Plasminogen Activator Inhibitor-1: Potential Inflammatory Marker in Late-life Depression

Objective@#Although several previous studies have examined the association between late-life depression and blood adipokine levels, a marker of chronic inflammation, no studies have comprehensively considered the effects of metabolic syndrome, which is known to affect blood adipokine levels. This study examined blood adipokine levels in geriatric depression after adjusting for the effects of metabolic syndrome. @*Methods@#Participants were selected from the Ansan Geriatric Study (depression group [n = 76] and control group [n = 76]). Blood concentrations of four adipokines (adiponectin, resistin, neutrophil-gelatinase-associated lipocalin [NGAL], and plasminogen activator inhibitor-1 [PAI-1]) were measured using immunoassays. The effects of blood adipokine concentration on the diagnosis of depression were analyzed using multivariate logistic regression to adjust for the effects of metabolic syndrome and potential confounding factors. @*Results@#When the effects of metabolic syndrome and potential confounding factors were adjusted, only PAI-1 could explain the diagnosis of depression among all the adipokines. The depression group showed a lower blood PAI-1 level than the control group. Adiponectin, resistin, and NGAL could not explain the diagnosis of depression when the effects of metabolic syndrome and potential confounding factors were adjusted. @*Conclusion@#This study suggests the possibility that the blood PAI-1 levels in clinically pathological late-life depression may show contrasting results to those with subclinical depressive symptoms. Additionally, considering that most previous studies have been conducted with pre-geriatric populations, the study suggests the possibility that geriatric depression may show inflammatory changes with patterns that are different from those of depression in the pre-geriatric population.

Neuromodulation for Insomnia Management / 수면정신생리

Hyperarousal or increased brain excitability is thought to play a key role in the pathophysiology of insomnia. Neuromodulation techniques are emergent complementary therapies for insomnia and can improve sleep by modulating cortical excitability. A growing body of literature support the idea that neuromodulation can be effective in improving sleep or treating insomnia. Recent evidence has revealed that neuromodulation methods can improve objective and subjective sleep measures in individuals with insomnia, although effects vary according to protocol. Different mechanisms of action might explain the relative efficacy of neuromodulation techniques on sleep outcomes. Further research testing different stimulation parameters, replicating existing protocols, and adding standardized sleep-related outcomes could provide further evidence on the clinical utility of neuromodulation techniques.

Insomnia in Emotional Labor: Its Role in Autonomic Nervous System Regulation

Objective@#The relation between female emotional laborers’ sleep quality and autonomic nervous system activity was investigated. @*Methods@#Thirty-three subjects’ heart rate variability (HRV) data and results of self-reported scale on sleep, depression, anxiety and suicidality, were collected. Subjects were classified into good sleeper (GS) and poor sleeper (PS) groups relying on sleep quality. Changes of HRV between working time and resting time in each group were compared. @*Results@#The PS group showed significantly lower difference in root mean square of successive differences (RMSSD), percentage of successive normal-to-normal intervals that differ by more than 50 ms (pNN50), and natural logarithm high-frequency (LnHF) when they were working as compared to when they were resting, which means decreased function of the parasympathetic nervous system (PNS). Repeated measures analysis of covariance showed that the group effect was significant only for LnHF, with score of depression scale as a covariate. @*Conclusion@#Female emotional laborers who complain of sleep difficulty may have decreased function of the PNS. Therefore, good sleep quality is essential for maintaining and promoting mental and physical health of women engage in emotional labor.

Neuromodulation for Insomnia Management / 수면정신생리

Hyperarousal or increased brain excitability is thought to play a key role in the pathophysiology of insomnia. Neuromodulation techniques are emergent complementary therapies for insomnia and can improve sleep by modulating cortical excitability. A growing body of literature support the idea that neuromodulation can be effective in improving sleep or treating insomnia. Recent evidence has revealed that neuromodulation methods can improve objective and subjective sleep measures in individuals with insomnia, although effects vary according to protocol. Different mechanisms of action might explain the relative efficacy of neuromodulation techniques on sleep outcomes. Further research testing different stimulation parameters, replicating existing protocols, and adding standardized sleep-related outcomes could provide further evidence on the clinical utility of neuromodulation techniques.

