekends. Overall, the medical students were experiencing poor sleep quality and sleep deprivation. Poor sleep quality is associated with psychological problems (daytime sleepiness, stress, depression, and obsessive tendency).
Depression ; Humans ; Life Style ; Male ; Surveys and Questionnaires ; Schools, Medical ; Sleep Deprivation ; Students, Medical*

OBJECTIVES: Several evidence has been suggested that the circadian gene variants contribute to the pathogenesis of seasonal affective disorder. In this study, we aimed to investigate the polymorphism in RORA (Retinoid-related orphan receptor A) gene in relation to seasonal variations among healthy young adults in Seoul, Korea. METHODS: A total of 507 young healthy adult subjects were recruited by advertisement. Seasonal variations were assessed by the Seasonality Pattern Assessment Questionnaire (SPAQ). Single-nucleotide polymorphism in the RORA rs11071547 gene was genotyped by PCR in 507 individuals. Considering summer type as confounding factor, we conducted analysis 478 subjects except 29 subjects of summer type. The Chi-square test was conducted to compare differences between groups of seasonals and non-seasonals. Association between genotypes and Global Seasonality Score (GSS) were tested using ANCOVA (Analysis of covariance). RESULTS: In this sample, the prevalence of SAD was 12.1% (winter type 9.3%, summer type 2.8%). There is no significant difference in genotyping distribution of RORA rs11071547 between groups of seasonals and non-seasonals. Global seasonality score (GSS) and scores of all subscales except body weight and appetite were not significantly different between the group with C allele homozygote and the group with T allele homozygote and heterozygote (p-value 0.138). Scores of body weight and appetite were significantly higher in group with C allele homozygotes. CONCLUSION: These results suggest that RORA gene polymorphism play a role in seasonal variations in appetite and body weight and is associated with susceptibility to seasonal affective disorder in some degree in the population studied.
Adult ; Alleles ; Appetite ; Body Weight ; Child ; Child, Orphaned ; Genotype ; Heterozygote ; Homozygote ; Humans ; Korea ; Polymerase Chain Reaction ; Prevalence ; Surveys and Questionnaires ; Seasonal Affective Disorder ; Seasons* ; Seoul ; Young Adult

Alcohol has been used as sedatives historically. The effect of alcohol on sleep is different according to its dose, timing of ingestion, and drinking frequency. Sleep problems may play a role in the development and course of alcohol-related disorders. Insomnia in alcohol-dependent patients is common and early treatment of insomnia may reduce the rate of relapse. Sleep apnea, restless legs syndrome, periodic limbs movement disorder, and altered circadian rhythm may be more frequent in this patients. Management of sleep and alcohol problems is important in treating alcohol-related disorder and sleep disorders, respectively.
Alcohol-Related Disorders ; Circadian Rhythm ; Drinking ; Eating ; Extremities ; Humans ; Hypnotics and Sedatives ; Movement Disorders ; Recurrence ; Restless Legs Syndrome ; Sleep Apnea Syndromes ; Sleep Wake Disorders ; Sleep Initiation and Maintenance Disorders

Autism Spectrum Disorder (ASD) is characterized by persistent deficits in social communication and restricted, repetitive patterns of behavior and interest. Sleep problems are not uncommon in children with autism spectrum disorders. Symptoms of insomnia are the most frequent sleep problems in individuals with ASD. Sleep problems can cause significant difficulties in the daily life of children with ASD and their families. Genetic factor, deregulations of melatonin synthesis, extraneous environmental stimuli and psychiatric and medical conditions may cause sleep problems. The first line treatment of sleep problems in ASD includes managements for potential contributing factors and parent education about sleep hygiene care for child and behavioral therapy. Supplementation with melatonin may be effective before considering other medications, such as risperidone, clonidine, and mirtazapine.
Autistic Disorder* ; Child ; Autism Spectrum Disorder* ; Clonidine ; Education ; Genetics ; Humans ; Hygiene ; Melatonin ; Parents ; Risperidone ; Sleep Initiation and Maintenance Disorders

