Identifying unique subgroups in suicide risks among psychiatric outpatients.

BACKGROUND: The presence of psychiatric disorders is widely recognized as one of the primary risk factors for suicide. A significant proportion of individuals receiving outpatient psychiatric treatment exhibit varying degrees of suicidal behaviors, which may range from mild suicidal ideations to overt suicide attempts. This study aims to elucidate the transdiagnostic symptom dimensions and associated suicidal features among psychiatric outpatients. METHODS: The study enrolled patients who attended the psychiatry outpatient clinic at a tertiary hospital in South Korea (n = 1, 849, age range = 18-81; 61% women). A data-driven classification methodology was employed, incorporating a broad spectrum of clinical symptoms, to delineate distinctive subgroups among psychiatric outpatients exhibiting suicidality (n = 1189). A reference group of patients without suicidality (n = 660) was included for comparative purposes to ascertain cluster-specific sociodemographic, suicide-related, and psychiatric characteristics. RESULTS: Psychiatric outpatients with suicidality (n = 1189) were subdivided into three distinctive clusters: the low-suicide risk cluster (Cluster 1), the high-suicide risk externalizing cluster (Cluster 2), and the high-suicide risk internalizing cluster (Cluster 3). Relative to the reference group (n = 660), each cluster exhibited distinct attributes pertaining to suicide-related characteristics and clinical symptoms, covering domains such as anxiety, externalizing and internalizing behaviors, and feelings of hopelessness. Cluster 1, identified as the low-suicide risk group, exhibited less frequent suicidal ideation, planning, and multiple attempts. In the high-suicide risk groups, Cluster 2 displayed pronounced externalizing symptoms, whereas Cluster 3 was primarily defined by internalizing and hopelessness symptoms. Bipolar disorders were most common in Cluster 2, while depressive disorders were predominant in Cluster 3. DISCUSSION: Our findings suggest the possibility of differentiating psychiatric outpatients into distinct, clinically relevant subgroups predicated on their suicide risk. This research potentially paves the way for personalizing interventions and preventive strategies that address cluster-specific characteristics, thereby mitigating suicide-related mortality among psychiatric outpatients.

Life stress, sleep disturbance and depressive symptoms: The moderating role of prefrontal activation during emotion regulation.

OBJECTIVES: Evidence suggests that emotion regulation difficulty may play an important role in the association between life stress, sleep disturbance and depressive symptoms. We proposed two models depicting the possible moderating roles of prefrontal cortex activation during emotion regulation in the associations among these variables and tested them. We hypothesized that (1) the association between stress and sleep disturbance would differ across prefrontal cortex activation during emotion regulation (moderation model) and (2) the indirect effects of stress on depressive symptoms through sleep disturbance would depend on prefrontal cortex activation during emotion regulation (moderated mediation model). METHODS: Forty-eight healthy adults without sleep disorders based on nocturnal polysomnography participated in this study. They received functional magnetic resonance imaging scans while performing an emotion regulation task. They also completed questionnaires assessing life stress, sleep disturbance and depressive symptoms. The proposed models were tested using the PROCESS macro for SPSS. RESULTS: As hypothesized, there was a significant moderating effect of prefrontal cortex activation during emotion regulation on the association between life stress and sleep disturbance. Furthermore, right lateral prefrontal cortex activation had a moderating role in the indirect effect of life stress on depressive symptoms through sleep disturbance. CONCLUSION: These findings highlight the important role of prefrontal cortex function during emotion regulation in the associations between stress, sleep disturbance and depressive symptoms. Increasing lateral prefrontal cortex recruitment when regulating the emotional response to negative life events may be critical for the prevention and intervention of depression as well as sleep problems.

Associations between defense mechanisms and life satisfaction among North Korean refugees.

