Shift Work Sleep Research Articles

Abstract 2181: Association of sleep duration, daytime napping, and night shift work with breast cancer risk

Abstract Sleep habit is closely related to melatonin which protect against breast cancer (BC). Sleep duration, nap habit, and shift work have been separately investigated to associate with BC risk, but the combination has not been reported. In this study, we collected all the sleep habits data from 712 women with incident invasive BC before their treatments and 742 age-matched female controls between July 2010 and January 2012 in Guangzhou, China. We found that the women with either shorter or longer sleep duration had increased BC risk compared to the women with normal sleep time of 6.1-8.9h/day [OR (95%CI: 1.62 (1.18-2.24) and 1.55 (1.14-2.10), respectively]. Night shift work also increased the risk of BC [1.36 (1.07-1.73)] and nap habits marginally associated a decreased risk [0.83 (0.66-1.04)]. Women with night shift work and longer sleep duration had an increased risk of BC [3.80 (1.99-7.26)] compared to the women with normal sleep time and no night shift work. The interaction on BC risk was significant (P for interaction=0.009). We conclude that abnormal sleep increases BC risk and longer sleep duration may not compensate the effect of night shift work on risk of BC. Table 1.Age-adjusted and multivariate-adjusted odds rations for the associations between sleep habits and breast cancer riskVariablesCases Controls OR#(95%CI)OR* (95%CI)OR^ (95%CI)(n=712) (%)(n=742)(%) Shift worknever443 (67.0)527 (73.8)1.00 (reference)1.00 (reference)1.00 (reference)ever218 (33.0)187 (26.2)1.39 (1.10-1.75)1.36 (1.07-1.73)1.34 (1.04-1.71)Napping statusnever293 (44.5)254 (37.7)1.00 (reference)1.00 (reference)1.00 (reference)ever365 (55.5)420 (62.3)0.75 (0.61-0.94)0.83 (0.66-1.04)0.83 (0.66-1.06)24-hour sleep duration≤6.0116 (17.7)85 (12.8)1.62 (1.18-2.21)1.62 (1.18-2.24)1.52 (1.10-2.11)6.1-8.9409 (62.6)485 (72.7)1.00 (reference)1.00 (reference)1.00 (reference)≥9.0129 (19.7)97 (14.5)1.58 (1.18-2.12)1.55 (1.14-2.10)1.59 (1.17-2.17)P-continuous0.6460.8830.451P-trend0.9090.9960.661OR#: Adjusted for age.OR*: Adjusted for age, education, BMI, marital status, age at menarche, menopausal status, parity, activity, breastfeeding and family history of breast cancer.OR^: Adjusted for age, education, BMI, marital status, age at menarche, menopausal status, parity, activity, breastfeeding, family history of breast cancer, and other sleep factors. Citation Format: Zefang Ren. Association of sleep duration, daytime napping, and night shift work with breast cancer risk. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2181. doi:10.1158/1538-7445.AM2014-2181

Narcolepsy and predictors of positive MSLTs in the Wisconsin Sleep Cohort.

To study whether positive multiple sleep latency tests (MSLTs, mean sleep latency [MSL] ≤ 8 minutes, ≥ 2 sleep onset REM sleep periods [SOREMPs]) and/or nocturnal SOREMP (REM sleep latency ≤ 15 minutes during nocturnal polysomonography [NPSG]) are stable traits and can reflect incipient narcolepsy. Cross-sectional and longitudinal investigation of the Wisconsin Sleep Cohort Study. Adults (44% females, 30-81 years) underwent NPSG (n = 4,866 in 1,518 subjects), and clinical MSLT (n = 1,135), with 823 having a repeat NPSG-MSLT at 4-year intervals, totaling 1725 NPSG with MSLT studies. Data were analyzed using linear mixed-effects models, and the stability of positive MSLTs was explored using κ statistics. Prevalence of a nocturnal SOREMP on a NPSG, of ≥ 2 SOREMPs on the MSLT, of MSL ≤ 8 minutes on the MSLT, and of a positive MSLT (MSL ≤ 8 minutes plus ≥ 2 SOREMPs) were 0.35%, 7.0%, 22%, and 3.4%, respectively. Correlates of a positive MSLT were shift work (OR = 7.8, P = 0.0001) and short sleep (OR = 1.51/h, P = 0.04). Test-retest for these parameters was poor, with κ < 0.2 (n.s.) after excluding shift workers and short sleepers. Excluding shift-work, short sleep, and subjects with negative MSLTs, we found one undiagnosed subject with possible cataplexy (≥ 1/month) and a NPSG SOREMPs; one subject previously diagnosed with narcolepsy without cataplexy with 2 NPSG SOREMPs and a positive MSLT, and two subjects with 2 independently positive MSLTs (66% human leukocyte antigen [HLA] positive). The proportions for narcolepsy with and without cataplexy were 0.07% (95% CI: 0.02-0.37%) and 0.20% (95% CI: 0.07-0.58%), respectively. The diagnostic value of multiple sleep latency tests is strongly altered by shift work and to a lesser extent by chronic sleep deprivation. The prevalence of narcolepsy without cataplexy may be 3-fold higher than that of narcolepsy-cataplexy.

