Predictors of Continuous Positive Airway Pressure Adherence and Comparison of Clinical Factors and Polysomnography Findings Between Compliant and Non-Compliant Korean Adults With Obstructive Sleep Apnea

OBJECTIVE

Continuous positive airway pressure (CPAP) is the preferred treatment for obstructive sleep apnea (OSA). However, compliance with CPAP therapy varies among studies, and studies on its predictors are insufficient in Korea. This study aimed to identify factors that predict compliance with CPAP therapy in patients with OSA.

METHODS

We retrospectively reviewed medical records, polysomnography (PSG) records, and self-report questionnaires of patients w ith OSA. Criteria for compliance was the use of CPAP devices for ≥4 h per night for ≥70% of the consecutive 30 nights (i.e., 21 days) during the first 3 months of treatment initiation. The patients were classified into two groups: compliant and non-compliant. Logistic regression analyses were performed to identify the clinical factors and PSG parameters associated with CPAP compliance.

RESULTS

Of the 188 participants, 80 were classified into the compliant group and 108 into the non-compliant group. The ratios of stage N1 (p=0.011) and health insurance coverage (p=0.007) were significantly associated with compliance with CPAP, with an explanatory power of 18.6% (R2=0.186, p<0.001).

CONCLUSION

Stage N1 ratio and health insurance coverage were significant predictors of CPAP compliance. It is necessary to confirm whether the relationship between a high stage N1 ratio and compliance can be reproduced in a larger sample and in individuals from other countries.

Low myelin-related values in the fornix and thalamus of 7 Tesla MRI of major depressive disorder patients

Introduction

Abnormalities in myelin are believed to be one of the important causes of major depressive disorder, and it is becoming important to more accurately quantify myelin in in vivo magnetic resonance imaging of major depressive disorder patients. We aimed to investigate the difference in myelin concentration in the white matter and subcortical areas using new quantitative myelin-related maps of high-resolution 7 Tesla (7 T) magnetic resonance imaging between patients with major depressive disorder and healthy controls.

Methods

Myelin-related comparisons of the white matter and nearby subcortical regions were conducted between healthy controls (n = 36) and patients with major depressive disorder (n = 34). Smoothed quantitative ratio (sq-Ratio) myelin-related maps were created using the multi-echo magnetization-prepared two rapid gradient echoes (ME-MP2RAGE) sequence of the T1 and T2* images of 7 T magnetic resonance imaging. Differences in the myelin-related values of the regions of interest between the two groups were analyzed using a two-sample t-test, and multiple comparison corrections were performed using the false discovery rate.

Results

The average sq-Ratio myelin-related values were 2.62% higher in the white matter and 2.26% higher in the subcortical regions of the healthy controls group than in the major depressive disorder group. In the group analysis of the healthy control and major depressive disorder groups, the sq-Ratio myelin-related values were significantly different in the fornix area of the white matter (false discovery rate-corrected p = 0.012). In addition, significant differences were observed in both the left (false discovery rate-corrected p = 0.04) and right thalamus (false discovery rate-corrected p = 0.040) among the subcortical regions.

Discussion

The average sq-ratio myelin-related value and sq-ratio myelin-related values in the fornix of the white matter and both thalami were higher in the healthy controls group than in the major depressive disorder group. We look forward to replicating our findings in other populations using larger sample sizes.

Significant association between increased risk of emergency department visits for psychiatric disorders and air pollutants in South Korea

BACKGROUND

The association between air pollutants and psychiatric disorders has been investigated in many countries. However, results for the association between air pollutants and emergency room (ER) visits for psychiatric disorders are inconsistent. Further, systematic large-scale studies relating to the same are lacking, especially in South Korea.

OBJECTIVE

We aimed to investigate the acute and short-term cumulative effect of air pollutants on ER visits for psychiatric disorders in South Korea.

METHODS

The data on nitrogen dioxide (NO2) and particulate matter (PM2.5 and PM10) and ER visits due to nine representative psychiatric disorders were collected from eight major cities in South Korea for three years. We estimated the relative risk (RR) at lag 0 and a cumulative 11-day RR by increasing a 10-unit for PM and 0.01-unit for NO2 using the Distributed Lag Nonlinear Model.

RESULTS

During the study period, a total of 79,092 ER visits for psychiatric disorders were identified and tested for association with NO2, PM2.5, and PM10. The RR at lag 0 of depression per 0.01-unit increase in NO2 was the highest (3.127; 95% confidence interval [CI] 2.933 to 3.332) among the psychiatric disorders. The RRs at lag 0 of anxiety disorders per 10-unit increase in PM2.5 (1.709; 95% CI 1.424 to 2.053) and PM10 (2.168; 95% CI 1.957 to 2.403) were the highest among the psychiatric disorders.

SIGNIFICANCE

Air pollutants increased ER visits for psychiatric disorders with the highest RR of depression due to NO2 and anxiety disorder due to PM2.5 and PM10. These results contribute evidence to the positive association between ambient exposure to air pollution and aggravation of psychiatric disorders, indicating air pollution may be a modifiable risk factor in mental health management.

IMPACT STATEMENT

We investigated the effect of air pollution on emergency room visits caused by major psychiatric disorders in prominent cities in South Korea. Using the Distributed Lag Nonlinear Model, an advanced analysis method, we calculated the acute effect and short-term cumulative effect. Air pollutants increased ER visits for psychiatric disorders with the highest relative risk of depression due to NO2 and anxiety disorder due to PM2.5 and PM10. These results reveal an association between ambient exposure to air pollution and aggravation of psychiatric disorders and suggest that air pollution may be a modifiable risk factor in mental health management.

Quantitative myelin-related maps from R1 and T2* ratio images using a single ME-MP2RAGE sequence in 7T MRI

Background: There still are limitations associated with quantifying myelin content using brain magnetic resonance imaging (MRI) despite several studies conducted on this subject. Therefore, this study aimed: (1) to propose a myelin-related mapping technique to obtain the quantitative R1/T2* (q-Ratio) that has the advantage of quick processing and less dependency on imaging parameters, (2) to validate this adapted q-Ratio method by comparing the quantitative myelin-related map with those acquired through an existing mapping method [T1-weighted/T2*-weighted (w-Ratio)], and (3) to determine the q-Ratio myelin-related values in the white and gray matter, and the relationship between the q-Ratio myelin-related value and cerebral volume size in regions of interest (ROIs) in a healthy population.

Methods: The multi-echo magnetization-prepared 2 rapid gradient echoes (ME-MP2RAGE) sequence was used in a 7 Tesla (7T) MRI for the acquisition of data regarding myelin content in 10 healthy participants. A correlation analysis was performed between myelin-related values obtained through the q-Ratio and w-Ratio methods. Additionally, myelin distribution was analyzed and compared in the white and gray matter, and the correlation between cerebral volume size and q-Ratio myelin-related value was analyzed in ROIs in the brain.

Results: The myelin-related maps acquired through the q-Ratio and w-Ratio methods were significantly correlated (p &lt; 0.001), but the q-Ratio myelin-related map was much clearer. Additionally, the cerebral volume size in the gray matter was 399.40% larger than that in the white matter, but the q-Ratio myelin-related value in the gray matter was 80.83% lower than that of the white matter. Furthermore, volume size was positively correlated with q-Ratio myelin-related values in the white matter (r = 0.509, p = 0.006) but not in the gray matter (r = -0.133, p = 0.402).

Conclusions: In this study, we validated using a q-Ratio myelin-related map that was acquired in one imaging sequence at 7T MRI. In addition, we found a significant correlation between ROI volume size and the q-Ratio myelin-related value in the white matter but not in the gray matter. It is expected that this technique could be applied to the study of various neuropsychiatric diseases related to demyelination in the future.

Association Between Subjective-Objective Discrepancy of Sleeping Time and Health-Related Quality of Life: A Community-Based Polysomnographic Study

OBJECTIVE

This study aimed to investigate the existence of a difference in quality of life (QOL) between individuals with and without significant subjective-objective discrepancy (SOD) in total sleep time (TST).

