Sleep quality, posttraumatic stress, depression, and human errors in train drivers: a population-based nationwide study in South Korea

Psychosocial hazards, posttraumatic stress disorder, complex posttraumatic stress disorder, depression, and anxiety in the U.K. rail industry: A cross-sectional study

This study examined posttraumatic stress disorder (PTSD), complex PTSD, depression, and anxiety among U.K. rail workers. A cross-sectional survey examining exposure to seven psychosocial hazards (bullying/harassment; verbal abuse; physical and sexual assault; and hearing about, seeing the aftermath of, or witnessing a fatality), working conditions, physical health, and the impact of COVID-19 was administered to 3,912 participants. Outcome measures were the ITQ, PHQ-9, and GAD-7. Among trauma-exposed participants, 24.3% met the criteria for PTSD or CPTSD; 38.6% and 29.2% of all participants scored in the moderate-to-severe range on the PHQ-9 and GAD-7, respectively. Data were analyzed using logistic and linear regression. Bullying/harassment was positively associated with GAD-7 scores, f² = .001, and PTSD and CPTSD, ORs = 1.83-2.02. Hearing about and witnessing a fatality were associated with PTSD and CPTSD, ORs = 1.77-2.10. Poorer ergonomics at work were positively associated with PHQ-9 and GAD-7 scores, f² = .001. Higher job satisfaction was associated with lower odds of PTSD and CPTSD, ORs = 0.87-0.91, and negatively associated with PHQ-9 and GAD-7 scores, f² = .008-.01. Work intensity was associated with PTSD and CPTSD, ORs = 1.79-1.83, and positively associated with PHQ-9 and GAD-7 scores, f² = .02-.03. Reporting more physical health problems was associated with PTSD, OR = 1.07, and positively associated with GAD-7 and PHQ-9 scores, f² = .008-.01. The results suggest bullying/harassment and work intensity are important variables in employee mental health and could drive future research and industry initiatives.

Measuring the effects of mind wandering in people with insomnia: A driving simulator study

Purpose

Studies have shown that individuals with insomnia experience more frequent and longer episodes of mind wandering (MW) while driving. However, the effect of the interaction between insomnia and MW on driving behavior is not fully understood. This study aimed to gain deeper insights into the relationships among insomnia, MW, and driving behavior.

Patients and methods

Forty-two participants (21 diagnosed with insomnia and 21 controls) were recruited, and subjective sleep quality and cognitive function were assessed. A driving simulator experiment with a within-subject design was performed, involving two distraction tasks (no-distraction task versus MW task) and two driving scenarios (lane-keeping versus lane-changing).

Results

In the lane-keeping scenario, there was no significant between-group difference (people with insomnia and controls) in longitudinal driving performance for the no-distraction task, although the interaction between MW and insomnia significantly increased drivers’ longitudinal control variation. Correlation analysis confirmed that longitudinal driving performance was positively correlated with sleep quality and the cognitive level. Unlike longitudinal driving performance, lateral driving performance was significantly weaker in people with insomnia than in controls under both distraction tasks. In the lane-changing scenario, although there was no between-group difference in driving performance, the MW task led to significant changes in driving performance within each group compared with the no-distraction task, and these findings were associated with cognitive function, but not with sleep quality.

Conclusion

These findings show that insomnia and MW combined can lead to reduced driving performance. Further research is needed to elucidate the factors that influence this phenomenon.

Sleeping, sleeping environments, and human errors in South Korean male train drivers

Objectives

Reducing human errors caused by daytime sleepiness among train drivers is important to prevent train accidents. Our purpose of the study was to investigate the association among sleep, workplace sleeping environments, and human errors.

Methods

We recruited 144 South Korean train drivers belongs to the Korean Railroad Corporation. This cross‐sectional data was analyzed to investigate the association of insomnia (insomnia severity index), sleep quality (Pittsburgh sleep quality index), obstructive sleep apnea (Berlin questionnaire), and daytime sleepiness (Epworth scale) with human error and near‐miss experiences. We examined whether human error and near‐miss events were associated with various sleeping environments at work and at home after adjusting for the sleep indices.

Results

The experience of human errors was associated with insomnia and daytime sleepiness, and near‐miss events were associated with insomnia among South Korean drivers. Sleeping environments including cold temperature and odor were related to both human errors and near‐miss events among South Korean train drivers, after adjusted for age, working years, shiftwork, obesity, smoking, binge drinking, regular exercise, caffeine consumption, sleep quality, severity of insomnia, obstructive sleep apnea, and daytime sleepiness.

Conclusions

The train drivers’ workplace sleeping environment is significantly associated with human error events and near‐miss events after adjusting for sleep quality, insomnia, obstructive sleep apnea, and daytime sleepiness. To prevent train accidents caused by human errors, more attention is necessary for improving workplace sleeping environments.