Facteurs de pénibilité au travail chez les mécaniciens d’une entreprise de réparation navale d’Alger

Sleep deprivation due to shift work is related to perturbation of the sleep/wake cycle, associated with the modified activity/rest pattern. This may cause a significant disruption of circadian rhythms of biologic functions, driven by the body clock located in the suprachiasmatic nuclei of the hypothalamus.Shift and night workers have to change sleep times and strategies according to their duty periods; consequently, both sleep length and quality can be considerably affected depending on the variable start and finish times on different shifts.About 10% of night and rotating shift workers, aged between 18 and 65 years, have been estimated to have a diagnosable “shift-work sleep disorder,” according to the International Classification of Sleep Disorders, version 2 (ICSD-2).In the long run, this may lead to persistent and severe disturbances of sleep, chronic fatigue and psychoneurotic syndromes, besides being a risk or aggravating factor for accidents, gastrointestinal, cardiovascular, and reproductive disorders, as well as, probably, for cancer.Preventive and corrective actions deal with the organization of shift schedules according to ergonomic criteria, careful health surveillance, appropriate education and training on effective countermeasures, in particular, sleep hygiene and napping.

The influence of break timing on the sleep quantity and quality of fly-in, fly-out shiftworkers.

Although shift and break timing is known to affect the sleep of shiftworkers, this has not been demonstrated in Fly-in, Fly-out (FIFO) settings which, compared to residential based settings, may be favourable for sleep. This study investigated the sleep quantity and quality of shiftworkers working a FIFO operation comprising of shifts, and therefore breaks, across the 24-h day. The sleep of 24 males (50.43 ± 8.57 yr) was measured using actigraphy and sleep diaries. Morning breaks were associated with less sleep (09:00–12:00 h; 4.4 ± 1.3 h) and a poorer sleep quality (06:00–09:00 h; 3.1 ± 1.0, “average”) compared to breaks beginning between 00:00 h and 03:00 h (6.8 ± 1.7 h; 2.2 ± 0.9, “good”). Sleep efficiency remained constant regardless of break timing (85.9 ± 5.0% to 89.9 ± 3.5%). Results indicate that even in operations such as FIFO where sleeping conditions are near-optimal and the break duration is held constant, the influence of the endogenous circadian pacemaker on sleep duration is evident.

Shift Work Sleep Disorder and Complications

Shift work sleep disorder is actually a circadian rhythm disorder, the most common trouble faced by many individuals working in night shifts or rotational shifts, also refers as jet lag syndrome. This problem leads to disturbance in 24 hours body internal clock, as a result the internal clock needs to modify or reset the body sleep time. In this review we explain the complications and injuries faced in rotational shifts by shift work sleep disorders.

Selected Neurophysiological, Psychological, and Behavioral Influences on Subjective Sleep Quality in Nurses: A Structure Equation Model

Few studies have examined relationships among neurophysiological, psychological, and behavioral factors with regard to their effects on sleep quality. We used a structure equation model to investigate behavioral and psychological factors that influence neurophysiological regulation of sleep in shift workers. Using a cross-sectional study design, we tested the model with a sample of 338 female nurses working rotating shifts at an urban regional hospital. The Morningness-Eveningness Questionnaire (MEQ) and short-form Menstrual Distress Questionnaire (MDQ) were used to measure neurophysiological factors involved in morningness-eveningness and menstrual distress. The Sleep Hygiene Awareness and Practice Scale (SHAPS) and Profile of Mood States Short Form (POMS-SF) were completed to measure behavioral factors of sleep hygiene practices and psychological factors of mood states. In addition, the Pittsburgh Sleep Quality Index (PSQI) measured participant's self-reported sleep quality. The results revealed that sleep hygiene practices and mood states mediated the effects of morningness-eveningness and menstrual distress on sleep quality. Our findings provide support for developing interventions to enhance sleep hygiene and maintain positive mood states to reduce the influence of neurophysiological factors on sleep quality among shift workers.

