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

OBJECTIVES: Continuous positive airway pressure (CPAP) is effective in the treatment of obstructive sleep apnea syndrome (OSAS), but the major limitation of CPAP may be poor compliance. The aims of the study were to investigate the compliance and side effects of CPAP, and to evaluate the efficacy of CPAP in patients with OSAS. METHODS: This study enrolled 106 patients with OSAS who took the CPAP treatment. The severity of daytime sleepiness was measured using Epworth Sleepiness Scale (ESS), and sleep quality and depressive symptoms were assessed by Pittsburgh Sleep Quality Index (PSQI) and Beck Depression Inventory (BDI), respectively. RESULTS: During 29 months of the study period, 41.5% of patients were using CPAP and 38.7% of patients stopped using it. Compared to non-compliant patients, compliant patients had a higher PSQI score and obstructive apnea index. Among non-compliant patients, 51.2% of them stopped using CPAP within 1months. 85.7% of non-compliant patients were discomforted by the CPAP, but much more nasopharyngeal symptoms were reported in the compliant group. ESS (p<0.01), PSQI (p<0.01) and BMI (p<0.01) were reduced significantly after CPAP treatment but not BDI (p=0.86). CONCLUSIONS: We concluded that CPAP can reduce the daytime sleepiness, nocturnal sleep disturbance, and body mass index. To increase the compliance of CPAP, we suggested that some education and support is needed at the early stage of the CPAP treatment.
Apnea ; Body Mass Index ; Compliance* ; Continuous Positive Airway Pressure ; Depression ; Education ; Humans ; Sleep Apnea, Obstructive*

Obstructive sleep apnea (OSA) syndrome disrupts normal sleep. However, there were few studies to evaluate the asymmetric distribution, the one of the important factors of normal sleep in OSA subjects. We hypothesized that asymmetry would be broken in OSA patients. 49 male subjects with the complaint of heavy snoring were studied with polysomnography. We divided them into two groups based on the apnea-hypopnea index (AHI) fifteen: 13 simple snoring group (SSN, average AHI 5.9+/-4.4) and 32 OSA group (average AHI 47.3+/-23.9). We compared split sleep variables between the first half and the second half of sleep within each group with paired t-test for the evaluation of asymmetry. Changes of sleep architecture of OSA were higher stage 1 sleep% (S1), total arousal index (TAI), AHI, and mean heart rate (HR) and lower stage 2 sleep% (S2), REM sleep%, and mean arterial O2 saturation (SaO2) than SSN subjects. SWS and wake time after sleep onset (WASO) were not different between two groups. In split-night analysis, OSA subjects showed higher S2, slow wave sleep% (SWS), spontaneous arousal index (SAI), and mean HR in the first half, and higher REM sleep% and mean SaO2 in the second half. Those were same pattern as in SSN subjects. Mean apnea duration and longest apnea duration were higher in the second half only in the OSA. No differences of AHI, ODI, WASO, and S1 were found between the first and the second half of sleep in both groups. TAI was higher in the first half only in the SSN. SWS and WASO seemed to be influenced sensitively by simple snoring as well as OSA. Unlike our hypothesis, asymmetric distributions of major sleep architecture variables were preserved in OSA group. Losing asymmetry of TAI might be related to pathophysiology of OSA. We need more studies that include large number of subjects in the future.
Apnea ; Arousal ; Heart Rate ; Humans ; Male ; Polysomnography ; Sleep Apnea, Obstructive* ; Snoring

Obesity hypoventilation syndrome (OHS) is characterized by severe obesity, excessive daytime sleepiness, hypoxemia and hypercapnea. Because OHS mimics pulmonary hypertension or cor pulmonale, clinicians should recognize and treat this syndrome appropriately. A 58-year-old female visited the emergency room because of dyspnea. She was obese and had kyphoscoliosis. The patient also experienced snoring, recurrent choking during sleep and daytime hypersomnolence which worsened after gaining weight in the recent year. The arterial blood gas analysis showed she experienced hypoxemia and hypercapnea not only during nighttime but also daytime. We suspected OHS and the patient underwent polysomnography to confirm whether obstructive sleep apnea was present. During the polysomnography test, sleep obstructive apnea was observed and apnea-hypopnea index was 9.2/hr. The patient was treated with bilevel positive airway pressure therapy (BiPAP). After BiPAP for 4 days, hypoxemia and hypercapnia were resolved and she is currently well without BiPAP. We report a case successfully treated with clinical improvement by presuming OHS early in a patient who had typical OHS symptoms, even while having other conditions which could cause hypoventilation.
Airway Obstruction ; Anoxia ; Apnea ; Blood Gas Analysis ; Disorders of Excessive Somnolence ; Dyspnea ; Emergency Service, Hospital ; Female ; Humans ; Hypercapnia ; Hypertension, Pulmonary ; Hypoventilation ; Middle Aged ; Obesity Hypoventilation Syndrome* ; Obesity, Morbid ; Polysomnography ; Pulmonary Heart Disease ; Sleep Apnea, Obstructive ; Snoring

OBJECTIVES: The pathophysiology of restless legs syndrome (RLS) has not been fully elucidated. Oxidative stress might play a role in the development of RLS and other antipsychotic-induced side effects such as tardive dyskinesia. In the present study, we investigated whether the glutathione S-transferase (GST) gene polymorphisms are associated with antipsychotic-induced RLS in schizophrenia. METHODS: We assessed antipsychotic-induced RLS symptoms in 190 Korean schizophrenic patients using the diagnostic criteria of the International Restless Legs Syndrome Study Group. The GST-M1, GST-T1 and GST-P1 loci were analyzed using PCR-based methods. RESULTS: We divided the subjects into 2 groups: those with RLS symptoms (n = 96) and those without RLS symptoms (n = 94). There were no significant differences in the distributions of the GST-M1 genotypes (chi2 = 3.56, p = 0.059), GST-T1 (chi2 = 0.51, p = 0.476) and GST-P1 (chi2 = 0.57, p = 0.821) between the 2 groups. Comparison of the RLS score among genotypes of the GST-M1 (t = -1.54, p = 0.125), GST-T1 (t = -0.02, p = 0.985) and GST-P1 (F = 0.58, p = 0.560) revealed no significant difference. CONCLUSION: These data suggest that GST gene polymorphisms do not confer increased susceptibility to RLS symptoms in schizophrenic patients. Future studies are necessary to evaluate the possible influences of other candidate genes involved in the reactive oxygen species system.
Antipsychotic Agents ; Genotype ; Glutathione Transferase* ; Humans ; Movement Disorders ; Oxidative Stress ; Reactive Oxygen Species ; Restless Legs Syndrome* ; Schizophrenia