Biological Rhythm Disturbances Research Articles

Clinical features of differential diagnosis between unipolar and bipolar depression in a drug-free sample of young adults

IntroductionSubjects with bipolar disorder suffering of a depressive episode are frequently misdiagnosed as unipolar depression, being important studies assessing the differential diagnosis between bipolar and unipolar depression. ObjectiveTo assess the sociodemographic and clinical features of drug-free young adults in a depressive episode of bipolar or unipolar disorder in order to identify factors that may differentiate these psychiatric conditions. MethodsThis is a cross-sectional study with 241 young adults aged between 18 and 29 years who were evaluated using the Structured Clinical Interview for DSM-IV (SCID). The sample comprised patients with BD (n = 89) and major depressive disorder (n = 152), experiencing a depressive episode and not using psychoactive drugs or illicit psychoactive substances. ResultsThe characteristics associated with bipolar depression were being male (p < 0.001), with a family history of BD (p = 0.013), a higher frequency of childhood traumatic experiences (p = 0.001), younger age of onset of mood disorder (p = 0.004), many previous depressive episodes (p = 0.027), greater severity of depressive symptoms (p < 0.001) and day/night reversal (p = 0.013). Those with unipolar depression showed a higher frequency of biological rhythm disturbances (p < 0.001), and diurnal preference (p = 0.028). LimitationsThe sample has not included subjects with severe suicide risk, a possible important marker in differentiate unipolar from bipolar depression. ConclusionSome clinical aspects may contribute to an early differential diagnosis of both bipolar and unipolar depression even in the initial stages of the disease.

Biological Rhythms, Sleep Quality and Postpartum Depression Disorder

Postpartum Depression Disorder (PDD) is one of the most recent major depressive episodes, many of which begin with symptoms during pregnancy and become more intense after childbirth. The aim of this study was to investigate the role of biological rhythms and sleep quality in the prediction of PDD. The research method was descriptive-correlational. The statistical population of this study included all women with PDD who referred to health centers of Talesh city (Iran) in the second half of 2016. A total of 110 women were selected through purposive sampling and responded to the Biological rhythms interview, Pittsburgh's Sleep Quality Questionnaires and Beck's Depression Inventory. Data was analyzed using Pearson correlation coefficient and multiple regression analysis. The results showed that postpartum depression has a positive correlation with the disturbance of biological rhythms and sleep problems. The results of regression analysis also showed that biological rhythms and sleep quality predict 44% and 43% of postpartum depression in women under study. These results indicate that disturbance in biological rhythms and sleep, arose at postpartum period, may be a major risk factor for postpartum depression.

Biological dysrhythm in remitted bipolar I disorder.

Recent treatment guidelines support treatment of biological rhythm abnormalities as a part of treatment of bipolar disorder, but still, literature examining various domains (Sleep, Activity, Social, and Eating) of biological rhythm and its clinical predictors are less. The main aim of our study is to compare various domains of biological rhythm among remitted bipolar I subjects and healthy controls. We also explored for any association between clinical variables and biological rhythm among bipolar subjects. 40 subjects with Bipolar I disorder and 40 healthy controls who met inclusion and exclusion criteria were recruited for the study. Diagnoses were ascertained by a qualified psychiatrist using MINI 5.0. Sociodemographic details, biological rhythm (BRIAN-Biological Rhythm Interview of assessment in Neuropsychiatry) and Sleep functioning (PSQI- Pittsburgh Sleep Quality Index) were assessed in all subjects. Mean age of the Bipolar subjects and controls were 41.25±11.84years and 38.25±11.25 years respectively. Bipolar subjects experienced more biological rhythm disturbance when compared to healthy controls (total BRIAN score being 34.25±9.36 vs 28.2±6.53) (p=0.002). Subsyndromal depressive symptoms (HDRS) had significant positive correlation with BRIAN global scores(r=0.368, p=0.02). Linear regression analysis showed that number of episodes which required hospitalization (β=0.601, t=3.106, P=0.004), PSQI (β=0.394, t=2.609, p=0.014), HDRS (β=0.376, t=2.34, t=0.036) explained 31% of variance in BRIAN scores in remitted bipolar subjects. Biological rhythm disturbances seem to persist even after clinical remission of bipolar illness. More studies to look into the impact of subsyndromal depressive symptoms on biological rhythm are needed.