Personality factors predict sleep-related shift work tolerance in different shifts at 2-year follow-up: a prospective study

ObjectivesThe aim of the present study was to investigate whether the personality variables morningness, flexibility, languidity and hardiness could predict sleep-related shift work tolerance for the day, evening and night...

The Vigilance Promoting Drug Modafinil Modulates Serotonin Transmission in the Rat Prefrontal Cortex and Dorsal Raphe Nucleus. Possible Relevance for Its Postulated Antidepressant Activity

Modafinil, (RS)-2-(diphenylmethylsulfinyl)acetamide derivative (Modiodal, Provigil), is a vigilance-promoting agent which reduces sleep episodes by improving wakefulness. It is approved by the USA FDA for narcolepsy, shiftwork sleep disorder and obstructive sleep apnoea with residual excessive sleepiness despite optimal use of continuous positive airway pressure. Unlike classical psychostimulants such as amphetamine and amphetamine-like compounds, the awaking effect of modafinil is not associated with a disturbance of nighttime sleep, tolerance, and sensitization. Its precise mechanism of action is still unclear. In animal studies, modafinil and its analogues have been shown to modify dopaminergic, noradrenergic, glutamatergic, GABAergic, serotoninergic, orexinergic, and histaminergic pathways. Besides the approved use in sleep disorders, modafinil has been investigated for the treatment of fatigue, impaired cognition and some symptoms in a number of other disorders. In particular, clinical studies seem to indicate that the drug could be particularly successful in the treatment of depression and its use in major depressive and bipolar disorders, has been suggested. However, the molecular mechanisms underlying this possible effect are still unknown. The present review firstly summarizes the structure-activity relationship studies and the mechanism of action of modafinil and its related compounds. Then, it focuses on data demonstrating that modafinil interacts with serotonin neuronal activity in rat frontal cortex and dorsal raphe nucleus, two brain areas linked together and involved in depression. Preclinical and clinical evidence of a positive interaction between modafinil and classical antidepressant drugs, is also summarized.

Shift-related sleep problems vary according to work schedule

ObjectivesShift-related sleep and sleepiness problems may be due to characteristics of both shifts (ie, day, evening and night shifts) and work schedules (ie, permanent vs rotational schedules). The Bergen Shift...

Modafinil and Armodafinil in Schizophrenia

What Might Be the Positive Spin-Offs Associated With Modafinil or Armodafinil Use in This Patient? Racemic modafinil and its R-isomer armodafinil are approved treatments for the excessive daytime drowsiness associated with narcolepsy, shift work, and obstructive sleep apnea1; therefore, either of these drugs could benefit Mr P. In schizophrenia, modafinil and armodafinil have been prescribed, studied, or suggested for off-label indications such as antipsychotic-induced drowsiness,2–4 antipsychotic-related weight gain,5,6 negative symptoms,3,4,7,8 and cognitive impairment.3,4,7,9,10 Favorable results for these off-label indications have mostly been described in anecdotal reports; with a few exceptions, the randomized controlled trials have generally found no advantage for these drugs over placebo. In summary, modafinil and armodafinil could be expected to improve daytime alertness in Mr P, but, realistically, cognitive and negative symptoms could improve only to the extent that they were worsened specifically by the daytime drowsiness.

Caring for the Country: Fatigue, Sleep and Mental Health in Australian Rural Paramedic Shiftworkers

This study investigated sleep quality, fatigue, mental health and physical activity in rural paramedic shiftworkers. Although limited, previous studies have associated high fatigue levels and poorer health in this sector with shiftwork rostering and occupational demands. A modified version of the Standard Shiftwork Index was completed by 150 paramedics (117 male and 31 females) from rural Victoria. Single sample t tests found significantly higher levels of fatigue, depression, anxiety, and stress, and significantly poorer sleep quality than reference samples. Paramedics also reported less physical activity than community samples. By regression analysis, sleep quality explained the greatest amount of variance in fatigue scores, followed by depression and age. No gender differences in levels of depression or fatigue were found. Consistent with an earlier study of metropolitan paramedics based on the same methodology, findings suggest rural ambulance paramedic shiftworkers are at particular risk for increased levels of fatigue and depression (regardless of age or gender) and poor quality sleep. Organisational intervention was suggested.