METHODS

From the Sleep Heart Health Study 2, 2540 individuals who had completed polysomnography, a morning sleep survey, and the 36-item Short-Form Health Survey (SF-36) were included in the analyses. The participants were classified as normoestimators (estimation of TST <±60 minutes), underestimators (underestimation of TST ≥60 minutes), or overestimators (overestimation of TST ≥60 minutes). The standardized SF-36 QOL scores were compared among the three groups. An adjusted partial correlation analysis was conducted between SOD and QOL.

RESULTS

Of the 2540 participants, 1617 (63.7%), 433 (17.0%), and 490 (19.3%) were assigned to the normoestimator, underestimator, and overestimator groups, respectively. The bodily pain and social functioning components of the SF-36 score were significantly lower in the underestimators than in the normoestimators, whereas the physical functioning component was significantly lower in the overestimators than in the normoestimators. The absolute value of SOD in the TST showed a significant negative correlation with the physical and mental components of the SF-36.

CONCLUSIONS

QOL was significantly better in the normoestimator than in the other groups and linearly correlated with the absolute value of SOD. This study suggests that a high prevalence of positive and negative sleep misperception in a community population can be a potential factor associated with poor QOL and potential comorbidities.

Mood and Sleep Status and Mental Disorders During Prolonged Winter-Over Residence in Two Korean Antarctic Stations

PURPOSE

Antarctica is a region with extreme climate, characterized by extreme cold and photoperiod. No research has been conducted on the mental health of Korean Antarctic dispatchers. The aim of this study was to investigate the status of mental illness and changes in mood and sleep among Korean crew members staying for a long-term period in the Antarctic station.

METHODS

From 2017 to 2020, crew members who were dispatched from South Korea to two Antarctic stations for a one-year period participated in this study. The crew were evaluated for mood and sleep status and mental illness through psychological tests and interviews by board-certified psychiatrists once before departure and twice during their stay in Antarctica. The incidence of mental illness was confirmed and changes in sleep and depression were analyzed.

RESULTS

A total of 88 participants were included in the final analysis, and 7 of them (8.0%) were diagnosed with mental disorders such as insomnia in early winter. The total Beck Depression Inventory (BDI) score increased significantly in the early winter period, and the total Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Inventory (PSQI) scores increased in both early and late winter. The difference in changes in mood and sleep symptoms before, during, and after dispatch between the two stations was not significant.

CONCLUSION

This is the first study to investigate the mental illness and mood and sleep status of Korean crews dispatched to Antarctica. In early winter, there were significant increases in mental illness and depressive symptoms, and a worsening of sleep status.

Decreased resting-state functional connectivity of the habenula-cerebellar in a major depressive disorder

BACKGROUND

In animal experiments, the habenula and septal nuclei are known as the key brain areas of depression. However, there are few magnetic resonance imaging (MRI) studies on the functional connectivity between these areas and the subcortical areas in humans with major depression. We aimed to investigate the difference in resting-state functional connectivity (RSFC) among the major regions of interest (ROI) in the subcortical areas, including both the habenula and septal nuclei.

METHODS

We performed the seed-to-voxel analysis to investigate the RSFC between both the habenula and septal nucleus, as well as other subcortical regions. Furthermore, ROI-to-ROI analysis was performed among the combinations of ROI pairs in the subcortical areas.

RESULTS

The seed-to-voxel analysis showed a lower RSFC between the left habenula and the cerebellum in major depressive disorder (MDD) than in healthy controls (HCs). As a result of ROI-to-ROI analysis in subcortical areas, a total of 31 pairs of FCs in the MDD group showed a lower RSFC than in the HCs group.

CONCLUSION

This study revealed a lower RSFC between the left habenula and cerebellum in patients with MDD and reduced RSFC among numerous subcortical areas. These new findings on the neural circuitry of MDD might contribute to an in-depth understanding of depression.

Thalamocortical functional connectivity in patients with insomnia using resting-state fMRI

BACKGROUND

Insomnia is a common disorder that affects a vast number of patients; the hyperarousal theory of insomnia postulates that patients with insomnia are physiologically activated not only at nighttime but also during the daytime. We aimed to investigate the differences in the resting-state functional connectivity (RSFC) of the thalamus with cortical areas between patients with insomnia disorder and healthy controls.

METHODS

All participants completed clinical questionnaires and underwent portable polysomnography and resting-state fMRI.

RESULTS

Patients in the insomnia group (n = 50) showed increased RSFC between the thalamus and right medial superior frontal area, bilateral middle temporal areas, left rectus and right parahippocampal areas compared with controls (n = 42) after controlling for age, sex and education level. Among the pairs that showed increased connectivity, several functional connections were negatively correlated with sleep efficiency, measured by polysomnography.Limitations: We used a small sample size.

CONCLUSION

We consider these results on increased thalamocortical hyperactivity in brain areas related to sensory functions as providing evidence for the hyperarousal theory of insomnia.

Relationship between the Spectral Power Density of Sleep Electroencephalography and Psychiatric Symptoms in Patients with Breathing-related Sleep Disorder

Objective

Patients with breathing-related sleep disorder (BRSD) often complain of psychiatric symptoms such as depression in addition to snoring, excessive sleepiness, and disturbed sleep. However, the relationship between psychiatric symptoms and severity of sleep apnea in BRSD is controversial. We conducted this study to investigate the relationship between psychiatric symptoms and sleep electroencephalography (EEG) findings in BRSD patients using spectral analysis.

Methods

All participants underwent polysomnography and evaluation using Symptom Checklist-90-Revised (SCL-90-R) scale. We analyzed the absolute spectral power density values of standard EEG frequency bands in the participants (n = 169) with BRSD during the non-rapid eye movement (NREM) sleep period. We performed correlation analysis between the domain scores of SCL-90-R scale and the absolute values of the EEG frequency bands.

Results

Significant positive correlation was observed between the absolute spectral power density values in the slow oscillation band and the degree of paranoid ideation (r = 0.226, p = 0.028) and depression (r = 0.216, p = 0.044) in SCL-90-R. The multiple linear regression model showed that higher paranoid ideation domain score (B = 0.007, p = 0.020), younger age (B = −0.011, p < 0.001), and female sex (B = 0.213, p = 0.004) were associated with higher slow oscillation power during NREM sleep.

Conclusion

The results of the present study suggested a relationship between sleep EEG and psychiatric symptoms in patients with BRSD. This relationship needs to be validated with further studies.

Reproducibility of automated habenula segmentation via deep learning in major depressive disorder and normal controls with 7 Tesla MRI

The habenula is one of the most important brain regions for investigating the etiology of psychiatric diseases such as major depressive disorder (MDD). However, the habenula is challenging to delineate with the naked human eye in brain imaging due to its low contrast and tiny size, and the manual segmentation results vary greatly depending on the observer. Therefore, there is a great need for automatic quantitative analytic methods of the habenula for psychiatric research purposes. Here we propose an automated segmentation and volume estimation method for the habenula in 7 Tesla magnetic resonance imaging based on a deep learning-based semantic segmentation network. The proposed method, using the data of 69 participants (33 patients with MDD and 36 normal controls), achieved an average precision, recall, and dice similarity coefficient of 0.869, 0.865, and 0.852, respectively, in the automated segmentation task. Moreover, the intra-class correlation coefficient reached 0.870 in the volume estimation task. This study demonstrates that this deep learning-based method can provide accurate and quantitative analytic results of the habenula. By providing rapid and quantitative information on the habenula, we expect our proposed method will aid future psychiatric disease studies.