Narcolepsy is a sleep disorder, which is characterized by excessive daytime sleepiness (EDS) that is typically associated with cataplexy, sleep fragmentation and other REM sleep-related phenomenon such as sleep paralysis and hypnagogic hallucination. Narcoleptic symptoms can be developed from various medical or neurological disorders. A 17-year-old male patient admitted for the evaluation of EDS which started three-month ago. He slept more than 18 hours a day with cataplexy and hypnagogic hallucination. He was obese with body mass index (BMI) of 30.4 kg/m2. After admission he was newly diagnosed to the thyrotoxicosis. T3 391.2 ng/dL (60-181), free T4 4.38 ng/dL (0.89-1.76), TSH <0.01 microIU/mL (0.35-5.5) were measured. His pulse rate ranged 70-90 beats per minute and blood pressure ranged 150/100-120/70 mmHg. Polysomnography revealed many fragmentations in sleep with many positional changes (81 times/h). Sleep onset latency was 33.5 min, sleep efficiency was 47.9%, and REM latency from sleep onset was delayed to 153.6 min. REM sleep percent was increased to 27.1%. Periodic limb movement index was 13.4/h. In the multiple sleep latency test (MSLT), average sleep latency was 0.4 min and there were noted 3 SOREMPs (Sleep Onset REM sleep period) on 5 trials. We couldn't discriminate the obvious sleep-wake pattern in the actigraph and his HLA DQB1 *0602 type was negative. His thyroid function improved following treatment with methimazole and propranolol. Vital sign maintained within normal range. Cataplexy was controlled with venlafaxine 75 mg. Subjective night sleep continuity and PLMS were improved with clonazepam 0.5 mg, but the EDS were partially improved with modafinil 200-400 mg. Thyrotoxicosis might give confounding role when we were evaluating the EDS, though sleep fragmentation was one of the major symptoms of narcolepsy, but enormous amount of it made us think of the influence of thyroid hormone. The loss of sleep-wake cycle, limited improvement of EDS to the stimulant treatment, and the cataplexy not supported by HLA DQB1 *0602 should be answered further. We still should rule out idiopathic hypersomnia and measuring CSF hypocretin level would be helpful.
Adolescent ; Benzhydryl Compounds ; Blood Pressure ; Body Mass Index ; Cataplexy ; Clonazepam ; Cyclohexanols ; Extremities ; Hallucinations ; Heart Rate ; HLA-DQ beta-Chains ; Humans ; Hypersomnolence, Idiopathic ; Intracellular Signaling Peptides and Proteins ; Male ; Methimazole ; Narcolepsy ; Nervous System Diseases ; Neuropeptides ; Polysomnography ; Propranolol ; Reference Values ; Sleep Deprivation ; Sleep Paralysis ; Sleep, REM ; Thyroid Gland ; Thyrotoxicosis ; Vital Signs ; Orexins ; Venlafaxine Hydrochloride

OBJECTIVE: Diurnal preference is an attribute reflecting whether people are alert and preferring to be active either early or late in the day. It also referred to as chronotype or morningness-eveningness trait. The PER3 genes have been known to influence diurnal preference. In this study, we have investigated the associations between the PER3 gene polymorphisms and diurnal preference in a healthy young population, controlling for the social and environmental confounding factors. METHODS: The participants in this experiment included 299 unrelated medical college students (M=191, F=108), with a mean age of 22.9 years. Diurnal preference was measured by a single administration of the 13-item Composite Scale for Morningness (CSM). Genotyping of the PER3 VNTR (rs57875989) was performed using polymerase chain reaction. A two-tailed alpha of 0.05 was chosen. RESULTS: The mean+/-SD score on the CSM scale for all subjects was 31.90+/-6.39. There was no significant difference in total CSM score between gender groups, although females showed a trend towards higher morningness score. Although PER3 5R/5R showed the tendency towards high CSM scores, there were no significant differences on CSM scores among genotypes and allele status of PER3 VNTR (rs57875989). CONCLUSIONS: We could not confirm that the PER3 VNTR is associated with diurnal preference in a Korean healthy young population. The future studies need to investigate the association between diurnal preference and other polymorphisms of PER3 gene in larger sample of Korean young healthy population.
Alleles ; Female ; Genotype ; Humans ; Polymerase Chain Reaction

OBJECTIVES: The purposes of this study were to estimate the effect of mandibular advancement device (MAD) and to evaluate the influence of the advancement amount of mandible in the application of MAD for obstructive sleep apnea (OSA) patients. METHODS: From the patients who were diagnosed as OSA by polysomnographic study at Seoul National University Bundang Hospital from January 2007 to February 2009, the patients who chose MAD as treatment option were included in this study. All the patients' data including clinical records and polysomnographic studies (both pre- and post-treatment) were reviewed and analyzed. RESULTS: Successful results were obtained in 65 patients of 86 patients (75.6%). In the follow-up period, mild discomfort of anterior teeth or temporomandibular joint (TMJ) were described in 28 patients, especially in the cases the amount of mandibular advancement were more than 7.0 mm. There was no direct relationship between the amount of mandibular advancement and clinical outcome. CONCLUSION: MAD was effective treatment option for the OSA patients regardless of severity. For the prevention of potential dental complications, the amount of mandibular advancement should be considered at the time of MAD treatment.
Adenine Nucleotides ; Follow-Up Studies ; Humans ; Mandible ; Mandibular Advancement ; Mycophenolic Acid ; Sleep Apnea, Obstructive ; Temporomandibular Joint ; Tooth

OBJECTIVES: REM sleep behavior disorder (RBD) has received little attention in epidemiologic studies. This study aimed to determine the prevalence of probable REM sleep behavior disorder (pRBD) in the elderly population and its clinical features. METHODS: A random sample of 1,588 was selected from a roster of 14,050 elderly population living in Osan city. The subjects were asked to fill out the REM sleep behavior disorder screening questionnaire (RBDSQ). Subjects whose score were 5 or higher on RBDSQ underwent a diagnostic phase of person-to-person assessment by experts in RBD. RESULTS: Among 1,588 subjects, 886 elderly subjects participated in the screening phase and 123 subjects were assessed in the diagnostic phase. Eleven subjects were diagnosed as having pRBD, so prevalence was 1.5% (95% CI=0.70-2.30%). The frequency of depression and cognitive decline was significantly increased in patients with pRBD compared to subjects without pRBD, and there was no difference in sleep disturbances between two groups. CONCLUSIONS: Probable REM sleep behavior disorder is not rare in the elderly but frequently under-recognized. More attention should be paid to evaluation and treatment of RBD.
Aged ; Depression ; Epidemiologic Studies ; Humans ; Mass Screening ; Prevalence ; Surveys and Questionnaires ; REM Sleep Behavior Disorder ; Sleep, REM