Circadian Phase, Sleepiness, and Light Exposure Assessment in Night Workers With and Without Shift Work Disorder

Most night workers are unable to adjust their circadian rhythms to the atypical hours of sleep and wake. Between 10% and 30% of shiftworkers report symptoms of excessive sleepiness and/or insomnia consistent with a diagnosis of shift work disorder (SWD). Difficulties in attaining appropriate shifts in circadian phase, in response to night work, may explain why some individuals develop SWD. In the present study, it was hypothesized that disturbances of sleep and wakefulness in shiftworkers are related to the degree of mismatch between their endogenous circadian rhythms and the night-work schedule of sleep during the day and wake activities at night. Five asymptomatic night workers (ANWs) (3 females; [mean ± SD] age: 39.2 ± 12.5 yrs; mean yrs on shift = 9.3) and five night workers meeting diagnostic criteria (International Classification of Sleep Disorders [ICSD]-2) for SWD (3 females; age: 35.6 ± 8.6 yrs; mean years on shift = 8.4) participated. All participants were admitted to the sleep center at 16:00 h, where they stayed in a dim light (<10 lux) private room for the study period of 25 consecutive hours. Saliva samples for melatonin assessment were collected at 30-min intervals. Circadian phase was determined from circadian rhythms of salivary melatonin onset (dim light melatonin onset, DLMO) calculated for each individual melatonin profile. Objective sleepiness was assessed using the multiple sleep latency test (MSLT; 13 trials, 2-h intervals starting at 17:00 h). A Mann-Whitney U test was used for evaluation of differences between groups. The DLMO in ANW group was 04:42 ± 3.25 h, whereas in the SWD group it was 20:42 ± 2.21 h (z = 2.4; p < .05). Sleep did not differ between groups, except the SWD group showed an earlier bedtime on off days from work relative to that in ANW group. The MSLT corresponding to night work time (01:00–09:00 h) was significantly shorter (3.6 ± .90 min: [M ± SEM]) in the SWD group compared with that in ANW group (6.8 ± .93 min). DLMO was significantly correlated with insomnia severity (r = −.68; p < .03), indicating that the workers with more severe insomnia symptoms had an earlier timing of DLMO. Finally, SWD subjects were exposed to more morning light (between 05:00 and 11:00 h) as than ANW ones (798 vs. 180 lux [M ± SD], respectively z = −1.7; p < .05). These data provide evidence of an internal physiological delay of the circadian pacemaker in asymptomatic night-shift workers. In contrast, individuals with SWD maintain a circadian phase position similar to day workers, leading to a mismatch/conflict between their endogenous rhythms and their sleep-wake schedule. (Author correspondence: vgumeny1@hfhs.org)

A Reliability and Validity Study of the Bergen Shift Work Sleep Questionnaire in Nurses Working Three-Shift Rotations

The “Bergen Shift Work Sleep Questionnaire” (BSWSQ) was developed to systematically assess discrete sleep problems related to different work shifts (day, evening, night shifts) and rest days. In this study, we assessed the psychometric properties of the BSWSQ using a sample of 760 nurses, all working in a three-shift rotation schedule: day, evening, and night shifts. BSWSQ measures insomnia symptoms using seven questions: >30-min sleep onset latency, >30-min wake after sleep onset, >30-min premature awakenings, nonrestorative sleep, being tired/sleepy at work, during free time on work days, and when not working/on vacation. Symptoms are assessed separately for each work shift and rest days, as “never,” “rarely,” “sometimes,” “often,” “always,” or “not applicable.” We investigated the BSWSQ model fit, reliability (test-retest of a subsample, n = 234), and convergent and discriminant validity between the BSWSQ and Epworth Sleepiness Scale, Fatigue Questionnaire, and Hospital Anxiety Depression Scale. We also investigated differences in mean scores between the different insomnia symptoms with respect to different work shifts and rest days. BSWSQ demonstrated an adequate model fit using structural equation modeling: root mean square error of approximation = .071 (90% confidence interval [CI] = .066–.076), comparative fit index = .91, and chi-square/degrees of freedom = 4.41. The BSWSQ demonstrated good reliability (test-retest coefficients p < .001). We found good convergent and discriminant validity between BSWSQ and the other scales (all coefficients p < .001). There were significant differences between the overall/composite scores of the various work shifts. Night shift showed the highest score compared to day and evening shifts as well as to rest days (all post hoc comparisons p < .001). Mean scores of different symptoms also varied significantly within the individual work shifts. We conclude that the BSWSQ meets the necessary psychometric standards, enabling systematic study of discrete insomnia symptoms in different work shifts. (Author correspondence: elisabeth.flo@psykp.uib.no)