BACKGROUND: The present study investigated associations between defense mechanisms and life satisfaction among North Korean refugees living in South Korea. METHODS: A total of 178 North Korean refugees completed the Korean version of the Defense Style Questionnaire, a revised version of the Ways of Thinking of North Korean Defectors scale, the Center for Epidemiologic Studies-Depression Scale, and the State-Trait Anxiety Inventory. Multiple stepwise regression analysis was performed to investigate the defense mechanisms associated with North Korean refugees' life satisfaction in South Korea. RESULTS: Among defense mechanisms, denial most strongly predicted higher overall and economic satisfaction among North Korean refugees living in South Korea (ß = 0.145, p < 0.01; ß = 0.137, p = 0.03, respectively) after controlling for age, gender, anxiety, depression, and number of traumatic events experienced. Furthermore, resignation predicted lower overall (ß = -0.206, p < 0.001) and economic satisfaction (ß = -0.134, p = 0.02). However, the association between resignation and life satisfaction was not significant after controlling for depression, anxiety, and number of traumatic events experienced. CONCLUSIONS: Specific defense mechanisms such as high denial and low resignation were associated with life satisfaction in South Korea among North Korean refugees. Our findings suggest that refugees' psychological defense mechanisms may affect their satisfactory resettlement.

Alexithymia and frontal-amygdala functional connectivity in North Korean refugees.

BACKGROUND: Refugees commonly experience difficulties with emotional processing, such as alexithymia, due to stressful or traumatic experiences. However, the functional connectivity of the amygdala, which is central to emotional processing, has yet to be assessed in refugees. Thus, the present study investigated the resting-state functional connectivity of the amygdala and its association with emotional processing in North Korean (NK) refugees. METHODS: This study included 45 NK refugees and 40 native South Koreans (SK). All participants were administered the Toronto Alexithymia Scale (TAS), Beck Depression Inventory (BDI), and Clinician-administered PTSD Scale (CAPS), and differences between NK refugees and native SK in terms of resting-state functional connectivity of the amygdala were assessed. Additionally, the association between the strength of amygdala connectivity and the TAS score was examined. RESULTS: Resting-state connectivity values from the left amygdala to the bilateral dorsolateral prefrontal cortex (dlPFC) and dorsal anterior cingulate cortex (dACC) were higher in NK refugees than in native SK. Additionally, the strength of connectivity between the left amygdala and right dlPFC was positively associated with TAS score after controlling for the number of traumatic experiences and BDI and CAPS scores. CONCLUSIONS: The present study found that NK refugees exhibited heightened frontal-amygdala connectivity, and that this connectivity was correlated with alexithymia. The present results suggest that increased frontal-amygdala connectivity in refugees may represent frontal down-regulation of the amygdala, which in turn may produce alexithymia.

Association between snoring and heart rate variability in adolescents: effects of gender and insufficient sleep.

PURPOSE: We explored the association between subjective snoring frequency and heart rate variability (HRV) in a healthy adolescent population. METHODS: A total of 102 healthy adolescents were recruited from high schools in South Korea, and reported their sleep habits and snoring frequency. HRV was assessed to indirectly measure autonomic function. We assessed correlations between snoring frequency and HRV indices. We also investigated the effects of sex and behaviorally induced insufficient sleep syndrome (BISS) on the associations between HRV parameters and snoring frequency. RESULTS: Overall, significant correlations were apparent between snoring frequency and HRV indices including the standard deviation of the normal-to-normal intervals (SDNN) and the low-frequency/high-frequency (LF/HF) ratio. Associations were more evident in males and those with BISS compared to females and those without BISS. CONCLUSIONS: Our findings suggest that snoring changes autonomic nervous system (ANS) activity in adolescents; the changes are more dramatic in males and those with insufficient sleep.

Effects of Narrative Exposure Therapy on Posttraumatic Stress Disorder, Depression, and Insomnia in Traumatized North Korean Refugee Youth.

Refugees affected by multiple traumatic stressors are at high risk for developing trauma-related mental disorders, including posttraumatic stress disorder (PTSD), depression, and insomnia, which is sometimes overlooked. The present study examined the effectiveness of narrative exposure therapy (NET) on trauma-related symptoms in a sample of North Korean refugee youth. We focused on sleep patterns in addition to changes in symptom severity for PTSD, depression, and internalizing and externalizing symptoms. North Korean refugee youth (N = 20) with PTSD were assigned to either an NET-based treatment group or a control group, which consisted of treatment as usual (TAU). There were clinically significant reductions in PTSD, depression, and internalizing and externalizing symptoms for the NET group, Hedges' g = 3.6, but not the TAU group. The change in diagnostic status for PTSD was more notable for participants in the NET group compared to the TAU group. Of note, NET also produced a significant improvement in insomnia symptoms and sleep quality, Hedges' g = 2.1. The substantial recovery regarding overall posttraumatic symptoms in the NET group was observed 2 weeks after the end of treatment and remained stable at 6-month follow-up. The results of the present study suggest that NET may be a treatment option for traumatized North Korean refugee youth and may also be effective for the treatment of sleep problems that arise from traumatic experiences.