A Study of Biological Rhythm Disturbances in Polish Remitted Bipolar Patients using the BRIAN, CSM, and SWPAQ Scales

Background/Aims: The Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) is a novel tool allowing for a complex assessment of biological rhythms. We compared patients with bipolar disorder (BD) and healthy control subjects (HC) using the Polish version of the BRIAN scale. Method: Fifty-four remitted BD patients (17 males and 37 females aged 52 ± 13 years) and 54 healthy control subjects (25 males and 29 females aged 42 ± 14 years) were studied. In addition to the BRIAN scale, the Composite Scale of Morningness (CSM) and the Sleep-Wake Pattern Assessment Questionnaire (SWPAQ) were employed. Results: The Polish version of the BRIAN scale displayed high feasibility and consistency, showing that the patients had greater biological rhythm disturbances than the controls. After regression analysis, significant differences were obtained for the BRIAN subscales activity and predominant chronotype, and for the SWPAQ items quality of night-time sleep and ability to stay awake. We obtained positive correlations between higher BRIAN scores and morningness and eveningness, but the correlations with vigilance and the ability to stay awake (on the SWPAQ) were negative. Conclusions: Using the BRIAN scale, we confirmed the greater disturbances of biological rhythm in Polish remitted bipolar patients, compared with healthy controls. The differences between these 2 groups in sleep-awake patterns were also demonstrated by the SWPAQ scores. In contrast to other studies, we were unable to confirm an evening chronotype as a discriminating factor between remitted bipolar patients and healthy subjects. This can be explained by the older age and the use of lithium by a significant proportion of the patients.

The Biological Rhythms Interview of Assessment in Neuropsychiatry in patients with bipolar disorder: correlation with affective temperaments and schizotypy.

Objective:To assess the relationship of biological rhythms, evaluated by the Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN), with affective temperaments and schizotypy.Methods:The BRIAN assessment, along with the Temperament Evaluation of Memphis, Pisa, Paris, and San Diego-Autoquestionnaire (TEMPS-A) and the Oxford-Liverpool Inventory for Feelings and Experiences (O-LIFE), was administered to 54 patients with remitted bipolar disorder (BD) and 54 healthy control (HC) subjects.Results:The TEMPS-A cyclothymic temperament correlated positively and the hyperthymic temperament correlated negatively with BRIAN scores in both the BD and HC groups, although the correlation was stronger in BD subjects. Depressive temperament was associated with BRIAN scores in BD but not in HC; conversely, the irritable temperament was associated with BRIAN scores in HC, but not in BD. Several positive correlations between BRIAN scores and the schizotypal dimensions of the O-LIFE were observed in both BD and HC subjects, especially with cognitive disorganization and less so with unusual experiences and impulsive nonconformity. A correlation with introversion/anhedonia was found only in BD subjects.Conclusion:Cyclothymic and depressive temperaments predispose to disturbances of biological rhythms in BD, while a hyperthymic temperament can be protective. Similar predispositions were also found for all schizotypal dimensions, mostly for cognitive disorganization.

Biological rhythms are independently associated with quality of life in bipolar disorder.