Melatonergic Drugs in Clinical Practice

Melatonin (CAS 73-31-4) has both hypnotic and sleep/wake rhythm regulating properties. These sleep promoting actions, which are already demonstrable in healthy humans, have been found useful in subjects suffering from circadian rhythm sleep disorders (CRSD) like delayed sleep phase syndrome (DSPS), jet lag and shift-work sleep disorder. Low nocturnal melatonin production and secretion have been documented in elderly insomniacs, and exogenous melatonin has been shown to be beneficial in treating sleep disturbances of these patients. In comparison to a number of sleep-promoting compounds that are usually prescribed, such as benzodiazepines and z-drugs (zolpidem and zopiclon belonging to the latter ones), melatonin has several advantages of clinical value: it does not cause hangover nor withdrawal effects and is devoid of any addictive potential. However, recent meta-analyses revealed that melatonin is not sufficiently effective in treating most primary sleep disorders. Some of the reasons for a limited efficacy of this natural hormone are related to its extremely short half-life in the circulation, and to the fact that sleep maintenance is also regulated by mechanisms downstream of primary melatonergic actions. Hence, there is an urgent need for the development of melatonin receptor agonists with a longer half-life, which could be suitable for a successful treatment of insomnia. Such requirements are fulfilled by ramelteon (CAS 196597-26-9), which possesses a high affinity for the melatonin receptors MT1 and MT2 present in the circadian pacemaker, the suprachiasmatic nucleus (SCN). Ramelteon also has a substantially longer half-life than melatonin. This new drug has been successfully used in treating elderly insomniacs without any adverse effects reported, and is promising for treating patients with primary insomnia and also those suffering from CRSD. Since sleep disturbances constitute the most prevalent symptoms of various forms of depression, the need for the development of an ideal antidepressant was felt, which would both improve sleep and mitigate depressive symptoms. Since most of the currently used antidepressants, including the selective serotonin re-uptake inhibitors worsen the sleep disturbances of depressive patients, another novel melatonergic drug, agomelatine (CAS 138112-76-2), holds some promise because of its particular combination of actions: it has a high affinity for MT1 and MT2 receptors in the SCN, but it acts additionally as a 5-HT(2C) antagonist [5-hydroxytryptamine (serotonin) receptor 2C antagonist]. The latter property, which is decisive for the antidepressive action, would not favor but potentially antagonize sleep, but this is overcome during night by the melatonergic, sleep-promoting effect. This drug has been found beneficial in treating patients with major depressive and seasonal affective disorders. Unlike the other antidepressants, agomelatine improves both sleep and clinical symptoms of depressive illness and does not have any of the side effects on sleep seen with other compounds in use. This property seems to be of particular value because of the aggravating effects of disturbed sleep in the development of depressive symptoms. Based on these facts, agomelatine seems to be a drug of superior efficacy with a promising future in the treatment of depressive disorders. However, long-term safety studies are required for both ramelteon and agomelatine, with a consideration of the pharmacology of their metabolites, their effects on redox metabolism, and of eventual undesired melatonergic effects, e. g., on reproductive functions. According to current data, both compounds seem to be safe during short-term treatment

Sleep and psychomotor vigilance in female shiftworkers.