Psychological Development during Medical School Clerkship: Relationship to Resilience.

OBJECTIVE: The authors investigated changes in medical students' defenses during clerkship and examined the effects of these changes on students' resilience. METHODS: Between 2012 and 2014, all year-2 preclinical students (N = 249) at Gyeongsang National University Medical School were asked to participate. Those who agreed to participate (N = 237) completed the Korean version of the Defense Style Questionnaire (K-DSQ) and the Connor-Davidson resilience scale-10 (CD-RISC-10). After clerkship, students who proceeded to year 4 in 2 years (n = 187 (93 females), aged 24-38 years (mean, 28.9 ± 2.8 years)) completed the K-DSQ, CD-RISC-10, and the Korean version of the Hospital Anxiety and Depression Scale (K-HADS) in September 2014, 2015, and 2016. RESULTS: The use of adaptive (W = 11,603.5, p < 0.001, r = 0.39) and self-inhibiting (W = 10,901.5, p < 0.001, r = 0.32) styles increased significantly after clerkship. A multiple linear regression analysis showed that changes in adaptive defense styles (B = 1.336, SE = 0.386, ß = 0.218, p = 0.001) during clerkship were significantly related to resilience after adjusting for age, sex, depression, and anxiety. CONCLUSIONS: Both positive personality development and maladaptive changes in defenses were evident. An increase in the adaptive defense style score was related to resilience.

Stroop Task-Related Brain Activity in Patients With Insomnia: Changes After Cognitive-Behavioral Therapy for Insomnia.

Objective/Background: In the present study, we compared differences in brain activity during the Stroop task between patients with chronic insomnia disorder (CID) and good sleepers (GS). Furthermore, we evaluated changes in Stroop task-related brain activity after cognitive-behavioral therapy for insomnia (CBT-I). Participants/Methods: The final analysis included 21 patients with CID and 25 GS. All participants underwent functional magnetic resonance imaging (fMRI) while performing the color-word Stroop task. CBT-I, consisting of 5 sessions, was administered to 14 patients with CID in the absence of medication. After CBT-I, fMRI was repeated in the patients with CID while performing the same task. Sleep-related questionnaires and sleep variables from a sleep diary were also obtained before and after CBT-I. Results: No significant differences in behavioral performance in the Stroop task or task-related brain activation were observed between the CID and GS groups. No changes in behavioral performance or brain activity were found after CBT-I. However, clinical improvement in the Insomnia Severity Index (ISI) score was significantly associated with changes in the Stroop task-related regional blood oxygen level-dependent signals in the left supramarginal gyrus. Conclusions: Our findings suggest that cognitive impairment in patients with CID was not detectable by the Stroop task or Stroop task-related brain activation on fMRI. Moreover, there was no altered brain activity during the Stroop task after CBT-I. However, the ISI score reflected changes in the neural correlates of cognitive processes in patients with CID after CBT-I.

Association between delayed recall and T2* relaxation time of the subiculum in adolescents: Implications for ultra-high-field magnetic resonance imaging.

AIM: The aim of this study was to assess neuropsychological correlations with the T2* relaxation time (T2*-RT) of hippocampal subregions in adolescents using ultra-high-field (UHF) 7.0-T magnetic resonance imaging (MRI). METHODS: We assessed the T2*-RT of hippocampal subregions in 31 healthy 11th- or 12th-grade high school students using an UHF 7.0-T MRI system. T2*-RT of the cornu ammonis (CA) 1, CA2, CA3, and CA4 subregions and the subiculum were calculated for both the left and right hippocampus. Seven subtests of the Cambridge Neuropsychological Test Automated Battery were administered to the subjects to assess visuospatial memory. RESULTS: Poor performances in delayed recall in the pattern-recognition test were significantly correlated with longer T2*-RT in the bilateral subiculum (right, r = -0.480, P = 0.006; left, r = -0.648, P < 0.001) and the left CA2 (r = -0.480, P = 0.006). CONCLUSION: This study showed that longer T2*-RT in the subiculum were associated with poorer performances in delayed recall in the visual memory tasks. This finding suggests that the subiculum might play a predominant role in delayed recall in adolescents.