Insomnia in Emotional Labor: Its Role in Autonomic Nervous System Regulation

Objective@#The relation between female emotional laborers’ sleep quality and autonomic nervous system activity was investigated. @*Methods@#Thirty-three subjects’ heart rate variability (HRV) data and results of self-reported scale on sleep, depression, anxiety and suicidality, were collected. Subjects were classified into good sleeper (GS) and poor sleeper (PS) groups relying on sleep quality. Changes of HRV between working time and resting time in each group were compared. @*Results@#The PS group showed significantly lower difference in root mean square of successive differences (RMSSD), percentage of successive normal-to-normal intervals that differ by more than 50 ms (pNN50), and natural logarithm high-frequency (LnHF) when they were working as compared to when they were resting, which means decreased function of the parasympathetic nervous system (PNS). Repeated measures analysis of covariance showed that the group effect was significant only for LnHF, with score of depression scale as a covariate. @*Conclusion@#Female emotional laborers who complain of sleep difficulty may have decreased function of the PNS. Therefore, good sleep quality is essential for maintaining and promoting mental and physical health of women engage in emotional labor.

Emotional Changes and Protective Factors of Emotional Workers in the Public and Private Sector

Objective@#Emotional labor is known to be a risk factor for emotional distress. This study aimed to evaluate specific stressors according to the type of occupation and identify protective and adverse factors. @*Methods@#We recruited 349 workers engaged in emotional labor in a suburban city. They were assessed using scales regarding emotional status, job stress, resilience, and job satisfaction. Correlation and regression analyses were performed to evaluate their emotional state according to their stress level. A mediation model using structural equation modeling was utilized to identify the mediating effects of resilience and workplace satisfaction. @*Results@#The correlation analysis indicated that the level of workplace stress was statistically correlated with depressed mood and anxiety and showed a significant inverse correlation with individuals’ resilience and job satisfaction. According to the regression analysis, in private institution workers, “emotional disharmony and hurt” had a statistically significant negative effect on their emotional state, and in public institution workers, “emotional demands and regulation” were prominent. Resilience partially mediated the relationship between emotional stress and anxiety/depressive symptoms. @*Conclusion@#Our findings indicate that the causes of stress differed according to the working environment. Preventive strategies such as resilience training and relieving stress on individual factors are needed to promote mental health.

A Preliminary Study for Translation and Validation of the Korean Version of The Cognitive, Affective, and Somatic Empathy Scale in Young Adults

OBJECTIVE: The cognitive, Affective, and Somatic Empathy Scale (CASES) suggests novel three components structure of empathy. Although CASES developed to assess the trait empathy of both children and adult, the validation in adult sample is not yet conducted. This study developed Korean version of CASES (CASES-K) and examined the psychometric properties in young adult for first time. METHODS: Confirmatory factor analysis was conducted to test whether the factor structure suggested in initial development study is valid in Korean young adult population. 350 young adults participated, and 44 of them also answered to other empathy scales for validation. The construct validity was ascertained through a series of correlational analysis with widely used trait empathy scales. RESULTS: The result of confirmatory factor analysis supports the three-factor model of empathy consists of affective, cognitive and somatic facets. The construct validity was ascertained through a series of correlational analysis with widely used trait empathy scales. The result of correlational analysis supports the validity of CASES-K, and especially the separation of somatic empathy from affective empathy. CONCLUSION: The current study provides the first evidence of the validity and utility of the CASES-K in young adult population. The result also supports the commonality of three factor structure of empathy in both East Asian and Caucasian, from the children to adults.

Comparison of the Usefulness of the PHQ-8 and PHQ-9 for Screening for Major Depressive Disorder: Analysis of Psychiatric Outpatient Data

OBJECTIVE: This study aimed to demonstrate that the Patient Health Questionnaire (PHQ)-8 is not less useful than the PHQ-9 as a screening test for major depressive disorder (MDD). METHODS: We performed a retrospective analysis of 567 patients in psychiatric outpatient units. The Mini International Neuropsychiatric Interview was used to diagnose MDD. We derived the validity and reliability of the PHQ-8 and PHQ-9. To evaluate the ability of the PHQ-8 and PHQ-9 to discriminate MDD, we drew receiver operating characteristic (ROC) curves and compared the areas under the curves (AUCs). RESULTS: Of the 567 participants, 207 (36.5%) were diagnosed with MDD. Cronbach’s αs for the PHQ-8 and PHQ-9 were 0.892 and 0.876, respectively. Similar to the PHQ-9, the PHQ-8 was also associated with scores on the Hamilton Depression Rating Scale in a correlation analysis. When we drew ROC curves for the PHQ-8 and PHQ-9, there was no statistically significant difference in the AUCs. With a cutoff score of 10, the PHQ-8 showed a sensitivity of 58.3%, specificity of 83.1%, positive predictive value of 53.4%, and negative predictive value of 85.7%. CONCLUSION: In a psychiatric outpatient sample, the PHQ-8 was as useful as the PHQ-9 for MDD screening.