Prediction Models for Obstructive Sleep Apnea in Korean Adults Using Machine Learning Techniques

This study aimed to investigate the applicability of machine learning to predict obstructive sleep apnea (OSA) among individuals with suspected OSA in South Korea. A total of 92 clinical variables for OSA were collected from 279 South Koreans (OSA, n = 213; no OSA, n = 66), from which seven major clinical indices were selected. The data were randomly divided into training data (OSA, n = 149; no OSA, n = 46) and test data (OSA, n = 64; no OSA, n = 20). Using the seven clinical indices, the OSA prediction models were trained using four types of machine learning models—logistic regression, support vector machine (SVM), random forest, and XGBoost (XGB)—and each model was validated using the test data. In the validation, the SVM showed the best OSA prediction result with a sensitivity, specificity, and area under curve (AUC) of 80.33%, 86.96%, and 0.87, respectively, while the XGB showed the lowest OSA prediction performance with a sensitivity, specificity, and AUC of 78.69%, 73.91%, and 0.80, respectively. The machine learning algorithms showed high OSA prediction performance using data from South Koreans with suspected OSA. Hence, machine learning will be helpful in clinical applications for OSA prediction in the Korean population.

Clinical Usefulness of Amisulpride Add-on Therapy in Schizophrenia Patients without Treatment Response to Second-generation Antipsychotics

Objective

The response to antipsychotics in patients with schizophrenia is still unsatisfactory. Therefore, augmentation with other antipsychotics is common in clinical situations. The purpose of this study was to evaluate the improvement of psychiatric symptoms and side effects after amisulpride add-on therapy.

Methods

Forty patients with schizophrenia or schizoaffective disorder without treatment response to second-generation antipsychotics were included in this study. Psychotic symptoms were evaluated using the Positive and Negative Syndrome Scale (PANSS) and the Korean version of Calgary Depression Scale for Schizophrenia (CDSS) at baseline, 4 weeks, and 8 weeks after the addition of amisulpride.

Results

Among the 29 subjects who completed the 8-week study, 34.5% were responders according to PANSS total score. At week 8, the mean positive (p < 0.001), negative (p < 0.001), general (p < 0.001), and total (p < 0.001) PANSS scores and CDSS scores (p = 0.002) showed significant improvement compared to baseline. There was no increase in extrapyramidal side effects according to Simpson Angus Scale (p = 0.379) and Barnes Akathisia Rating Scale (p = 0.070) and no weight gain (p = 0.308) after the add-on treatment.

Conclusion

The addition of amisulpride for schizophrenia patients without therapeutic response to second-generation antipsychotics is considered an effective and safe treatment. This study's results suggested that augmentation of second-generation antipsychotics with amisulpride could be a useful option for patients with schizophrenia unresponsive to second-generation antipsychotics. Further studies investigating the efficacy of amisulpride add-on therapy using placebo control are necessary to confirm these results.

Thalamo-Habenular Connection Differences Between Patients With Major Depressive Disorder and Normal Controls

Background: The thalamus and habenula are thought to be key brain regions in the etiology of major depressive disorder (MDD); however, few studies have investigated the structural connection between them. We compared the number of white matter tracts between the thalamus and habenula between patient with MDD and normal controls (NCs). Methods: The habenula and thalamus region of interest masks were extracted from brain magnetic resonance imaging data and individual tractography analysis was performed. First, we compared the number of fiber connections from the habenula to the thalamus between the MDD (n = 34) and NC (n = 37) groups and also compared hemispherical differences to investigate possible asymmetries. Results: There was a significant difference in the number of tracts in the right habenula-left mediodorsal thalamus pair between the two groups. For hemispherical fiber connections, the waytotal ratio of the right ipsilateral tract between the thalamus and habenula was significantly higher than that of the left ipsilateral tract in both groups. Conclusion: The number of right habenula-left mediodorsal thalamus tracts was higher in patients with MDD than in NCs. These results indicate that MDD is related to the disintegration of the left thalamus-right habenula tract function with an increased number of tracts as a compensational mechanism.

Spectral Power Analysis of Sleep Electroencephalography in Subjects with Different Severities of Obstructive Sleep Apnea and Healthy Controls

PURPOSE

Previous spectral analysis studies on obstructive sleep apnea (OSA) involved small samples, and the results were inconsistent. We performed a spectral analysis of sleep EEG based on different severities of OSA using the Sleep Heart Health Study data. This study aimed to determine the difference in EEG spectral power during sleep in the non-OSA group and with different severities of OSA in the general population.

PATIENTS AND METHODS

The participants (n = 5,804) underwent polysomnography, and they were classified into non-OSA, mild OSA, moderate OSA, and severe OSA groups. The fast Fourier transformation was used to compute the EEG power spectrum for total sleep duration within contiguous 30-second epochs of sleep. The EEG spectral powers of the groups were compared using 4,493 participants after adjusting potential confounding factors that could affect sleep EEG.

RESULTS

The power spectra differed significantly among the groups for all frequency bands (p corr < 0.001). We found that the quantitative EEG spectral powers in the beta and sigma bands of total sleep differed (p corr < 0.001) among the participants in the non-OSA group and with different severities of OSA, controlling for covariates. The beta power was higher and the sigma power was lower in the OSA groups than in the non-OSA group. The beta power decreased in the order of severe OSA, moderate OSA, mild OSA, and non-OSA.

CONCLUSION

This study suggests that there are differences between the microstructures of PSG-derived sleep EEG of non-OSA participants and those with different severities of OSA.

The rs6265 Polymorphism of the BDNF Gene Is Related to Higher-Lethality Suicide Attempts in the Korean Population

OBJECTIVE

Since the risk of suicide cannot be predicted by clinical symptoms alone, and suicide is known to have a genetic component, the discovery of genetic markers that can predict the lethality of suicide attempts is a clinically important topic. There have been many studies aiming to determine whether the rs6265 polymorphism of the BDNF gene is associated with suicidality; however, the results have been mixed, and there have been few studies investigating the relationship between this polymorphism and suicide attempt lethality.

METHODS

We assessed suicide lethality in 258 individuals who had attempted suicide using the relative risk ratio (RRR) scale and by genotyping the rs6265 polymorphism of the BDNF gene.

RESULTS

The RRR score for suicide attempts was higher in subjects with Met/Val and Val/Val genotypes than in that with a Met/Met genotype (p=0.015). The RRR score for suicide attempts was also higher in Val allele carriers (Met/Val+Val/Val) than in Met/Met homozygotes (p=0.006).

CONCLUSION

This study demonstrates the possibility that the rs6265 polymorphism of the BDNF gene could be used as a genetic marker to predict the lethality of suicide attempts, but more replication studies are needed for the application of this result in clinical practice.

Neuroimaging Biomarkers for Predicting Treatment Response and Recurrence of Major Depressive Disorder

The acute treatment duration for major depressive disorder (MDD) is 8 weeks or more. Treatment of patients with MDD without predictors of treatment response and future recurrence presents challenges and clinical problems to patients and physicians. Recently, many neuroimaging studies have been published on biomarkers for treatment response and recurrence of MDD using various methods such as brain volumetric magnetic resonance imaging (MRI), functional MRI (resting-state and affective tasks), diffusion tensor imaging, magnetic resonance spectroscopy, near-infrared spectroscopy, and molecular imaging (i.e., positron emission tomography and single photon emission computed tomography). The results have been inconsistent, and we hypothesize that this could be due to small sample size; different study design, including eligibility criteria; and differences in the imaging and analysis techniques. In the future, we suggest a more sophisticated research design, larger sample size, and a more comprehensive integration including genetics to establish biomarkers for the prediction of treatment response and recurrence of MDD.