The purpose of this study was to evaluate the relationships between sleep and psychomotor vigilance in female nurses and the changes in these variables over time. Participants comprised 16 staff registered nurses (10 day, 6 night; aged 30-65 years [M = 47.6; SD = 8.1]) who wore wrist actigraphs continuously and completed a 10-min psychomotor vigilance test (PVT-192, Ambulatory Monitoring, Inc., Ardsley, New York) and the Stanford Sleepiness Scale (SSS) in their homes before and after work for three consecutive 24-hr periods. Repeated measures ANOVA revealed that night nurses slept significantly less than day nurses, F(1, 15) = 26.06, p ≤ .001; M = 227.88 ± 37.03 min versus M = 365.75 ± 59.01 min, respectively, daily for three consecutive days. Night nurses napped more frequently and had more changes in the length of their main sleep periods than day nurses. Day nurses reported more wake episodes during main sleep periods. Night nurses were sleepier after work than day nurses; both groups had increased sleepiness after work for the first 2 days and similar psychomotor vigilance test results. These findings suggest that sleep deprivation, irregular sleep patterns, and sleepiness are significant issues for shiftworking nurses. Future study of the characteristics of sleep and sleepiness in a larger sample would be useful to evaluate the focus for interventions to improve sleep and alertness in shiftworking nurses.

Armodafinil versus Modafinil in Patients of Excessive Sleepiness Associated with Shift Work Sleep Disorder: A Randomized Double Blind Multicentric Clinical Trial

Aim. To compare the efficacy and safety of armodafinil, the R-enantiomer of modafinil, with modafinil in patients of shift work sleep disorder (SWSD). Material and Methods. This was a 12-week, randomized, comparative, double-blind, multicentric, parallel-group study in 211 patients of SWSD, receiving armodafinil (150 mg) or modafinil (200 mg) one hour prior to the night shift. Outcome Measures. Efficacy was assessed by change in stanford sleepiness score (SSS) by at least 2 grades (responder) and global assessment for efficacy. Safety was assessed by incidence of adverse events, change in laboratory parameters, ECG, and global assessment of tolerability. Results. Both modafinil and armodafinil significantly improved sleepiness mean grades as compared to baseline (P < .0001). Responder rates with armodafinil (72.12%) and modafinil (74.29%) were comparable (P = .76). Adverse event incidences were comparable. Conclusion. Armodafinil was found to be safe and effective in the treatment of SWSD in Indian patients. The study did not demonstrate any difference in efficacy and safety of armodafinil 150 mg and modafinil 200 mg.

Do Evoked Potential Differences Reflect a Deficit in Those Suffering a Sleep Disorder, or Resilience in Those Who Can Avoid it?

Do Evoked Potential Differences Reflect a Deficit in Those Suffering a Sleep Disorder, or Resilience in Those Who Can Avoid it?

Shift Work Sleep Disorder is Associated with an Attenuated Brain Response of Sensory Memory and an Increased Brain Response to Novelty: An ERP study

To study the neurophysiological changes in attention and memory functions in shift work sleep disorder (SWSD), using event-related brain potentials (ERPs). 9 healthy night workers (NW) (mean age = 40 y; SD +/- 8.9 y); 8 night workers meeting diagnostic criteria for SWSD (mean age = 37 y +/- 9.4 y) and 9 healthy day workers (DW) (mean age = 35 y +/- 7.3 y). Using standard PSG the sleep related measures (TIB, TST, SOL, SE, and sleep stage distribution) were obtained prior to EEG/ERP study. Measures of habitual sleep were obtained from 2 week sleep logs and sleepiness was assessed with standardized measures. Using 32-EEG leads the ERPs to 3 types of sounds (novel, duration deviant, and simple tone) were obtained. The mismatch negativity (MMN) reflecting memory processing and P3a-reflecting the shift of involuntary attention were obtained. The statistical comparisons of ERPs and sleep related parameters were performed using repeated measured ANOVAs and t-tests where appropriate. Patients with SWSD had reduced TST and increased WASO relative to healthy workers. ERP results demonstrated significant attenuation of MMN amplitude over frontal regions in SWSD patients relative to NW and DW. In the SWSD patients, the P3a was increased to novelty across frontocentral brain regions with respect to the same locations in healthy controls. The ERP evidence of sensory memory reduction and attentional hyper-reaction to novel sound in conjunction with disturbed sleep suggests the need for more neurophysiological studies in SWSD workers.

Caring for the Carers: Fatigue, Sleep, and Mental Health in Australian Paramedic Shiftworkers

AbstractThis study investigated fatigue, sleep quality, mental health and physical activity in paramedic shiftworkers. Although limited, previous studies have established high fatigue levels and poor health in this sector from shiftwork rostering and occupational demands. A modified version of the Standard Shiftwork Index was completed by 342 paramedics (243 male and 98 females). Single sample t tests found significantly higher levels of fatigue, depression, anxiety, and stress, and significantly poorer sleep quality than reference samples. Paramedics also reported less physical activity than community samples. Depression and sleep quality explained the greatest amount of variance in fatigue scores, followed by level of exercise. No differences were detected in levels of depression or fatigue on the basis of gender. The findings suggest that ambulance paramedic shiftworkers are at particular risk for increased levels of fatigue and depression (regardless of age or gender) and poor quality sleep. Organisational intervention was suggested.