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.

Characteristics of Residual Symptoms in Korean Patients with Major Depressive Disorder: A Validation Study for the Korean Version of Depression Residual Symptom Scale

OBJECTIVE: Residual symptoms of depression are related to more severe and chronic course of functional impairment with higher risk of relapse. The objective of this study was to validate, and determine psychometric properties of the Korean version of Depression Residual Symptom Scale (KDRSS). METHODS: A total of 203 outpatients with recent episode of major depression based on DSM-IV criteria were enrolled in this study. They had been treated with antidepressants and assessed by KDRSS, Hamilton Depression Rating Scale-24 (HDRS-24), and Montgomery-Åsberg Depression Rating Scale (MARDS). The validity and reliability of KDRSS were assessed, including internal consistency reliability, concurrent validity, temporal stability, factorial validity, and discriminative validity. RESULTS: Internal consistency (Cronbach’s alpha=0.961), concurrent validity (MADRS: r=0.731, p < 0.01, HDRS-24: r=0.663, p < 0.01), and temporal stability (r=0.726, p < 0.01) of KDRSS were all excellent. KDRSS showed good discriminative validity based on MARDS. KDRSS consisted of one-factor structure accounting for 63.8% of total variance. All subjects except two in full remission group had one or more residual symptoms. In 7 subscales of KDRSS consisting of similar items respectively, ‘lack of energy’ was the most commonly reported, followed by ‘increased emotionalism’ in this group. CONCLUSION: KDRSS is a useful and sensitive instrument for measuring residual depressive symptoms. Since some depressive symptoms including ‘lack of energy’ and ‘increased emotionalism’ in patients with full remission might be persistent during psychiatric intervention, these symptoms need to be focused on in clinical practice.

Natural Course of Posttraumatic Symptoms in Late-Adolescent Maritime Disaster Survivors: Results of A 12-Month Follow-Up Study

OBJECTIVE: This study is a prospective observational study on 75 late-adolescent survivors of a large passenger ship accident from immediately after the accident to one year later. METHODS: Assessments of student survivors were conducted on day 2 and at months 1, 6, and 12. The PTSD Checklist (PCL), Patient Health Questionnaire-9 (PHQ-9), State subscale of the State and Trait Anxiety Inventory (STAI-S), Athens Insomnia Scale (AIS), and Brief Resilience Scale (BRS) were administered. RESULTS: When the assessments for day 2 and month 12 were compared, all the scales, except the PCL-avoidance subscale, showed a significant improvement in symptoms among males. However, among females, all the scales, except the PCL-re-experience subscale and the STAI-S, failed to show a significant improvement. All the symptoms for both males and females showed a pattern that decreased to the lowest level at month 1 (camp-based controlled intervention period), then increased at months 6 and 12 (voluntary individual treatment after returning to school). CONCLUSION: The rapid deterioration of psychological symptoms was found during the chronic phase, when students returned to their daily routines and received voluntary individual therapy. There is a need to screen high-risk adolescents and be more attentive to them during this period.

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 rapid eye movement (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.

Eye Movement Desensitization and Reprocessing to Facilitate Posttraumatic Growth: A Prospective Clinical Pilot Study on Ferry Disaster Survivors