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.

Comparison of the Effects of Quetiapine XR and Lithium Monotherapy on Actigraphy-Measured Circadian Parameters in Patients With Bipolar II Depression.

PURPOSE/BACKGROUND: The aim of this study was to evaluate the effects of quetiapine XR and lithium on actigraphy-measured circadian parameters in patients with bipolar II depression. METHODS/PROCEDURES: This was an 8-week, open-label, prospective, randomized comparative study. The assessments included the 17-item Hamilton Depression Rating Scale score and actigraphic measures concerning the previous 7 days, collected at each visit (weeks 0 [baseline], 1, 2, 4, 6, and 8); the actigraphic data were analyzed with a cosinor analysis. FINDINGS/RESULTS: Medication, time, and the interaction between medication and time were significantly associated with acrophase for the entire group (Ps = 0.003, 0.020, and 0.042, respectively). More specifically, acrophase was significantly delayed at weeks 1 and 6 (Ps = 0.004 and 0.039, respectively) in the quetiapine XR group. The F statistics significantly increased over time for the entire group (P < 0.001), and there was a significant increase in F statistics on weeks 4 and 6 in the quetiapine XR group (Ps = 0.016 and 0.020, respectively) and on weeks 4 and 8 in the lithium group (Ps = 0.001 and 0.016, respectively). In addition, scores on the 17-item Hamilton Depression Rating Scale were significantly associated with the F statistics during 8 weeks for the entire group (P = 0.008). IMPLICATIONS/CONCLUSIONS: Both quetiapine XR and lithium affected several circadian parameters, including peak activity time and robustness of circadian rhythm, but exerted different effects on acrophase in patients with bipolar II depression. In particular, clinical depressive symptoms were associated with robustness of circadian rhythm during the course of the 8-week treatment.

The Effect of Traumatic Experiences and Psychiatric Symptoms on the Life Satisfaction of North Korean Refugees.

BACKGROUND: Successful adaptation of refugees to a new society can be hindered by traumatic experiences and psychiatric symptoms. This study aims to examine the relationship between trauma, psychiatric symptoms and life satisfaction of North Korean refugees resettled in South Korea. METHODS: A total of 211 North Korean refugees living in South Korea completed a series of questionnaires on the history of their previous traumatic experiences, life satisfaction in South Korea, depression, anxiety, somatization and post-traumatic stress disorder (PTSD) symptoms. RESULTS: North Korean refugees who had experienced more traumatic events were less satisfied with their economic status in South Korea. Severe depression, anxiety, somatization or PTSD symptoms negatively correlated with their overall satisfaction in South Korea. In the stepwise regression model including all psychiatric symptoms and the number of traumatic experiences as dependent variables, only anxiety, but not trauma, predicted lower life satisfaction in South Korea. CONCLUSIONS: Traumatic experiences of North Korean refugees negatively affected the life satisfaction, especially the economic satisfaction, in South Korea. Since the negative effect of trauma was mainly mediated by psychiatric symptoms, the strategy of relieving psychiatric symptoms of traumatized refugees may help the adaptation of refugees.

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 Impact of Celebrity Suicide on Subsequent Suicide Rates in the General Population of Korea from 1990 to 2010.