Differences in brain surface area and cortical volume between suicide attempters and non-attempters with major depressive disorder

The neurobiological causes underlying suicidal behaviors in major depressive disorder (MDD) have not been identified. This study was performed to investigate the differences in brain cortical thickness, surface area, and volume between suicide attempters and non-attempters with MDD. We performed magnetic resonance imaging (MRI) in 38 MDD patients (18-65 years old; 18 male, 20 female) with and without a history of suicide attempts. FreeSurfer software was used to compare the cortical thickness, surface area, and volume of 19 suicide attempters with MDD and 19 suicide non-attempters with MDD, while controlling for age, sex, mean area (or volume), and severity of depression. Compared with suicide non-attempters, suicide attempters with MDD exhibited a larger surface area in the left postcentral area and left lateral occipital area and a larger cortical volume in the left postcentral area and left lateral orbitofrontal area. Suicide attempters exhibited a smaller surface area in the left superior frontal area than suicide non-attempters. The present findings provide evidence for neuroanatomical risk factors of suicide in MDD. Further research to replicate these results and determine the mechanisms underlying these findings is needed.

Risk Factors for Serious Suicide Attempts: Difference Between Older and Younger Attempters in the Emergency Department

Objective: Suicide attempts of the older adults are known to be more serious than that of the younger adults. Despite its major social impact in South Korea, the behavioral mechanism of serious suicide attempt (SSA) in old people remains to be elucidated. Thus, we investigated the risk factors for SSA in older and younger suicide attempters in the emergency department. Methods: Demographic data, clinical information, and the level of seriousness of suicide with Risk Rescue Rating Scale were compared between older (age ≥65) and younger (age <65) adults who visited the emergency department for a suicide attempt. Regression analyses were performed to identify the risk factors for SSA in these two groups. Results: Among 370 patients, 37 were older adults (10%; aged 74.41 ± 6.78), more likely to have another medical disease (p < 0.001), and a higher suicide completion rate (16.2 vs. 5.4%, p = 0.023). In the younger group, old age (B = 0.090, p < 0.001), male sex (B = -0.038, p = 0.019), and impression of schizophrenia (B = 0.074, p = 0.027) were associated with a higher risk-rescue ratio and interpersonal stress condition was associated with a lower risk-rescue ratio (B = -0.045, p = 0.006). In the older group, however, no variables were included significant in the regression model for the Risk Rescue Rating Scale. Conclusions: Demographic and clinical factors such as old age, male sex, interpersonal stress, and impression of schizophrenia were associated with lethality in the younger suicide attempters. However, no factors were associated with SSA in the older adult group. Different mechanisms may underly the lethality in old age suicide.

Decreased regional brain activity in response to sleep-related sounds after cognitive behavioral therapy for psychophysiological insomnia

AIM

Patients with psychophysiological insomnia (PI) experience hyperarousal, especially as a reaction to sound stimuli. In the current study, we explored brain activity changes in response to sleep-related sounds (SS) in patients with insomnia after cognitive behavioral therapy for insomnia (CBT-I).

METHODS

In 14 drug-free PI patients, regional brain activity in response to SS, and to white noise sound (NS) as neutral stimuli, was investigated before and after individual CBT-I using functional magnetic resonance imaging. Blood oxygen level-dependent (BOLD) signals to SS and NS were compared before and after CBT-I. In addition, the association between clinical improvement after CBT-I and changes in brain activity in response to SS and NS was analyzed.

RESULTS

Compared with baseline, regional brain activity in response to SS after CBT-I decreased in the left middle temporal and left middle occipital gyrus. In regression analysis, a reduction in the Dysfunctional Beliefs and Attitudes about Sleep (DBAS) Scale score after CBT-I was associated with decrease in brain activity in response to SS in both thalami. However, brain activity in response to NS showed no BOLD signal changes and no association with DBAS change.

CONCLUSION

Cortical hyperactivity, which may cause hyperarousal in PI, was found to decrease after CBT-I. CBT-I targeting changes in beliefs and attitudes about sleep may induce its therapeutic effects by reducing thalamic brain activity in response to sleep-related stimuli.

Low white-matter integrity between the left thalamus and inferior frontal gyrus in patients with insomnia disorder

BACKGROUND

Previous studies have reported functional and structural abnormalities in the thalamus and the pars triangularis of the inferior frontal gyrus in patients with insomnia disorder. However, no studies have been conducted on the white-matter tracts between these 2 brain regions. We aimed to compare the white-matter integrity and structure of the left thalamus–pars triangularis tracts between patients with insomnia and controls, and to characterize the relationship between white-matter integrity and clinical features in patients with insomnia.

METHODS

In total, 22 participants with insomnia disorder and 27 controls underwent overnight polysomnography and brain magnetic resonance imaging, and then completed self-report clinical questionnaires and neurocognitive tests for spatial planning. Structural and diffusion measures such as fractional anisotropy, axial diffusivity, radial diffusivity and trace were analyzed in group comparison and correlation analyses.

RESULTS

The insomnia group showed significantly lower fractional anisotropy (F = 8.647, p = 0.02) and axial diffusivity (F = 5.895, p = 0.038) in the left thalamus–pars triangularis tracts than controls. In patients with insomnia, fractional anisotropy in the tracts was correlated with the results of the Stockings of Cambridge test (r = 0.451, p = 0.034), and radial diffusivity was correlated with Epworth Sleepiness Scale score (r = 0.437, p = 0.042).

LIMITATIONS

Limitations included analyses of limited brain regions and the cross-sectional design.

CONCLUSION

The insomnia group showed decreased integrity in the left thalamus–pars triangularis tracts, and integrity was correlated with cognition and daytime sleepiness. These results may imply that insomnia is characterized by disintegration of the white-matter tract between the left thalamus and inferior frontal gyrus.

Decreased serum magnesium levels in depression: a systematic review and meta-analysis

BACKGROUND

Magnesium (Mg²⁺), an endogenous N-methyl-D-aspartate receptor antagonist, has received increased attention recently because of its role in the pathophysiology of and treatment response in depression. However, whether Mg²⁺ level is decreased in depression is not firmly established. We aimed to conduct a systematic review and meta-analysis to help making consensus for the association between Mg²⁺ levels and depression.

METHODS

A systematic search was conducted in the electronic database resources PubMed and Embase. After a careful selection of relevant studies, a meta-analysis using the random effects model was conducted in each measuring source, such as serum, plasma, and cerebrospinal fluid (CSF).

RESULTS

A total of 18 studies were included in this study. Among 11 studies that measured Mg²⁺ in the serum, Mg²⁺ level was lower in patients with depression than in controls (weighted mean difference  = -.088, 95% confidence interval  = -.164 to -.012). In the sensitivity analysis by removing studies one by one, 2 out of the 11 studies obliterated such significant differences. There were no significant differences in the Mg²⁺ levels in the studies for plasma and CSF.

CONCLUSIONS

Despite some evidence supporting an association between decreased Mg²⁺ levels and depression from studies with serum, the results of our meta-analysis urge to use caution when associating Mg²⁺ levels and depression. Future studies are needed to establish a consensus for the role of low Mg²⁺ levels in depression.

Sleep EEG spectral power is correlated with subjective-objective discrepancy of sleep onset latency in major depressive disorder

We aimed to identify the sleep electroencephalography (EEG) spectral power correlates of the subjective-objective discrepancy (SOD) of sleep onset latency (SOL) in major depressive disorder (MDD), primary insomnia (PI), and normal sleeping control (NSC) groups. We examined relative power values in standard frequency bands of the EEG spectra during the first Non-Rapid Eye Movement (NREM) sleep period as correlates of SOD of SOL between sleep diary and polysomnography in MDD (n = 36), PI (n = 19), and NSC (n = 23) groups. We also compared the relative spectral power of sleep EEG among MDD (n = 40), PI (n = 19), and NSC (n = 23) groups. SOD of SOL in MDD patients was positively correlated with relative sigma (r = 0.622, p corrected < 0.001), beta power (r = 0.559, p corrected = 0.002), and alpha power (r = 0.469, p corrected = 0.024) in the first NREM sleep period. There was no significant difference of sleep EEG power spectra among the three groups. SOD was positively correlated with high frequency EEG in MDD. High frequency EEG power is thought to be associated with hyperarousal and memory consolidation, and future larger-scale studies may further elucidate the neurophysiological mechanisms underlying SOD of sleep onset duration.