BackgroundEvidence suggests that patients with bipolar disorder (BD) experience biological rhythm disturbances; however, no studies have examined the impact of this disruption on quality of life (QOL). The aim of this study is to investigate the influence of biological rhythm, depressive symptoms, sleep quality, and sleep medication use on QOL in BD.MethodsEighty BD subjects (44 depressed and 36 euthymic) completed questionnaires assessing QOL (WHOQOL-BREF), biological rhythm disruption (BRIAN), depressive symptoms (MADRS), and sleep quality (PSQI). The impact of biological rhythm disturbance, depressive symptoms severity, sleep quality, and sleep medication use on QOL was determined with multiple regression analyses.ResultsBRIAN (β = −0.31, t = −2.73, p < 0.01), MADRS (β = −0.30, t = −2.93, p < 0.01), and sleep medication use (β = −0.45, t = −2.55, p < 0.05) were significant predictors of QOL in this model (F4, 75 = 20.28; p < 0.0001). The relationship of these factors with subdomains of QOL showed that poorer social QOL was associated with greater biological rhythm disturbance (β = −0.43, t = −3.66, p < 0.01) and sleep medication use (β = −0.49, t = −2.35, p < 0.01), providing support for the social rhythm theory of BD. Physical QOL was associated with depression (β = −0.30, t = −2.93, p < 0.01) and biological rhythm disruption (β = −0.31, t = −2.73, p < 0.01). Main limitations include the cross-sectional assessment and the lack of objective measures of biological rhythms in relation to QOL.ConclusionsDisruption in biological rhythm is associated with poor QOL in BD, independent of sleep disturbance, sleep medication use, and severity of depression. Treatment strategies targeting regulation of biological rhythms, such as sleep/wake cycles, eating patterns, activities, and social rhythms, are likely to improve QOL in this population.

Do changes in subjective sleep and biological rhythms predict worsening in postpartum depressive symptoms? A prospective study across the perinatal period.

Abnormalities of sleep and biological rhythms have been widely implicated in the pathophysiology of major depressive disorder (MDD) and bipolar disorder (BD). However, less is known about the influence of biological rhythm disruptions across the perinatal period on postpartum depression (PPD). The objective of this study was to prospectively evaluate the relationship between subjective changes in both sleep and biological rhythms and worsening of depressive symptoms from pregnancy to the postpartum period in women with and without mood disorders. Eighty-three participants (38 euthymic women with a history of a mood disorder and 45 healthy controls) werestudied. Participants completed subjective assessments of sleep (Pittsburgh Sleep Quality Index), biological rhythm disturbances (Biological Rhythms Interview of Assessment in Neuropsychiatry), and depressive symptoms (Edinburgh Postnatal Depression Scale) prospectively at two time points: third trimester of pregnancy and at 6-12weeks postpartum. Multivariate regression analyses showed that changes in biological rhythms across the perinatal period predicted worsening of depressive symptoms in both groups. Moreover, women with a history of a mood disorder showed higher levels of sleep and biological rhythm disruption during both pregnancy and the postpartum period. These findings suggest that disruptions in biological rhythms during the perinatal period increase the risk for postpartum mood worsening in healthy pregnant as well as in pregnant women with a history of mood disorders.

Biological rhythm disturbances in patients with bipolar disorder under remission

Biological rhythm disturbances in patients with bipolar disorder under remission

English

This study evaluated biological rhythm disorders in patients with fibromyalgia syndrome (FMS). The study enrolled 82 patients with FMS and 82 controls. Pain intensity was evaluated using a visual analogue scale (VAS). The psychological conditions of the patients were evaluated using the Beck Depression Inventory (BDI). The Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) was used to assess disturbances in biological rhythms (ie sleep, activity, social and eating patterns). There was no difference between the two groups at baseline (all p > 0.05). The BDI, BRIAN total, sleep, activity, social, and eating scores were higher in patients with FMS than in the controls (all p < 0.001). Further, a significant correlation was found between biological rhythms and BDI scores (p < 0.001) and there were positive correlations between the VAS score and BRIAN total, sleep, and eating and BDI in patients with FMS (all p < 0.001). There are marked biological rhythm disturbances in FMS. There is an important relationship between rhythm disorders and FMS. The disturbances in sleep, functional activities, social participation, and disordered rhythms like eating patterns show the need for a multidisciplinary approach to treating patients with FMS.