Pathological Gambling Associated With Modafinil

Back to table of contents Previous article Next article LETTERFull AccessPathological Gambling Associated With ModafinilN. Tarrant,A. E. Cavanna,H. Rickards,N. TarrantSearch for more papers by this author,A. E. CavannaSearch for more papers by this author,H. RickardsSearch for more papers by this author,Published Online:1 Jan 2010https://doi.org/10.1176/jnp.2010.22.1.123.e27AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail To the Editor: Pathological gambling is defined by the DSM-IV-TR as a clinical condition characterized by persistent and maladaptive gambling behaviors; these are severe enough to disrupt the patient’s life and relationships and are not due to a manic episode. 1 Based on gambling behavior phenomenology, comorbid psychiatric conditions, family history, and demographics, it has been proposed that pathological gambling can present in three clinical subtypes: impulsive, obsessive-compulsive, and addictive. 2 Pathological gambling has been reported in association with dopamine agonists used in Parkinson’s disease, 3 restless legs syndrome, and endocrine disorders. The European Union Pharmacovigilance Working Party recommends that summaries of product characteristics for dopamine agonists carry a warning about pathological gambling as a side effect. To the best of our knowledge, there are currently no published reports of pathological gambling associated with modafinil, and there have been no Yellow Card reports submitted to the U.K. Commission on Human Medicines.Case ReportMr. C was referred to the neuropsychiatry clinic at the age of 39 with a 12-year history of narcolepsy (HLA-DBQ1*0602 positive) and associated cataplexy. He had no significant medical or psychiatric history and was being treated with modafinil, 300 mg daily in two divided doses. Initially there was a good response, but a developing tolerance prompted the referral. The patient had a prior history of minor gambling but reported a 10-fold increase in his slot-machine use, spending £20,000–£30,000 a year, since commencing modafinil. The patient was hesitant to increase the dose in case his gambling habit worsened.It was decided to withhold modafinil for a 2-month trial. At the next review, the patient complained of increased somnolence without the medication but reported that his gambling habit had considerably decreased. His somnolence had necessitated restarting modafinil, and his gambling had increased once again. He was started on clomipramine, 50 mg at night, with a view to titrating up to 150 mg/day to alleviate his compulsive behavior.Eighteen months later, he was taking clomipramine, 40 mg at night, and had discontinued modafinil. He reported that he was no longer gambling.DiscussionModafinil is currently licensed in the United Kingdom for the symptomatic relief of excessive sleepiness associated with narcolepsy, obstructive sleep apnea, and moderate to severe chronic shift-work sleep disorder. Its use is also under study for cocaine dependence and attention-deficit/hyperactivity disorder. In this patient, we observed a clear-cut temporal relationship between modafinil treatment and a gambling habit, with an improvement after withdrawal and worsening on rechallenge. The precise mechanism of action of modafinil is still unclear. 4 Modafinil is thought to increase wakefulness by blocking dopamine clearance through inhibition of the dopamine transporter and has been shown to increase cortical and caudate dopamine concentrations. 5 The effects of modafinil on impulsive/compulsive symptoms have been poorly investigated. A recent controlled study suggested that modafinil can have bidirectional effects on pathological gambling patients. Specifically, it has been shown to increase desire to gamble, disinhibition, and risky decision-making in low impulsivity subjects, while decreasing these indexes in high impulsivity subjects. 6 Overall, reward-seeking behavior, especially pathological gambling-compulsive/addictive subtype, may represent a possible adverse effect of modafinil via potentiation of the dopaminergic system in predisposed individuals. University of Birmingham Medical School, Birmingham, UKDepartment of Neuropsychiatry, Birmingham and Solihull Mental Health NHS Foundation Trust, Birmingham, UK Department of Neuropsychiatry, Institute of Neurology, London, UKDepartment of Neuropsychiatry, Birmingham and Solihull Mental Health NHS Foundation Trust, Birmingham, UK