OBJECTIVE: The purpose of this study was to investigate the therapeutic effects of eye movement desensitization and reprocessing (EMDR) on post-traumatic growth (PTG). METHODS: This study was conducted using a sample of ten survivors of a large-scale maritime disaster that occurred in the Yellow Sea, South Korea, in April 2014. A total of eight EMDR sessions were administered by a psychiatrist at two-week intervals over a period of five months, starting two or three months after the accident. Post-Traumatic Growth Inventory (PTGI), Stress-Related Growth Scale (SRGS), Clinician-Administered PTSD Scale (CAPS), and Connor-Davidson Resilience Scale (CD-RISC) were measured before treatment, after sessions 4 and 8, and at three months after treatment completion. RESULTS: After three months from treatment completion, significant increases were observed in PTG (PTGI: Z(8)=−2.380, p=0.017; SRGS: Z(8)=−2.380, p=0.017) and resilience (CD-RISC: Z(8)=−2.386, p=0.017). A decrease in post-traumatic stress disorder (PTSD) level was also significant (CAPS: Z(8)=−2.176, p=0.030). The reduction of CAPS scores was correlated with increases of PTGI (rho=0.78, p=0.023) and SRGS (rho=0.79, p=0.020) scores. The changes in CAPS, PTGI, and SRGS scores between time point of end 8-session and three months follow-up was not significant (all p>0.05). Subjects with higher pre-treatment CD-RISC scores showed more significant improvements in PTGI (rho=0.88, p=0.004) and SRGS (rho=0.83, p=0.010) scores after treatment than did those with lower pre-treatment CD-RISC scores. CONCLUSION: EMDR therapy using standard protocol for trauma processing helped facilitating PTG in disaster survivors. To generalize these findings, further controlled studies comparing with other treatment modalities for PTSD are needed.

Measurement-based Treatment of Residual Symptoms Using Clinically Useful Depression Outcome Scale: Korean Validation Study

OBJECTIVE: This study was aimed at evaluating the diagnostic validity of the Korean version of the Clinically Useful Depression Outcome Scale (CUDOS) with varying follow-up in a typical clinical setting in multiple centers. METHODS: In total, 891 psychiatric outpatients were enrolled at the time of their intake appointment. Current diagnostic characteristics were examined using the Structured Clinical Interview for DSM-IV (41% major depressive disorder). The CUDOS was measured and compared with three clinician rating scales and four self-report scales. RESULTS: The CUDOS showed excellent results for internal consistency (Cronbach's α, 0.91), test-retest reliability (patients at intake, r=0.81; depressed patients in ongoing treatment, r=0.89), and convergent and discriminant validity (measures of depression, r=0.80; measures of anxiety and somatization, r=0.42). The CUDOS had a high ability to discriminate between different levels of depression severity based on the rating of Clinical Global Impression for depression severity and the diagnostic classification of major depression, minor depression, and non-depression. The ability of the CUDOS to identify patients with major depression was high (area under the receiver operating characteristic curve=0.867). A score of 20 as the optimal cutoff point was suggested when screening for major depression using the CUDOS (sensitivity=89.9%, specificity=69.5%). The CUDOS was sensitive to change after antidepressant treatment: patients with greater improvement showed a greater decrease in CUDOS scores (p<0.001). CONCLUSION: The results of this multi-site outpatient study found that the Korean version of the CUDOS is a very useful measurement for research and for clinical practice.

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.

A Study for Link of Institution in Disaster Management : Ansan District Study / 정신신체의학

OBJECTIVES: The management of disaster should be immediate and sustainable. Further, it is hard to predict where the disaster will occur, using pre-exists governmental and non-governmental organizations are important. In this study, we tried to investigate the associated activities of organizations performed in Ansan city, in Sewol ferry accident. METHODS: A total 121 workers in 25 organizations were surveyd about organizations which they worked with, kind of works performed, frequency of meetings, satisfaction in activities and factors associated with dissatisfaction in usual state and in Sewol ferry accident state, respectively. The differences between those two situations were analyzed using paired t-test for continuous variables and Chi-square test or McNemar test for categorical variables. RESULTS: The total number of linkage of institutions were decreased(from n=397 to n=251) and the mean scores of rating satisfaction were significantly lower in most of organizations in disaster state. The rigid policy in performance evaluation was more likely associated with dissatisfaction in disaster state than usual state(p=0.045). CONCLUSIONS: For effective linkage of institutions, preparedness, such as understanding the capability of organizations in the communities and developing the protocol for associated activities, is important. The unnecessary and effortful performance evaluation should be sublated.