Effects of biological rhythm disturbance on sedation induced by propofol in rats

Objective To evaluate the effects of biological rhythm disturbance on sedation induced by propofol in rats. Methods Thirty-two adult male Sprague-Dawley rats, weighing 180-220 g, were randomly divided into 4 groups(n=8 each)using a random number table: circadian rhythm+ administration during night-time group(group CN), circadian rhythm+ administration during day-time group(group CD), biological rhythm+ administration during night-time group(group BN), and biological rhythm+ administration during day-time group(group BD). In CN and CD groups, the rats were fed for 2 weeks in the experimental boxes in a 12(7: 00–19: 00): 12 h(19: 00–7: 00)light: dark cycle.While the rats were fed for 2 weeks in the experimental boxes in a 24 h light cycle.Propofol 75 mg/kg was intraperitoneally injected at 14: 00 in CN and BN groups, or at 22: 00 in CD and BD groups.The duration of loss of righting reflex was recorded.At 20 min after recovery of righting reflex, the cognitive function was assessed.The latency of passive avoidance was measured at 6, 12, 24 and 48 h after training. Results Compared with group CN, the duration of loss of righting reflex was significantly shortened, and the latency of passive avoidance was prolonged at 12 and 24 h after training in group CD, and the duration of loss of righting reflex and latency of passive avoidance at 12 and 24 h after training were shortened in group BN.Compared with group CD, no significant change was found in the duration of loss of righting reflex, and the latency of passive avoidance was significantly shortened at 24 h after training in group BD.There was no significant change between BN group and BD group in the duration of loss of righting reflex and latency of passive avoidance. Conclusion Biological rhythm disturbance can counteract circadian rhythm-produced effects on sedation induced by propofol in rats. Key words: Biorhythms; Propofol; Conscious sedation

PSYCHOLOGICAL ADAPTATION FEATURES IN PEDIATRICIANS

Objective: to detect asthenia, weariness and sleep disorders in pediatricians. Material and methods. Cross-sectional study of 44 pediatricians with the use of a package of psychometric tools (scale for assessing weariness SB-2003, Pittsburgh Insomnia Rating Scale (PIRS), subjective rating scale of asthenia MFI-20). Results. 42 (95 %) of the respondents from the study group revealed moderate or severe emotional weariness. Only 5 (11 %) of the respondents did not reveal any signs of asthenic symptomatic complex. All the respondents in the survey had this or that form of a sleep disorder. Conclusion. The job of a pediatrician involves high-level professional emotional stress, which affects the quality of life, determines the psychological status and, later, somatic well-being, indirectly influencing the satisfaction of consumers of medical services. Asthenic symptoms, sleep disorders and emotional weariness, which are common among doctors of this specialty, may be indicative of circadian rhythm disorders associated with professional desynchronosis. The use of tranquillizers and sleeping pills, consumption of alcohol or other psychoactive substances in order to correct sleep disorders show a decrease or a failure in the adaptation potential of pediatricians under the impact of extreme loads and professionally deterministic disturbances of biological rhythms, inefficient psychological protection.

Disruption of running activity rhythm following restricted feeding in female mice: Preventive effects of antidepressants

Biological rhythms are critical in the etiology of mood disorders; therefore, effective mood disorder treatments should address rhythm disturbances. Among the variables synchronized with the light–dark cycle, spontaneous activity in rodents is useful for investigating circadian rhythms. However, previous studies have focused only on the increase of wheel-running activity under restricted feeding conditions, while little information is available on circadian rhythm of running activity. In this study, chronometrical analysis was used to assess whether circadian rhythms during wheel-running are altered by restricted feeding and affected by antidepressant drugs. Wheel revolutions were automatically recorded and analyzed using cosinor-rhythmometry in 8-week old ICR albino mice. When feeding was restricted to 1 h per day (21:00–22:00), wheel-running rhythms were reliably disrupted. Female mice exhibited marked alterations in the pattern and extent of wheel-running beginning on day 1. Subchronic treatment with imipramine or paroxetine, as well as tandospirone and (−)-DOI, prevented wheel-running rhythm disruption. Thus, altering the circadian activity rhythms of female mice on a 1-h feeding schedule may be useful for investigating disturbances in biological rhythms.