Higher Prevalence of Hypertension among Individuals with Restless Legs Syndrome: A Meta-Analysis

OBJECTIVE

This study investigated the proposed association between restless legs syndrome (RLS) and the prevalence of hypertension.

METHODS

A meta-analysis was conducted based on searches of the PUBMED, EMBASE, Cochrane Library, and Korean electronic databases. Cohort and cross-sectional studies reporting the incidence of hypertension in individuals with RLS were included. Dichotomous data were pooled to obtain an odds ratio (OR) and 95% confidence interval (CI) for the prevalence of hypertension in individuals with RLS. The main outcome measure of the study was prevalence of hypertension in patients with RLS compared with a control group.

RESULTS

One cohort study and eight cross-sectional studies were included in the meta-analysis. Individuals with RLS had an increased prevalence of hypertension (all studies: OR=1.13, 95% CI=1.04-1.23; cross-sectional studies: OR=1.12, 95% CI=1.01-1.24). However, in subgroup analyses controlling for cardiovascular risk factors, such as diabetes mellitus and dyslipidemia, the differences in the prevalence of hypertension between RLS and control patients were no longer significant.

CONCLUSION

Patients with RLS may have a higher prevalence of hypertension, according to a pooled analysis, but the results remain to be confirmed in well-designed prospective studies.

Impact of Exposure to Dim Light at Night on Sleep in Female and Comparison with Male Subjects

OBJECTIVE

Light pollution has become a social and health issue. We performed an experimental study to investigate impact of dim light at night (dLAN) on sleep in female subjects, with measurement of salivary melatonin.

METHODS

The 25 female subjects (Group A: 12; Group B: 13 subjects) underwent a nocturnal polysomnography (NPSG) session with no light (Night 1) followed by an NPSG session randomly assigned to two conditions (Group A: 5; Group B: 10 lux) during a whole night of sleep (Night 2). Salivary melatonin was measured before and after sleep on each night. For further investigation, the female and male subjects of our previous study were collected (48 subjects), and differences according to gender were compared.

RESULTS

dLAN during sleep was significantly associated with decreased total sleep time (TST; F=4.818, p=0.039), sleep efficiency (SE; F=5.072, p=0.034), and Stage R latency (F=4.664, p=0.041) for female subjects, and decreased TST (F=14.971, p<0.001) and SE (F=7.687, p=0.008), and increased wake time after sleep onset (F=6.322, p=0.015) and Stage R (F=5.031, p=0.03), with a night-group interaction (F=4.579, p=0.038) for total sample. However, no significant melatonin changes. There was no significant gender difference of the impact of dLAN on sleep, showing the negative changes in the amount and quality of sleep and the increase in REM sleep in the both gender group under 10 lux condition.

CONCLUSION

We found a negative impact of exposure to dLAN on sleep in female as well as in merged subjects. REM sleep showed a pronounced increase under 10 lux than under 5 lux in merged subjects, suggesting the possibility of subtle influences of dLAN on REM sleep.

Korean Guidelines for the Pharmacological Treatment of Social Anxiety Disorder: Initial Treatment Strategies

OBJECTIVE

The aim of the present study was to provide clinical consensus and evidence regarding initial treatment strategies for the pharmacological treatment of social anxiety disorder (SAD) in Korea.

METHODS

We prepared a questionnaire to derive a consensus from clinicians regarding their preference for the pharmacological treatment of SAD in Korea. Data regarding medication regimens and psychotropic drugs used during initial treatment, the doses used, and the pharmacological treatment duration were obtained. Responses were obtained from 66 SAD experts, and their opinions were classified into three categories (first-line, second-line, third-line) using a chi-square analysis.

RESULTS

Clinicians agreed upon first-line regimens for SAD involving monotherapy with selective serotonin reuptake inhibitors (SSRIs) or the serotonin-norepinephrine reuptake inhibitor (SNRI) venlafaxine, or combined therapy using antidepressants with betablockers or benzodiazepines on a standing or as-needed basis. First-line psychotropic drug choices for initial treatment included the following: escitalopram, paroxetine, sertraline, venlafaxine, and propranolol. The medication dosage used by domestic clinicians was found to be comparable with foreign guidelines. Domestic clinicians tended to make treatment decisions in a shorter amount of time and preferred a similar duration of maintenance treatment for SAD when compared with foreign clinicians.

CONCLUSION

This study may provide significant information for developing SAD pharmacotherapy guidelines in Korea, especially in the early stage of treatment.

Haplotype Association of the MAP2K5 Gene with Antipsychotics-Induced Symptoms of Restless Legs Syndrome among Patients with Schizophrenia

OBJECTIVE

Restless legs syndrome (RLS) is considered a genetic disease and, following a genome-wide association study conducted in 2007, the mitogen-activated protein kinase 5 (MAP2K5) gene has been regarded as the promising candidate gene for RLS. The present study investigated whether polymorphisms of MAP2K5 are associated with antipsychotics-induced RLS in schizophrenia.

METHODS

We assessed antipsychotics-induced RLS symptoms in 190 Korean schizophrenic patients using the diagnostic criteria of the International Restless Legs Syndrome Study Group. Five single-nucleotide polymorphisms (SNPs) of MAP2K5 were genotyped. We investigated genetic and haplotypic associations of these five SNPs with the risk of antipsychotics-induced RLS symptoms.

RESULTS

We divided the 190 subjects into 2 groups: 1) those with RLS symptoms (n=96) and 2) those without RLS symptoms (n=94). There were no significant intergroup differences in the distributions of the genotypes and alleles of the rs1026732, rs11635424, rs12593813, rs4489954, and rs3784709 SNPs. However, the haplotype analysis showed that the G-G-G-G-T (rs1026732-rs11635424-rs12593813-rs4489954-rs3784709) haplotype was associated with RLS symptoms (permutation p=0.033).

CONCLUSION

These data suggest that a haplotype of MAP2K5 polymorphisms confers increased susceptibility to antipsychotics-induced RLS symptoms in schizophrenic patients.

RORA Polymorphism Interacts with Childhood Maltreatment in Determining Anxiety Sensitivity by Sex: A Preliminary Study in Healthy Young Adults

Objective

Recent studies have reported associations of retinoid-related orphan receptor alpha (RORA) gene single nucleotide polymorphisms (SNPs) with depression and anxiety disorders. Based on these, we attempt to test whether RORA polymorphism is associated with anxiety sensitivity (AS), the intermediate phenotype of depression and anxiety disorders. Considering gene-environment interactions and sex differences in AS, childhood maltreatment (CM) and sex were considered as confounders.

Methods

Two-hundred and five healthy young Korean adults (female: 98, male: 107; age, 23.0±3.2 years) completed genotyping for the RORA SNP rs11071547, as well as measures for AS and CM. Generalized linear models were used to examine the main and interaction effects of RORA genotype, CM, and sex in determining AS.

Results

The main effect of RORA polymorphisms was not found (p=0.760) whereas the main effect of CM and interaction effects among sex, genotype, and maltreatment were significant on AS. In separate analyses by sex, the interaction effect between RORA genotype and maltreatment was significant only in males (p＜0.001). In females, the main effects of genotype and CM were significant (both were p＜0.001), in which both a history of CM and C genotype tended to be associated with higher AS.

Conclusion

The association between RORA polymorphism and AS might differ by sex. The interaction between RORA polymorphism and CM was significant only in males whereas RORA genotype and CM independently associated with AS in females. Further studies are encouraged to confirm the relationship between RORA polymorphism and AS.