Workaholism and negative work-related incidents among nurses

The present study comprised 1,781 nurses who participated in an investigation about working conditions, sleep, and health. They answered a questionnaire about age, sex, marital status, children living at home, work hours per week, number of night shifts last year, and total sleep duration and that also included a validated instrument assessing workaholism. In addition, they were asked to report on eight items concerning negative work-related incidents (dozed off at work, dozed while driving, harmed or nearly harmed self, harmed or nearly harmed patients/others, and harmed or nearly harmed equipment). Logistic regression analyses identified several predictors of these specific incidents: Low age (dozed at work, harmed and nearly harmed self, harmed and nearly harmed equipment), male sex (harmed and nearly harmed self, nearly harmed equipment), not living with children (harmed patients/others), low percentage of full-time equivalent (nearly harmed self and harmed patients/others), number of night shifts last year (dozed off at work and while driving, nearly harmed patients/others) and sleep duration (inversely related to dozed off at work and while driving, nearly harmed self). However, the most consistent predictor of negative work-related incidents was workaholism which was positively and significantly associated with all the eight incidents.

Correlation of occupational stress with depression, anxiety, and sleep in Korean dentists: cross-sectional study

BACKGROUND

This study aimed to investigate the degree of occupational stress and the clinical mental state of dentists. In addition, we investigated the correlation of occupational stress with depression, anxiety, and sleep among dentists in Korea.

METHODS

A cross-sectional survey on 231 dentists was conducted using the Doctor Job Stress Scale, Center for Epidemiologic Studies Depression Scale (CES-D), State-Trait Anxiety Index (STAI), and Pittsburgh Sleep Quality Index (PSQI). Correlation of occupational stress with mental health was investigated by adjusted multiple regression analysis.

RESULTS

The scores of CES-D, STAI, and PSQI revealed a significant correlation with the Doctor Job Stress Scale (t = 3.93, P < 0.0001; t = 4.05, P < 0.0001; t = 4.18, P < 0.0001, respectively). In particular, patient factors and clinical responsibility/judgment factors were significantly associated with depression (t = 2.80, P = 0.0056; t = 4.93, P < 0.0001, respectively), anxiety (t = 2.35, P = 0.0195; t = 5.11, P < 0.0001, respectively), and sleep (t = 3.78, P = 0.0002; t = 4.30, P < 0.0001, respectively), whereas work factors were not associated with any mental health state.

CONCLUSIONS

This study confirms that dentists as professions experience more severe mental states. For successful mental health care among dentists, stress management focusing on interpersonal relationship with patients and responsibility as an expert rather than the intensity of work should be considered.

Effects of smartphone use with and without blue light at night in healthy adults: A randomized, double-blind, cross-over, placebo-controlled comparison

Smartphones deliver light to users through Light Emitting Diode (LED) displays. Blue light is the most potent wavelength for sleep and mood. This study investigated the immediate effects of smartphone blue light LED on humans at night. We investigated changes in serum melatonin levels, cortisol levels, body temperature, and psychiatric measures with a randomized, double-blind, cross-over, placebo-controlled design of two 3-day admissions. Each subject played smartphone games with either conventional LED or suppressed blue light from 7:30 to 10:00PM (150 min). Then, they were readmitted and conducted the same procedure with the other type of smartphone. Serum melatonin levels were measured in 60-min intervals before, during and after use of the smartphones. Serum cortisol levels and body temperature were monitored every 120 min. The Profile of Mood States (POMS), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and auditory and visual Continuous Performance Tests (CPTs) were administered. Among the 22 participants who were each admitted twice, use of blue light smartphones was associated with significantly decreased sleepiness (Cohen's d = 0.49, Z = 43.50, p = 0.04) and confusion-bewilderment (Cohen's d = 0.53, Z = 39.00, p = 0.02), and increased commission error (Cohen's d = -0.59, t = -2.64, p = 0.02). Also, users of blue light smartphones experienced a longer time to reach dim light melatonin onset 50% (2.94 vs. 2.70 h) and had increases in body temperature, serum melatonin levels, and cortisol levels, although these changes were not statistically significant. Use of blue light LED smartphones at night may negatively influence sleep and commission errors, while it may not be enough to lead to significant changes in serum melatonin and cortisol levels.

Comparisons of Subthreshold Versus Full Posttraumatic Stress Disorder Distinguished by Subjective Functional Impairment Among Train Drivers: A Population-Based Nationwide Study in South Korea

OBJECTIVE

Subthreshold posttraumatic stress disorder (SPTSD), a condition that meets the full symptomatic criteria of posttraumatic stress disorder (PTSD) without subjective functional impairment, has yet to be fully investigated. In this study, we aimed to determine the prevalence and characteristics of SPTSD.

METHODS

The web-based survey including psychiatric diagnosis and experience of human error was conducted in actively working train drivers in South Korea.

RESULTS

Of the 4,634 subjects, 103 (2.23%) were categorized as full PTSD and 322 (6.96%) were categorized as having SPTSD. Individuals with full PTSD showed higher impulsivity and anxiety compared to those with SPTSD and those without PTSD, while those with SPTSD had more frequent clinically meaningful depression, posttraumatic stress, and alcohol and nicotine dependence and significant human error.

CONCLUSION

Despite not qualifying as a subjective functional disability, SPTSD still had significant psychiatric symptoms. More clinical attentions need to be given to the diagnosis and treatment of SPTSD.