Fasting during Ramadan is associated with a higher recurrence rate in patients with bipolar disorder

Fasting during the Ramadan month is a cornerstone of Islam. Several disturbances of biological rhythms have been reported in fasters during that month 1, but there is no consensus on the impact of fasting on patients with bipolar disorder 2,3. We conducted a study in 170 patients with stabilized bipolar disorder (DSM-IV criteria), including 111 fasters and 59 non-fasters, targeting the Ramadan month of two successive years (2011 and 2012). Participants were recruited among outpatients at the Casablanca Ibn Rushd University Psychiatric Center. They were assessed for depression by the Hamilton Depression Rating Scale, for mania by the Bech-Rafaelsen Scale, for anxiety by the Hamilton Anxiety Rating Scale, for stress by the Perceived Stress Scale 4, for religiosity by the Religious Practices Index 5. Sleep and eating patterns, use of stimulants and other drugs, and plasma lithium levels were also assessed. The evaluations were conducted one week before the month of Ramadan (W−1), on the second and fourth week of Ramadan (W2 and W4), and two weeks after the end of the Ramadan month (W+2). The mean age of patients was 36.2±12.0 years; 51.2% were women; 62.4% were single; 51.8% were professionally active. The number of mood episodes per year was 0.72± 0.45. All patients were under mood stabilizers; 81.2% were also receiving antipsychotics; 21 patients were also receiving antidepressants. The relapse rate among fasters was 33.3% (37/111), including 14 relapses at W2 (7 manic and 7 depressive), 9 more at W4 (6 manic and 3 depressive) and 14 more at W+2 (13 manic and one depressive). The relapse rate among non-fasters was 15.3% (9/59), including 3 manic relapses at W2, 4 more relapses at W4 (1 manic and 3 depressive) and two more at W+2 (one manic and one depressive). The difference between fasters and non-fasters was statistically significant (χ2=6.38, p=0.012). Fasting during the Ramadan month increased the risk of relapse among bipolar patients by 2.77 fold in comparison to non-fasters (95% CI: 1.233 to 6.254, p=0.014). The number of sleeping hours decreased more significantly during the month of Ramadan among fasters (from 9.39±1.45 at W−1 to 7.34±1.64 at W4) as compared to non-fasters (from 9.92±1.28 at W−1 to 8.59±2.17 at W4) (p<0.0001). Coffee consumption during the month increased in fasters (from 1.47±1.51 cups at W−1 to 1.94±1.94 at W4) more than in non-fasters (from 1.61±1.59 cups at W−1 to 1.76±1.75 at W4), but the difference was not statistically significant. Serum lithium levels did not differ significantly between fasters (mean: 0.57±0.65 mEq/l at W−1 and 0.65± 0.71 mEq/l at W4) and non-fasters (mean: 0.57±0.11 mEq/l at W−1 and 0.64±0.75 mEq/l at W4). After controlling for the number of sleeping hours, coffee consumption and serum lithium levels, the recurrence rate remained higher in fasters than in non-fasters. This study suggests that fasting during the month of Ramadan may have a negative impact on patients with bipolar disorder. This could lead to preventive measures against relapses for persons with bipolar disorders in Muslim countries (more than 1 billion people worldwide). Studies on larger samples are needed to replicate these findings.

Is the biological clock central to the aging process? Studies in a non-human primate

The ability of organisms to adapt to their environment during aging is altered. Age-related disorders in Human include disturbances of biological rhythms, especially sleep-wake rhythms alterations, and perturbations of body temperature and hormone secretion. The alteration of biological rhythms with age leads to major health consequences, particularly due to the alteration of sleep-wake rhythms that causes a strong alteration of the general condition. The study of these changes is therefore a major health issue and requires the use of appropriate animal models such as the grey mouse lemur (Microcebus murinus), a small Madagascar primate with very pronounced biological rhythms.

