In Hee Cho

Insufficient sleep and suicidality in adolescents.

STUDY OBJECTIVES To investigate the association between the behaviorally induced insufficient sleep and suicidality among adolescents. DESIGN A population-based, cross-sectional survey. SETTING General community. PARTICIPANTS A sample of 8,530 students (grades 7-11) was recruited in the Republic of Korea. The participants were 8,010 students who completed all questionnaires. INTERVENTION N/A. MEASUREMENTS The survey included the Beck Scale for Suicidal Ideation (SSI), the Beck Depression Inventory (BDI), a modified Epworth Sleepiness Scale (ESS), and questionnaires about sleep (weekday/weekend sleep schedule/duration, insomnia and snoring). RESULTS Adolescents with behaviorally induced insufficient sleep syndrome (BISS) had higher SSI scores than those who slept ≥ 7 hours on weekdays, even after controlling for age, sex, and BDI score (F = 11.71, P < 0.001). After controlling for age and sex, longer weekend oversleep and shorter weekday sleep duration predicted a higher SSI score (β = 0.19, P < 0.001; β = 0.37, P < 0.001). The association between weekend oversleep and SSI score remained significant even after additionally controlling for BDI and ESS scores and presence of insomnia and snoring (β = 0.07, P < 0.01). CONCLUSION BISS was found to be associated with increased suicidality. Weekend oversleep was associated with suicidality independently of depression, daytime sleepiness, snoring, and insomnia. The study findings suggest that chronic sleep restriction among adolescents may increase suicidal risk.

The relationship between psychotic-like experiences and sleep disturbances in adolescents

OBJECTIVE We investigated the relationships between sleep disturbances and psychotic-like experiences (PLEs) among adolescents. METHODS A total of 8530 students (grades 7-11) were recruited in the Republic of Korea, and 7172 students who completed all of the relevant questionnaires participated in the current study. The survey included the Eppendorf Schizophrenia Inventory (ESI), the Youth Psychosis At Risk Questionnaire (Y-PARQ), the Beck Depression Inventory (BDI), the Epworth Sleepiness Scale and questionnaires about sleep disturbances (insomnia, cataplexy and snoring). RESULTS Subjects with insomnia, excessive daytime somnolence (EDS), or probable cataplexy had higher ESI and Y-PARQ scores after controlling for age, sex and BDI scores (all p<0.001). Insomnia (OR=4.40), EDS (OR=3.84) and probable cataplexy (OR=2.97) predicted clinical high risk of psychosis. Insomnia, EDS and probable cataplexy remained as significant predictors of clinical high risk for psychosis, even after controlling for depressive symptoms or when analyses were confined to non-depressive adolescents. CONCLUSIONS Insomnia and EDS were found to predict PLEs in adolescents, independent of depression. Our findings suggest that adolescents complaining of insomnia or sleepiness may require further assessment regarding potential risk of psychosis.

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.

Risk factors for suicidal ideation of the general population

The aim of this study was to investigate risk factors of suicide ideation in general population. A total of 1,116 adults were sampled with randomization in an urban area. After excluding 116 participants due to incomplete answer, 1,000 participants (500 males; mean age 39.6 ± 11.6) completed self-report questionnaire including the Center for Epidemiologic Study Depression Scale (CES-D), the Beck Scale for Suicide Ideation (BSI), the Spielberger State-Trait Anger Expression Inventory (STAXI), the Barratt Impulsiveness Scale (BIS), and questions on weekday sleep duration. Results showed higher scores on the BSI were related with higher scores on the STAXI, CES-D, a family history of psychiatric illness, and short or long sleep duration (≤ 5 or ≥ 10 hr) (adjusted R2 = 0.151, P < 0.001, P < 0.001, P = 0.001, and P = 0.008, respectively). The predictive power of the STAXI scores, the presence of psychiatric family history and short or long sleep duration was stronger in the high CES-D group with scores of 16 or higher (adjusted R2 = 0.275, P < 0.001, P < 0.001, and P < 0.001, respectively). These findings suggest that suicide idea in general population may be related with the presence of family history for psychiatric illness, depressive mood, high anger and short or long sleep duration.

Gender difference in the association between adult attention deficit hyperactivity disorder symptoms and morningness–eveningness.

We aimed to investigate the association between attention deficit hyperactivity disorder (ADHD) and morningness–eveningness in adulthood. Subjects without psychiatric comorbidity on the Structured Clinical Interview for DSM‐IV Axis I Disorders (n = 344) completed the Morningness–Eveningness Questionnaire (MEQ) and the Adult Self‐Report Scale for ADHD. MEQ showed an independent and negative association with ADHD symptoms (P < 0.0001). In male subjects, both inattention (P < 0.0001) and hyperactivity–impulsivity were associated with MEQ (P = 0.01). In female subjects, only inattention was associated with MEQ (P < 0.001). Our findings suggest that eveningness may be strongly associated with inattention of adult ADHD and that it may be associated with hyperactivity–impulsivity of adult ADHD in male subjects only.