Acute toxicity of organic antifouling biocides to phytoplankton Nitzschia pungens and zooplankton Artemia larvae

The toxicity of the antifouling biocides Irgarol 1051, Diuron, Chlorothalonil, Dichlofluanid, Sea-nine 211, Copper pyrithione, Zinc pyrithione, Ziram and Zineb were evaluated on Nitzschia pungens and Artemia larvae. Results showed that EC₅₀ for Irgarol 1051 was 0.586μgl^-1 was the strongest effect on N. pungens following by Copper pyrithione (4.908μgl^-1), Ziram (5.421μgl^-1), Zinc pyrithione (5.513μgl^-1), Diuron (6.640μgl^-1), Zineb (232.249μgl^-1), Sea-nine 211(267.368μgl^-1), Chlorothalonil (360.963μgl^-1) and Dichlofluanid (377.010μgl^-1) in 96h. In Artemia larvae, the biocides were evaluated the LC₅₀ for larval survivals at 48h. Sea-nine 211 and Copper pyrithione were 0.318 and 0.319mgl^-1. Chlorothalonil, Zinc pyrithione and Ziram were 2.683, 3.147 and 4.778mgl^-1. Irgarol 1051, Diuron, Zineb and Dichlofluanid were 9.734, 30.573, 41.170 and 154.944mgl^-1. These results provide baseline data concerning the toxicity of antifouling biocides against marine environment.

A Genome-Wide Association Study Identifies UTRN Gene Polymorphism for Restless Legs Syndrome in a Korean Population

OBJECTIVE

Restless legs syndrome (RLS) is a highly heritable and common neurological sensorimotor disease disturbing sleep. The objective of study was to investigate significant gene for RLS by performing GWA and replication study in a Korean population.

METHODS

We performed a GWA study for RLS symptom group (n=325) and non-RLS group (n=2,603) from the Korea Genome Epidemiology Study. We subsequently performed a replication study in RLS and normal controls (227 RLS and 229 controls) to confirm the present GWA study findings as well as previous GWA study results.

RESULTS

In the initial GWA study of RLS, we observed an association of rs11645604 (OR=1.531, p=1.18×10^-6) in MPHOSPH6 on chromosome 16q23.3, rs1918752 (OR=0.6582, p=1.93×10^-6) and rs9390170 (OR=0.6778, p=7.67×10^-6) in UTRN on chromosome 6q24. From the replication samples, we found rs9390170 in UTRN (p=0.036) and rs3923809 and rs9296249 in BTBD9 (p=0.045, p=0.046, respectively) were significantly associated with RLS. Moreover, we found the haplotype polymorphisms of rs9357271, rs3923809, and rs9296249 (overall p=5.69×10^-18) in BTBD9 was associated with RLS.

CONCLUSION

From our sequential GWA and replication study, we could hypothesize rs9390170 polymorphism in UTRN is a novel genetic marker for susceptibility to RLS. Regarding with utrophin, which is encoded by UTRN, is preferentially expressed in the neuromuscular synapse and myotendinous junctions, we speculate that utrophin is involved in RLS, particularly related to the neuromuscular aspects.

Resting-state functional connectivity of the amygdala in suicide attempters with major depressive disorder

In this study, we investigated the difference in resting-state functional connectivity (RSFC) of the amygdala between suicide attempters and non-suicide attempters with major depressive disorder (MDD) using functional magnetic resonance imaging (fMRI). This study included 19 suicide attempters with MDD and 19 non-suicide attempters with MDD. RSFC was compared between the two groups and the regression analyses were conducted to identify the correlation between RSFC and Scale for Suicide Ideation (SSI) scores in the suicide attempt group. Statistical significance was set at p-value (uncorrected) <0.005 with k≥28 voxels. Compared with non-suicide attempters, suicide attempters showed significantly increased RSFC of the left amygdala with the right insula and left superior orbitofrontal area, and increased RSFC of the right amygdala with the left middle temporal area. The regression analysis showed a significant correlation between the SSI total score and RSFC of the right amygdala with the right parahippocampal area in the suicide attempt group. The present RSFC findings provide evidence of a functional neural basis and will help reveal the pathophysiology underlying suicidality in subjects with MDD.

Dementia Care by Healthy Elderly Caregivers Is Associated with Improvement of Patients' Memory and the Caregivers' Quality of Life: A Before and After Study

OBJECTIVE

The provision of care for elderly people with dementia by healthy elderly caregivers is one of the new health-care paradigms in South Korea. The aim of this study was to determine whether this type of care, which includes cognitive stimulation, would improve the cognitive function of dementia patients and the quality of life of the healthy elderly caregiver.

METHODS

Totals of 132 dementia patients and 197 healthy elderly caregivers participated in this study. We evaluated the cognitive function of the dementia patients at baseline and after providing the program for 6 months using the Korean version of the Consortium to Establish a Registry for Alzheimer's disease, 1st Edition (CERAD-K). We also evaluated the quality of life of the healthy elderly caregivers using the World Health Organization Quality of Life-Short Version (WHOQOL-BREF) at baseline and after 6 months.

RESULTS

The word-list memory results of CERAD-K for the included dementia patients improved after 6 months (Z=-2.855, p=0.004). The WHOQOL-BREF score among the elderly caregiver also improved significantly (Z=-2.354, p=0.019).

CONCLUSION

These data suggest that dementia care is associated with improvements in both the cognitive function of dementia patients and the quality of life of the healthy elderly caregivers.

Formula for predicting OSA and the Apnea-Hypopnea Index in Koreans with suspected OSA using clinical, anthropometric, and cephalometric variables

PURPOSE

This study developed formulas to predict obstructive sleep apnea (OSA) and the Apnea-Hypopnea Index (AHI) in Korean patients with suspected OSA using clinical, anthropometric, and cephalometric variables.

METHODS

We evaluated relevant variables in 285 subjects with suspected OSA. These included demographic characteristics, sleep-related symptoms, medical history, clinical scales, anthropometric measurements including facial surface measurements, and cephalometric measurements. All participants underwent full-night laboratory polysomnography. The prediction formula for the probability of OSA was created by logistic regression analysis and confirmed by the bootstrap resampling technique. The formula for predicting the AHI was developed using multiple linear regression analysis.

RESULTS

The probability of having OSA was as follows: p = 1 / (1 + exponential (exp)^-f ), where f = -16.508 + 1.445 × loudness of snoring 4 + 0.485 × loudness of snoring 3 + 0.078 × waist circumference + 0.209 × subnasale-to-stomion distance + 0.183 × thickness of the uvula (UTH) supine + 0.041 × age. The AHI prediction formula was as follows: -112.606 + 3.516 × body mass index + 0.683 × mandibular plane-hyoid supine + 10.915 × loudness of snoring 4 + 6.933 × loudness of snoring 3 + 1.297 × UTH supine + 0.272 × age.

CONCLUSION

This is the first study to establish formulas to predict OSA and the AHI in Koreans with suspected OSA using cephalometric and other variables. These results will contribute to prioritizing the order in which patients with suspected OSA are referred for polysomnography.

Cognitive Behavioral Therapy Using a Mobile Application Synchronizable With Wearable Devices for Insomnia Treatment: A Pilot Study

STUDY OBJECTIVES

The use of telemedicine with a mobile application (MA) and a wearable device (WD) for the management of sleep disorders has recently received considerable attention. We designed an MA synchronizable with a WD for insomnia treatment. Our pilot study determined the efficacy of simplified group cognitive behavioral therapy for insomnia (CBT-I) delivered using our MA and assessed participant adherence to and satisfaction with the device.

METHODS

The efficacy of the CBT-I using MA (CBT-I-MA) was assessed by comparing sleep variables (sleep efficiency [SE], Insomnia Severity Index [ISI], and Pittsburgh Sleep Quality Inventory [PSQI] scores) before and after a 4-week treatment protocol in 19 patients with insomnia disorder patients. SE was assessed using a sleep diary, actigraphy, and the PSQI.

RESULTS

The intervention significantly improved all three measures of SE (P < .05), and the response rate to treatment was high (94.7%). Total ISI and PSQI scores and sleep latency, as measured by the sleep diary, improved significantly. Participants showed relatively good adherence to our MA, and sleep diary entries were made on 24.3 ± 3.8 of 28 days. Moreover, 94.7% of the participants reported that our MA was effective for treating insomnia.