Факторы риска возникновения психических нарушений в отдаленном периоде черепно-мозговой травмы

У 437 больных, которые перенесли черепно-мозговую травму (ЧМТ) и имеют определенную психопатологию, с помощью клинических обследований, психометрических шкал, лабораторных методов, включавших проточную цитометрию и определение уровня мелатонина, а также инструментальных методов (КТ, МРТ, ЭЭГ, РЭГ) выявлены факторы риска неблагоприятного прогноза в отдаленном периоде черепно-мозговой травмы, что приводит к тяжелым психическим расстройствам. Установлено, что важнейшими из них могут считаться следующие: выраженная астения, нарушение регуляции апоптоза, биологических ритмов, а именно — извращение температурной кривой, обмена мелатонина, инсомнии. Характерно, что вышеуказанные нарушения достигали большой выраженности даже у лиц, перенесших легкую ЧМТ. При этом наиболее распространенными неблагоприятными последствиями ЧМТ были такие психопатологические проявления, как когнитивные, шизофреноподобные и аффективные расстройства. Функциональные расстройства, возникшие у лиц, перенесших легкую ЧМТ, с течением времени приводили к стойкому нарушению адаптационной системы всего организма.

Circadian rhythm of wrist temperature and night shift-work

The stability of the circadian rhythms, especially regarding their amplitude and phase relationship, is a major factor for health. Shift-work and working night shifts are known to be associated with a variety of health problems caused, at least partially, by the disturbance of biological rhythms. Seventeen undergraduate nursing students attending the morning program at Nursing School, and working night shifts as Nursing Technicians, were submitted to the morningness–eveningness questionnaire, sleep logs, and wrist temperature assessment, during two periods of 2 weeks (school term and vacation). The observed prominent ultradian periods and reduced amplitude of the daily rhythm of wrist temperature, in addition to the reduced sleep duration during the school term, reinforce the idea that the mixed routine contributes to the disruption of the expression of the circadian rhythms and may have detrimental effects on safety and performance at work.

Biological rhythm disturbance in remitted bipolar patients.

BackgroundBiological rhythm disturbance is common in bipolar patients and seems to affect the course and prognosis of the illness negatively. The main aim of the current study was to assess biological rhythms in remitted bipolar patients. We also assessed whether there was an association between clinical variables or functioning and biological rhythms in remitted bipolar participants.MethodsThe Biological Rhythms Interview of Assessment in Neuropsychiatry (BRIAN) was used to assess biological rhythm disturbance. It is an 18-item interviewer-administered instrument which allows us to investigate the main areas related to circadian rhythm disturbance (sleep/social, activities, and eating pattern) in bipolar disorder.Results and discussionBipolar patients (n = 107) experienced greater biological rhythm alterations than the control group (n = 100) (BRIAN total scores 35.36 ± 7.11 vs. 32.48 ± 6.10, t = 6.912, p = 0.002, Cohen's d = 0.43, r = 0.21). In particular, patients were more impaired than the control group with regard to sleep/social (14.67 ± 4.14 vs. 13.49 ± 2.91, t = 10.61, p = 0.018, Cohen's d = 0.33, r = 0.16) and activity (8.49 ± 2.51 vs. 7.07 ± 2.13, t = 3.90, p = 0.001, Cohen's d = 0.61, r = 0.29) domains. Furthermore, a significant correlation was found between biological rhythms with residual depressive symptoms (r = 0.459, p < 0.001) and functioning (r = 0.432, p < 0.001). These findings suggest a potential link between biological rhythms and the pathophysiology of bipolar disorder. It highlights the importance of novel instruments (e.g., BRIAN) which allow us to assess biological rhythm disturbance in psychiatry. Finally, specific psychosocial interventions focused on lifestyle regularity may be considered as a supplemental treatment of bipolar illness episodes.Electronic supplementary materialThe online version of this article (doi:10.1186/2194-7511-1-6) contains supplementary material, which is available to authorized users.