The association between celebrity suicide and subsequent increase in suicide rates among the general population has been suggested. Previous studies primarily focused on celebrity suicides in the 2000s. To better understand the association, this study examined the impacts of celebrity suicides on subsequent suicide rates using the data of Korean celebrity suicides between 1990 and 2010. Nine celebrity suicides were selected by an investigation of media reports of suicide deaths published in three major newspapers in Korea between 1990 and 2010. Suicide mortality data were obtained from the National Statistical Office of Korea. Seasonal autoregressive integrated moving average models with intervention analysis were used to test the impacts of celebrity suicides, controlling for seasonality. Six of the 9 celebrity suicides had significant impacts on suicide rates both in the total population and in the same gender- or the same age-subgroups. The incident that occurred in the 1990s had no significant impact on the overall suicide rates, whereas the majority of the incidents in the 2000s had significant influences for 30 or 60 days following each incident. The influence of celebrity suicide was shown to reach its peak following the suicide death of a renowned actress in 2008. The findings may suggest a link between media coverage and the impact of celebrity suicide. Future studies should focus more on the underlying processes and confounding factors that may contribute to the impact of celebrity suicide on subsequent suicide rates.

Etiquette for medical students' email communication with faculty members: a single-institution study.

BACKGROUND: Email is widely used as a means of communication between faculty members and students in medical education because of its practical and educational advantages. However, because of the distinctive nature of medical education, students' inappropriate email etiquette may adversely affect their learning as well as faculty members' perception of them. Little data on medical students' competency in professional email writing is available; therefore, this study explored the strengths and weaknesses of medical students' email etiquette and factors that contribute to professional email writing. METHODS: A total of 210 emails from four faculty members at Seoul National University College of Medicine were collected. An evaluation criteria and a scoring rubric were developed based on the various email-writing guidelines. The rubric comprised 10 items, including nine items for evaluation related to the email components and one item for the assessment of global impression of politeness. Three evaluators independently assessed all emails according to the criteria. RESULTS: Students were identified as being 61.0% male and 52.8% were in the undergraduate-entry program. The sum of each component score was 62.21 out of 100 and the mean value for global impression was 2.6 out of 4. The results demonstrated that students' email etiquettes remained low-to-mediocre for most criteria, except for readability and honorifics. Three criteria, salutation (r=0.668), closing (r=0.653), and sign-off (r=0.646), showed a strong positive correlation with the global impression of politeness. Whether a student entered a graduate-entry program or an undergraduate-entry program significantly contributed to professional email writing after other variables were controlled. CONCLUSIONS: Although students in the graduate-entry program demonstrated a relatively superior level of email etiquette, the majority of medical students did not write emails professionally. Educating all medical students in email etiquette may well contribute to the improvement of student-faculty relationships as well as their email writing.

Association between defense mechanisms and psychiatric symptoms in North Korean Refugees.

OBJECTIVE: Defense mechanism may contribute to psychiatric symptoms. Refugees are vulnerable to various psychiatric symptoms, such as depression, anxiety, somatization, and those associated with post-traumatic stress disorder (PTSD), due to their traumatic or stressful experiences. We aimed to investigate the mediating role of each defense mechanism in the occurrence of specific psychiatric symptoms in North Korean refugees. METHOD: Among 213 North Korean refugees initially recruited, 201 completed the following questionnaires: the Defense Style Questionnaire, the Center for Epidemiological Studies-Depression Scale (CES-D), the State-Trait Anxiety Inventory-State (STAI-S), the somatization subscale of Symptom Check-List-90-Revised (SCL-90-R), and the Impact of Event Scale-Revised (IES-R). Stepwise regression analysis was performed to determine the defense mechanisms more predominantly associated with specific psychiatric symptoms after controlling for age, sex, number of traumatic experiences, and other psychiatric symptoms (depressive symptoms and/or anxiety). RESULTS: Higher levels of depression were independently predicted by greater use of resignation. More use of acting out and less use of humor and sublimation independently predicted higher levels of anxiety. Somatization was independently predicted by more use of inhibition. PTSD symptoms were independently predicted by more use of undoing and isolation. CONCLUSIONS: Specific psychiatric symptoms were associated with specific defense mechanisms in North Korean refugees. Our findings suggest that the manifest psychiatric symptoms of refugees may be mediated by their dominant defense mechanism.

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.

Weekend catch-up sleep is independently associated with suicide attempts and self-injury in Korean adolescents.