CONCLUSIONS

Our pilot study suggested the clinical usefulness of a CBT-I-MA. We expect that our findings will lead to further development and replication studies of CBT-I-MA.

rs7968606 polymorphism of ANKS1B is associated with improvement in the PANSS general score of schizophrenia caused by amisulpride

A recent genome-wide pharmacogenomics study showed that the rs7968606 single-nucleotide polymorphism (SNP) of the ankyrin repeat and sterile alpha motif domain-containing protein 1B (ANKS1B) gene approached the threshold of statistical significance. The aim of this study was to determine the association between the rs7968606 SNP of ANKS1B and the treatment response to amisulpride in schizophrenia patients. In total, 154 participants were enrolled from six university hospitals in Korea. All the subjects were interviewed before and after 6 weeks of amisulpride treatment with the aid of the positive and negative syndrome scale and the clinical global impression-severity scale. Genotyping for the rs7968606 SNP of ANKS1B was performed in 101 subjects. Both the decrease (t = -2.067, p = 0.041) and improvement rate (t = -1.990, p = 0.049) in the positive and negative syndrome scale general score differed significantly between T-allele carriers and noncarriers of this polymorphism after 6 weeks of amisulpride treatment. To the best of our knowledge, this is the first genetic association study of the relationship between the rs7968606 SNP of ANKS1B and the response of schizophrenia patients to treatment with amisulpride. Future larger-scale studies involving more SNPs of ANKS1B will improve the understanding of the pharmacogenetics underlying the treatment responses to amisulpride.

Decrease in fMRI brain activation during working memory performed after sleeping under 10 lux light

The aim of this study was to investigate the effect of exposure to dim light at night (dLAN) when sleeping on functional brain activation during a working-memory tasks. We conducted the brain functional magnetic resonance imaging (fMRI) analysis on 20 healthy male subjects. All participants slept in a polysomnography laboratory without light exposure on the first and second nights and under a dim-light condition of either 5 or 10 lux on the third night. The fMRI scanning was conducted during n-back tasks after second and third nights. Statistical parametric maps revealed less activation in the right inferior frontal gyrus (IFG) after exposure to 10-lux light. The brain activity in the right and left IFG areas decreased more during the 2-back task than during the 1- or 0-back task in the 10-lux group. The exposure to 5-lux light had no significant effect on brain activities. The exposure to dLAN might influence the brain function which is related to the cognition.

Association of CLOCK, ARNTL, PER2, and GNB3 polymorphisms with diurnal preference in a Korean population

Polymorphisms in human circadian genes are potential genetic markers that affect diurnal preference in several populations. In this study, we evaluated whether four polymorphisms in circadian genes CLOCK, ARNTL, PER2, and GNB3 were associated with diurnal preference in a Korean population. In all, 499 healthy subjects were genotyped for four functional polymorphisms in CLOCK, ARNTL, PER2, and GNB3. Composite scale of morningness (CSM) was applied to measure phenotype patterns of human diurnal preference. In addition, three subscale scores, i.e. "morningness," "activity planning," and "morning alertness," were extracted from the CSM. No significant associations were observed between CSM scores and CLOCK (rs1801260) genotype or T allele carrier status, CSM scores and ARNTL (rs2278749) C allele carrier status, and CSM scores and GNB3 (rs5443) genotype or C allele carrier status. However, total CSM scores and scores of its subscales were significantly associated with PER2 (rs934945) genotype (p = 0.010, p = 0.018, and p = 0.005 for total, morningness, and activity planning, respectively) and G allele carrier status (p = 0.003, p = 0.005, and p = 0.002 for total, morningness, and activity planning, respectively). The best model result obtained by performing multifactor dimensionality reduction analysis ([Formula: see text]² = 11.2798, p = 0.0008) indicated that interaction among C/T single nucleotide polymorphism (SNP) in ARNTL, C/T SNP in GNB3, and G/A SNP in PER2 synergistically affected the risk associated with diurnal preference toward eveningness. These results suggest that circadian gene PER2 is associated with diurnal preference in healthy Korean population. Although polymorphisms in ARNTL and GNB3 were not significantly associated with diurnal preference, their interactions with the polymorphism in PER2 may synergistically increase the risk of diurnal preference toward eveningness.

Molecular circadian rhythm shift due to bright light exposure before bedtime is related to subthreshold bipolarity

This study examined the link between circadian rhythm changes due to bright light exposure and subthreshold bipolarity. Molecular circadian rhythms, polysomnography, and actigraphy data were studied in 25 young, healthy male subjects, divided into high and low mood disorder questionnaire (MDQ) score groups. During the first 2 days of the study, the subjects were exposed to daily-living light (150 lux) for 4 hours before bedtime. Saliva and buccal cells were collected 5 times a day for 2 consecutive days. During the subsequent 5 days, the subjects were exposed to bright light (1,000 lux), and saliva and buccal cell samples were collected in the same way. Molecular circadian rhythms were analyzed using sine regression. Circadian rhythms of cortisol (F = 16.956, p < 0.001) and relative PER1/ARNTL gene expression (F = 122.1, p < 0.001) showed a delayed acrophase in both groups after bright light exposure. The high MDQ score group showed a significant delay in acrophase compared to the low MDQ score group only in salivary cortisol (F = 8.528, p = 0.008). The high MDQ score group showed hypersensitivity in cortisol rhythm shift after bright light exposure, suggesting characteristic molecular circadian rhythm changes in the high MDQ score group may be related to biological processes downstream from core circadian clock gene expression.

Advanced Circadian Phase in Mania and Delayed Circadian Phase in Mixed Mania and Depression Returned to Normal after Treatment of Bipolar Disorder

Disturbances in circadian rhythms have been suggested as a possible cause of bipolar disorder (BD). Included in this study were 31 mood episodes of 26 BD patients, and 18 controls. Circadian rhythms of BD were evaluated at admission, at 2-week intervals during hospitalization, and at discharge. All participants wore wrist actigraphs during the studies. Saliva and buccal cells were obtained at 8:00, 11:00, 15:00, 19:00, and 23:00 for two consecutive days. Collected saliva and buccal cells were used for analysis of the cortisol and gene circadian rhythm, respectively. Circadian rhythms had different phases during acute mood episodes of BD compared to recovered states. In 23 acute manic episodes, circadian phases were ~ 7 hour advanced (equivalent to ~ 17 hour delayed). Phases of 21 out of these 23 cases returned to normal by ~ 7 hour delay along with treatment, but two out of 23 cases returned to normal by ~ 17 hour advance. In three cases of mixed manic episodes, the phases were ~ 6–7 hour delayed. For five cases of depressive episodes, circadian rhythms phases were ~ 4–5 hour delayed. After treatment, circadian phases resembled those of healthy controls. Circadian misalignment due to circadian rhythm phase shifts might be a pathophysiological mechanism of BD.

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Bipolar disorder in acute mood episodes showed circadian dysregulation due to phase shifts which returned to normal after treatment.

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Acute manias were ~ 7 h circadian phase advanced, mixed manias were > 6 h delayed, whereas depressions were 4-5 h delayed compared to the controls.

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Circadian dysregulation due circadian rhythm phase shifts might be a pathophysiological mechanism of bipolar disorder.

Bipolar disorder is a common mental disorder characterized by mood disturbances with alternating episodes of mania and depression. Circadian rhythms are rhythms of about 24 h found in many body functions. We repeatedly measured circadian rhythms in bipolar disorder patients during hospitalization. Acute manic episodes were associated with circadian dysregulation of ~ 7 hour phase advances, mixed manias were > 6 hour delayed, whereas bipolar depression was associated with 4–5 hour phase delays compared to the controls. After treatment, the shifted rhythms recovered to the normal range. This study suggests that novel chronotherapy approaches based on our findings might be found useful for the prevention and treatment of bipolar disorder.