Amisulpride Switching in Schizophrenic Patients Who Showed Suboptimal Effect and/or Tolerability to Current Antipsychotics in a Naturalistic Setting: An Explorative Study

OBJECTIVE: Despite numerous atypical antipsychotics (AAP) available, many patients with schizophrenia still experience lack of efficacy and persistent side-effects. Switching from one AAP to another with a different side-effect profile has become a common clinical strategy. We aimed to investigate effect of switching to amisulpride in patients who showed suboptimal effect and/or tolerability to current antipsychotics treatment. METHODS: This was a 6-week, prospective, multicenter, open-label, flexible-dose study in patients with schizophrenia. Switching to amisulpride was achieved using cross-titration within 7 days (day 1: 300 mg on day 1 then flexibly dosed 400–800 mg/day). The primary end-point measure was proportion of patients achieving improvement in clinical benefit at week 6 based on Clinical Global Impressions-Clinical Benefit (CGI-CB). Secondary endpoints included change in scores in CGI-CB, CGI-Severity (CGI-S), Subjective Satisfaction Scores (SSS), Brief Psychiatric Rating Scale (BPRS), and Simpson and Angus Rating Scale. RESULTS: Among 37 patients switched to amisulpride, 76% completed study and 56.8% had clinical benefit measure by CGI-CB. CGI-CB and CGI-S scores showed significant improvement at week 6 compared to baseline (mean changes of CGI-CB and CGI-S scores: −1.7+1.0, p<0.0001 and −0.6±0.0, p=0.001, respectively). SSS scores also improved significantly (mean change: 2.1±2.6, p<0.0001). Mean weight of patients significantly lowered compared to baseline (mean change: −1.2±2.0, p<0.0001). CONCLUSION: Patients with schizophrenia who showed suboptimal efficacy or tolerability with their current antipsychotics and thereby switched to amisulpride resulted in clinical benefit in terms of both improved efficacy and tolerability. The small sample size limits generalizability of the study results.

Recurrence of Panic Attacks after Influenza Vaccination: Two Case Reports

Human influenza is a contagious respiratory illness caused by the influenza virus. The influenza vaccination is recommended annually, but several adverse effects related to allergic reactions have been reported. Panic attacks are also known to occur, but no case of a panic attack adverse effect has been reported in South Korea. We present two cases of panic disorder patients whose symptoms were aggravated by the influenza vaccination. We assumed that dysregulation of T-lymphocytes in panic disorder patients could have a role in activating various kinds of cytokines and chemokines, which then can lead to panic attack aggravation.

Frontoparietal Cortical Thinning in Respiratory-Type Panic Disorder: A Preliminary Report

OBJECTIVE: Many evidences raise the possibility that the panic disorder (PD) patients with respiratory subtype (RS) may have characteristic structural abnormalities. We aimed to explore the structural differences between PD patients with and without the respiratory symptoms. METHODS: Patients with PD were recruited from the Department of Psychiatry at Korea University Anam Hospital. Respiratory subtype (RS) was diagnosed when at least 4 out of 5 of the following respiratory symptoms were present during the panic attack: fear of dying, chest pain/discomfort, shortness of breath, paresthesias, and a choking sensation. We acquired high-resolution MRI scans and used FreeSurfer to obtain a measure of cortical thickness for each patient. RESULTS: Cluster based analysis revealed significantly decreased cortical thickness in the left hemisphere in the caudal-middle-frontal, superior frontal, and posterior parietal areas in the RS group. No significant difference was observed in any of the limbic areas. CONCLUSION: Respiratory symptoms of panic disorder were associated with a reduction in cortical thickness in the left frontal and parietal areas. This finding leads to the assumption that the frontoparietal network is the crucial component in a larger cortical network underlying the perception of dyspnea in RS.

Sleep and Suicide / 수면정신생리

Previous research has identified the biological, psychological, and social factors that confer an elevated risk for suicide. Evidence suggests that sleep disturbances are one of the risk factors that predict an increased risk for suicidal behaviors. Both sleep disorders and general sleep complaints are linked to higher levels of suicidal ideation and depression, as well as increased rates of suicide and suicide attempts. The causal mechanism of this association is not clear. For example, it is not known if insomnia is an independent phenomenon that if interrupted could prevent the emergence of a mental disorder, or if insomnia is a symptom of another developing illness. Hypofrontality, HPA dysfunction, and an impaired serotonergic system are potential mechanisms underlying the association of sleep disturbances and suicidal behavior. Future research is necessary to examine the specific mechanism of this association between sleep and suicide, which may lead to an effective intervention and diminished suicide risk.