The current study aims to determine the associations of insufficient sleep with suicide attempts and self-injury in a large, school-based Korean adolescent sample. A sample of 4553 middle- and high-school students (grades 7-10) was recruited in this study. Finally, 4145 students completed self-report questionnaires including items on sleep duration (weekday/weekend), self-injury, suicide attempts during the past year, the Suicidal Ideation Questionnaire (SIQ), and the Beck Depression Inventory (BDI). A multiple linear regression model showed that higher SIQ scores were associated with longer weekend catch-up sleep duration (p=0.009), higher BDI score (p<0.001), and longer time spent in a private educational institute (p=0.025). The multiple logistic regression analysis revealed that longer weekend catch-up sleep duration (p=0.011), higher BDI score (p<0.001), longer time spent in a private educational institute (p=0.046), and poorer academic record (p=0.029) were associated with suicide attempt and self-injury during the past year. The present results suggest that weekend catch-up sleep duration--which is an indicator of insufficient weekday sleep--might be associated with suicide attempts and self-injury in Korean adolescents.

Waking qEEG in older adults with insomnia and its associations with sleep reactivity and dysfunctional beliefs about sleep.

Sleep quality often deteriorates with age, and insomnia among the elderly increases the risks of both physical and psychiatric disorders. To elucidate the mechanisms and identify useful diagnostic biomarkers for insomnia in the elderly, the current study investigated the associations of waking brain activity patterns with susceptibility to stress-induced insomnia (sleep reactivity) and dysfunctional beliefs about sleep, major factors precipitating and maintaining insomnia, respectively. Forty-five participants aged 60 years or older with insomnia completed self-reported measures assessing depression, anxiety, sleep quality, dysfunctional beliefs about sleep, and sleep reactivity. Participants were then examined by quantitative electroencephalography (qEEG) during wakefulness, and spectral analysis was conducted to examine associations of regional frequency band power with these insomnia-precipitating and -maintaining factors. Dysfunctional beliefs about sleep were significantly correlated with higher beta/high-beta frequency band powers, while sleep reactivity was correlated with higher theta and delta frequency band powers. These findings suggest that sleep reactivity of older adults is associated with widespread cortical deactivation leading to poor stress coping, while their dysfunctional beliefs about sleep are associated with hyperactivation which is related to cognitive processes. These associations suggest that cognitive inflexibility and maladaptive stress-coping contribute to insomnia among the elderly.

Shift schedules and circadian preferences: the association with sleep and mood.

Object: We explored the circadian preferences of non-shift workers (non-SWs) and various types of shift workers (SWs), and the associations of these preferences with sleep and mood. Methods: In total, 4,561 SWs (2,419 women and 2,142 men aged 37.00 ± 9.80 years) and 2,093 non-SWs (1,094 women and 999 men aged 37.80 ± 9.73 years) completed an online survey. Of all SWs, 2,415 (1,079 women and 1,336 men aged 37.77 ± 9.96 years) reported regularly rotating or fixed schedules ("regular SWs"), and 2,146 (1,340 women and 806 men aged 36.12 ± 9.64 years) had irregular schedules ("irregular SWs"). Of the regular SWs, 2,040 had regularly rotating schedules, 212 had fixed evening schedules, and 163 had fixed night schedules. All participants completed the Morningness-Eveningness Questionnaire (MEQ) exploring circadian preferences, the short form of the Center for Epidemiological Studies-Depression Scale (CES-D) evaluating depression, the Insomnia Severity Index (ISI), and the Epworth Sleepiness Scale (ESS). Results: Compared to non-SWs, SWs had lower MEQ scores, i.e., more eveningness, after controlling for age, gender, income, occupation, and weekly work hours (F = 87.97, p < 0.001). Irregular SWs had lower MEQ scores than regular SWs (F = 50.89, p < 0.001). Among regular SWs, the MEQ scores of fixed evening and fixed night SWs were lower than those of regularly rotating SWs (F = 22.42, p < 0.001). An association between the MEQ and ESS scores was apparent in non-SWs (r = -0.85, p < 0.001) but not in SWs (r = 0.001, p = 0.92). Conclusion: SWs exhibited more eveningness than non-SWs; eveningness was particularly prominent in SWs with irregular or fixed evening/night shifts. Eveningness was associated with sleepiness only in non-SWs, but not in SWs.