Impact of Shiftwork on Irritable Bowel Syndrome and Functional Dyspepsia

Disturbances in biological rhythms could lead to unfavorable health impact. This study aimed to evaluate the prevalence of functional dyspepsia (FD) and irritable bowel syndrome (IBS) in rotating shift workers, and to determine the factors that have significant association with the prevalence of FD and IBS. The research had been carried out among nurses and nursing assistants working at Ewha Womans University Mokdong Hospital between December 2010 and February 2011. The subjects completed self-reported questionnaires, including the quality of the sleep and the level of stress. The prevalence of FD and IBS defined by ROME III criteria, and factors associated the disorders in rotating shift workers were compared with those of day workers. A total of 207 subjects were included in the study with 147 rotating shift workers (71.0%), and 60 (29.0%) day workers. The prevalence of IBS in rotating shift workers was higher than that in day workers (32.7% vs 16.7%, P = 0.026). However, no significant difference in the prevalence of FD was observed between the two groups (19.7% vs 20.0%, P = 0.964). In the multivariate analysis, the risk factors for IBS were rotating shift work (OR, 2.36; 95% CI, 1.01-5.47) and poor sleep quality (OR, 4.13; 95% CI, 1.82-9.40), and the risk factors for FD were poor sleep quality (OR, 2.31; 95% CI, 1.01-5.28), and severe stress (OR, 2.19; 95% CI, 1.06-4.76). A higher prevalence of IBS among rotating shift workers could be directly associated with the circadian rhythm disturbance. The circadian rhythm disturbance may be related with the pathogenesis of IBS.

Psychotropic medications affecting biological rhythm

There are many biological rhythms with various time oscillations regulating biological functions in living organisms, mammalians, and humans. Biological rhythms such as circadian, ultradian, and infradian or with longer cycles are independent biological organizations rather than dependent to the external stimulus. Although there is a sustained biological rhythmicity, psychiatric disorders and psychotropic drugs can change this process. The effects of psychotropics on biological rhythmicity can occur via possible neurotransmitter and neuromediator mechanisms within a relatively short time period on the other hand hormonal or genetic mechanisms can impact long term outcome. So far several studies suggested that biological rhythm disturbances play an important role in etiology and course of mood disorders’. Assessment of the possible effects of psychopharmacological agents on biological rhythm is important during the course of mood disorders.

DEPRESSED MOOD IN THE WORKING POPULATION: ASSOCIATIONS WITH WORK SCHEDULES AND WORKING HOURS

The impact of working time arrangements (WTA) on health has been studied extensively. Still, little is known about the interrelation between work schedules, working hours, and depressed mood. For work schedules, the underlying assumptions regarding depressed mood refer to a disturbance of social and biological rhythms, whereas for working hours, the assumptions relate to workload and work capacity. Conversely, depressed mood may urge an employee to adjust his/her work schedule and/or number of working hours/week (h/wk). The aim of this study was to assess the association between work schedule and working hours with depressed mood. Using baseline data from the Maastricht Cohort Study, depressed mood in day work was compared with depressed mood in different shiftwork schedules (n = 8843). Within day work, several categories of working h/wk were studied in association with depressed mood (n = 7217). The association between depressed mood and several aspects of overtime was assessed separately. Depressed mood was measured with a dichotomous item: “Did you feel down every day over the last two weeks?” Separate logistic regression analyses were conducted for men and women, with adjustments for potential confounders. The odds ratio (OR) for depressed mood was greater for men involved in shiftwork than for men only involved in day work (three-shift OR = 2.05 [95% confidence interval, CI 1.52–2.77]; five-shift OR = 1.34 [95% CI 1.00–1.80]; irregular-shift OR = 1.79 [95% CI 1.27–2.53]). In female employees, five-shift work was associated with a higher prevalence of depressed mood (OR = 5.96 [95% CI 2.83–12.56]). Regarding the number of working h/wk, men working <26 h/wk had a higher prevalence of depressed mood than men working 36–40 h/wk (OR = 2.73 [95% CI 1.35–5.52]). After conducting trend analyses, a significant decreasing trend was found in men, whereas an increasing trend was found in women working a high number of hours. Furthermore, a dose-response relationship was present in men regarding the number of overtime h/wk. This study showed that different work schedules and working hours are associated with depressed mood. Shiftwork was related to a higher prevalence of depressed mood than day work. The association was more pronounced for male employees. Regarding the number of working h/wk, male and female employees showed an opposite trend in depressed mood. Because of the possibility of a healthy worker effect and the possibility of a reciprocal relationship between WTA and depressed mood, the reported relation might be underestimated. This study has illustrated that occupational physicians, who deal with depressed mood among workers, should carefully consider the impact of WTA. (Author coorespondence: Karolien.Driesen@epid.unimaas.nl)