Interaction between Brain-Derived Neurotrophic Factor Val66Met Polymorphism and Recent Negative Stressor in Harm Avoidance

There have been controversial results regarding the association between brain-derived neurotrophic factor (BDNF) Val66Met polymorphism and anxiety-related traits such as harm avoidance (HA). We aimed to investigate the interaction between BDNF Val66Met polymorphism and negative life stressors in HA. BDNF Val66Met polymorphism was genotyped in 391 community-dwelling Koreans (152 males, 239 females; 43.2 ± 14.1 years old). The Temperament and Character Inventory (TCI) and the Center for Epidemiological Studies for Depression Scale (CES-D) were self applied. The Structured Clinical Interview for DSM-IV axis I disorders and face-to-face interviews investigating negative life stressors within the last 6 months were also performed. There was no significant difference in TCI score, major depressive disorder prevalence and CES-D score among the 3 genotypes (94 Met/Met, 188 Val/Met and 109 Val/Val subjects). There was no significant difference in TCI scores between subjects with stressors and those without stressors, while more common major depressive episodes (p = 0.03) and higher CES-D scores (p < 0.001) were found in subjects with stressors. However, there was a significant interaction between the BDNF genotype and negative life stressors in HA (p = 0.02). Only subjects with the Val/Val genotype showed higher HA with recent negative stressors. Our finding suggests that BDNF Val66Met polymorphism might influence HA by interacting with recent negative stress experience.

Direct and indirect effects of the temperament and character on alexithymia: a pathway analysis with mood and anxiety

OBJECTIVE We aimed to assess the pathway from personality to alexithymia through mood and anxiety as mediators. METHOD Three hundred thirty-four subjects (130 male), whose psychiatric health was verified by Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I disorders, completed the Toronto Alexithymia Scale-20 (TAS-20), the Temperament and Character Inventory, the State-Trait Anxiety Inventory (STAI), and the Center for Epidemiological Studies-Depression scale (CES-D). The schematic models for the pathway analysis from Temperament and Character Inventory (TCI) to TAS-20 scores were made. RESULTS Low reward dependence (RD), low self-directedness (S-D), and high cooperativeness (CO) had paths to TAS-20 total (P = .000, P = .000, and P = .042, respectively). S-D had also an indirect path via STAI-state to TAS total. On TAS-20 factor 1, low RD, low S-D, and high self-transcendence (ST) had direct effects (P = .004, P = .000, and P = .000, respectively). S-D had also an indirect path via STAI-state and (CES-D) on TAS-20 factor 1. On TAS factor 2, low novelty seeking (NS), high harm avoidance (HA), low RD, low S-D, and high cooperativeness (CO) had direct effects (P = .005, P = .011, P = .000, P = .000, and P = .004, respectively). On TAS-20 factor 3, low RD and S-D had direct effects (P = .002 and P = .000, respectively). CONCLUSION Current results suggest that although alexithymia is affected by the personality, state-dependent mood and anxiety may mediate the relationship between alexithymia and personality.

Psychotic-like experiences and their relationship to suicidal ideation in adolescents

Studies have suggested that psychotic-like experiences (PLEs) are associated with behavioral problems in adolescents. The aim of this study was to investigate relationships between domains of PLEs, suicidal ideation, and depression in a large community sample of adolescents. The sample consisted of 8096 Korean subjects (3184 boys and 4912 girls) aged 14 to 19 years. The level of PLEs, depression, and suicidal ideation were assessed by the Eppendorf schizophrenia inventory (ESI), Becks depression inventory, and Becks scale for suicidal ideation, respectively. Both the level of depression and suicidal ideation were significantly associated with PLEs. Among the four domains of the ESI, the deviant perception, ideas of reference, and auditory uncertainty were associated with the suicidal ideation. Additionally, subjects with more PLEs had significantly more suicidal ideation and depressive symptoms. PLEs in adolescents are associated with potential risk of suicide and depressive symptoms significantly mediated the association between suicidal ideation and PLEs. The presence of perceptual disturbances, ideas of reference, and depression may be regarded as warning signs for suicide-related behaviors.

The relationship between psychotic-like experiences and attention deficits in adolescents

OBJECTIVE The present study focused on the relationship between psychotic-like experiences (PLEs) and attention deficits in adolescents. METHODS A total of 2325 students, ages 14-19 years, across eight high schools in the Republic of Korea were recruited. Students performed the computerized Comprehensive Attention Test (CAT), which measures sustained and divided attention, and completed the Eppendorf Schizophrenia Inventory (ESI) and Beck Depression Inventory (BDI). One hundred sixty-six participants were excluded from the present study due to incomplete answers on the ESI; thus, data from 2159 students were included in the final analysis. RESULTS Higher ESI scores predicted more omission and commission errors in divided-attention tasks after controlling for age, sex, and depressed mood (p = 0.024; p = 0.001, respectively). Attention and speech impairments on the ESI were the most frequent predictors of an increased number of errors in the attention tasks. All four ESI domains predicted the number of commission errors in divided-attention tasks (p < 0.001, p = 0.040, p = 0.046, and p = 0.013, respectively). In the high-risk group for psychosis (ESI ≥ 29), higher scores on the ideas of reference subscale were significantly associated with a higher number of both omission and commission errors in divided-attention tasks (p = 0.006, p = 0.017, respectively). CONCLUSIONS PLEs during adolescents were associated with impaired attention on the divided-attention task, which demands increased attentional effort. Attention deficits in adolescents prone to psychosis may be related to thought-content disturbances rather than to cognitive and perceptual symptoms.

Association between morningness-eveningness and temperament and character in community-dwelling Korean adults

Previous studies have reported an association between biogenetic temperament/character and circadian preference in Spanish or French college students. Our aim is to investigate the association between temperament/character and circadian preference in psychiatrically healthy, community‐dwelling Korean adults of a wide age range.