Prolactin and macroprolactin levels in psychiatric patients receiving atypical antipsychotics: A preliminary study

The aims of this study were to clarify whether atypical antipsychotics can elevate serum levels of both macroprolactin and prolactin, and whether the macroprolactin levels differ according to the type of atypical antipsychotic being taken. In total, 245 subjects were enrolled consecutively in 6 hospitals. Serum prolactin and macroprolactin levels were measured at a single time point during maintenance antipsychotic monotherapy. The mean total serum prolactin levels including macroprolactin were 11.91, 20.73, 16.41, 50.83, 12.84, and 59.1ng/mL for patients taking aripiprazole, blonanserin, olanzapine, paliperidone, quetiapine, and risperidone, respectively, while those for macroprolactin were 1.71, 3.86, 3.73, 7.28, 2.77, and 8.0ng/mL. The total prolactin and macroprolactin levels were significantly higher among those taking paliperidone and risperidone than among those taking any of the other antipsychotics (p<0.01). Moreover, there was a strong positive correlation between serum levels of prolactin and macroprolactin. Sexual dysfunction was reported in 35.5% (87/245) of the total subjects. However, the total prolactin level did not differ significantly between subjects with and without sexual dysfunction except gynecomastia. These findings suggest that treatment with risperidone and paliperidone can induce hyperprolactinemia and macroprolactinemia in psychiatric patients.

Decreased regional gray matter volume in suicide attempters compared to suicide non-attempters with major depressive disorders

OBJECTIVE

This study investigated regional gray matter (GM) volume differences between suicide attempters and suicide non-attempters with major depressive disorder (MDD) and their relationship with psychological risk factors for suicidality.

METHODS

MDD patients with and without a suicide attempt history (n=19 in each group) participated. The Hamilton Depression Rating Scale, Clinical Global Impression (severity subscale), Scale for Suicide Ideation (SSI), Risk-Rescue Rating (RRR), Beck Hopelessness Scale (BHS), Barrett Impulsivity Scale, Eysenck Personality Questionnaire, and Ways of Coping Checklist (WCCL) were administered. T1-weighted structural magnetic resonance imaging scans were acquired to evaluate changes in GM volume. Voxel-based morphometry was performed using the SPM 8 software package. Two-sample t-tests were used during second-level group comparison analysis; partial correlation analysis controlling for gender and age identified associations between regional GM volume and psychological measures.

RESULTS

Suicide attempters exhibited significantly decreased GM volume in the left angular gyrus (p<0.001, uncorrected) and right cerebellum (p<0.001, uncorrected). GM volume in the left angular gyrus was inversely correlated with BHS scores (r=-0.55, p<0.01) and positively correlated with the Seeking Social Support subscale of the WCCL (r=0.43, p<0.01).

CONCLUSION

These findings provide evidence of a neural basis of suicidal behaviors in MDD. In particular, reduced GM volume in the left angular gyrus may be a neurobiological marker of suicidality in depressed patients.

The associations of morningness-eveningness with anger and impulsivity in the general population

The aim of this study was to investigate the relationships among morningness-eveningness, impulsivity and anger in the general population. A total of 1000 community-dwelling subjects (500 males) aged 20-77 years (mean± SD age: 39.6 ± 11.6 years) completed the morningness-eveningness questionnaire (MEQ), Barratt impulsiveness scale (BIS), Spielberger State-Trait Anger Expression Inventory (STAXI) and Center for Epidemiologic Studies Depression Scale. Moderation and mediation analyses were performed to determine whether the relationship between two variables depended on the third variable, referred to as a moderator, and whether the third variable, known as a mediator, was associated with the other two variables establishing causation. The MEQ scores exhibited significant negative associations with BIS (p < 0.001) and STAXI (p < 0.001) scores, and high scores on the BIS were associated with high scores on the STAXI (p < 0.001). Impulsivity, as measured by the BIS, played a role as a moderator (p < 0.001) in the relationship between MEQ and STAXI, and anger, as measured by the STAXI, acted as moderator (p = 0.030) in the association between MEQ and BIS. However, after controlling for the interaction of the BIS and MEQ, the MEQ scores did not significantly predict STAXI scores (p = 0.070). Additionally, the effect size of the mediating effect of the BIS scores on the relationship between the MEQ and STAXI (percent mediation: 53.2%) was larger than that of the STAXI scores on the association between the MEQ and BIS (percent mediation: 31.8%). The present results demonstrate that morningness-eveningness was closely related with both impulsivity and anger in the general population. Furthermore, these findings suggest that impulsivity may exercise a great influence on the association between morningness-eveningness and anger in two ways: as a moderator by modulating this relationship based on the level of impulsivity and as a mediator by acting as an intermediary factor.

Geographical and temporal variations in the prevalence of mental disorders in suicide: Systematic review and meta-analysis

BACKGROUND

In contrast to the previous studies reporting that most suicides occur among people with mental disorders, recent studies have reported various rates of mental disorders in suicide in different geographical regions. We aimed to comprehensively investigate the factors influencing the variation in the prevalence of mental disorders reported among suicide victims.

METHOD

The authors searched Embase, Medline, Web of Science, and the Cochrane Library to identify psychological autopsy studies reporting the prevalence of any mental disorders among suicide victims. A meta-regression analysis was conducted to identify the potential effects of geographical regions, the year of publication, measurements of personality disorder, measurements of comorbidity, and the ratio of females on the prevalence of mental disorders in addition to examining the heterogeneity across studies.

RESULTS

From 4475 potentially relevant studies, 48 studies met eligibility criteria, with 6626 suicide victims. The studies from East Asia had a significantly lower mean prevalence (69.6% [95% CI=56.8 to 80.0]) than those in North America (88.2% [95% CI=79.7-93.5]) and South Asia (90.4% [95% CI=71.8-97.2]). The prevalence of any mental disorder decreased according to the year of publication (coefficients=-0.0715, p<0.001).

LIMITATIONS

Substantial heterogeneities were identified within all subgroup analyses.

CONCLUSIONS

The prevalence of mental disorders among suicide cases seemed relatively low in the East Asia region, and recently published studies tended to report a lower prevalence of mental disorders. The link between the risk factors and suicide in the absence of a mental disorder should be examined in different geographical and sociocultural contexts.

The relationship between poor performance on attention tasks and increased suicidal ideation in adolescents

Our goal was to examine the relationship between attention and suicidal ideation in a school-based adolescent population. This cross-sectional study involved 2,462 students from eight high schools in South Korea (1,021 males and 1,441 females, mean age 17.3 ± 0.6 years). The participants completed the Beck Scale for Suicide Ideation (SSI) and the Beck Depression Inventory (BDI) and took part in computerized attention tasks. Participants with high SSI scores (16 or higher) exhibited a higher mean number of omission errors (OEs) and commission errors (CEs) on the visual sustained attention tasks than did participants with low SSI scores (p < 0.001 and p < 0.001, respectively). On the divided attention tasks, the high SSI group exhibited a higher mean number of CEs than the low SSI group did (p < 0.001). In a general linear model adjusting for age, gender, and high BDI (10 or higher), membership in the high OE group in the visual sustained attention tasks was associated with high SSI scores (p = 0.015). Belonging to the high OE or CE group in the divided attention tasks were associated with high SSI scores (p = 0.024 and p = 0.035, respectively). For both the visual sustained and divided attention tasks, interactions between gender and high OE rates were significant (p ≤ 0.001 and p = 0.013, respectively). In the post hoc analysis, membership in the high OE group was associated with high SSI scores for girls. In a multiple linear regression analysis including all participants and controlling for age, gender, and BDI scores, higher numbers of OEs and CEs on the visual sustained attention tasks predicted higher SSI scores (p < 0.001 and p = 0.019, respectively). On the divided attention task, the number of CEs was positively correlated with the SSI score (p = 0.031). The findings of this study indicate an association between attention deficits and increased suicidal ideation in adolescents after controlling for depressed mood. The current results suggest a direct link between attention deficits and increased suicidality independent of depressive symptoms in adolescents.