Sleep in seasonal affective disorder

Effects of seasonality in emergency admissions for mental disorders: two years of clinical experience

OBJECTIVES

This retrospective study, conducted in Turin, Italy, between January 2021 and February 2023, investigates the impact of seasonal heatwaves on emergency department (ED) admissions for mental disorders.

METHODS

Through the analysis of data from 2,854 patients, this research found a significant link between the occurrence of heatwaves, especially from June to August, and an elevated rate of ED admissions for psychiatric conditions.

RESULTS

The data indicate a clear seasonal pattern, with admissions peaking during the hot months and diminishing in the colder months. Particularly, the study delineates an enhanced correlation between heatwaves and admissions for severe psychiatric disorders, such as bipolar disorder, major depression, personality disorders, and schizophrenia, accounting for 1,868 of the cases examined. This correlation was most pronounced among individuals aged 50-59 years.

CONCLUSIONS

The results of this study highlight a critical association between the incidence of seasonal heatwaves and an uptick in ED visits for psychiatric disorders, with a distinct impact on severe cases. It underscores the urgency for healthcare systems to anticipate seasonal fluctuations in psychiatric ED admissions and to allocate resources effectively to support patients during peak periods.

Elusive hypersomnolence in seasonal affective disorder: actigraphic and self-reported sleep in and out of depressive episodes

BACKGROUND

Hypersomnolence has been considered a prominent feature of seasonal affective disorder (SAD) despite mixed research findings. In the largest multi-season study conducted to date, we aimed to clarify the nature and extent of hypersomnolence in SAD using multiple measurements during winter depressive episodes and summer remission.

METHODS

Sleep measurements assessed in individuals with SAD and nonseasonal, never-depressed controls included actigraphy, daily sleep diaries, retrospective self-report questionnaires, and self-reported hypersomnia assessed via clinical interviews. To characterize hypersomnolence in SAD we (1) compared sleep between diagnostic groups and seasons, (2) examined correlates of self-reported hypersomnia in SAD, and (3) assessed agreement between commonly used measurement modalities.

RESULTS

In winter compared to summer, individuals with SAD (n = 64) reported sleeping 72 min longer based on clinical interviews (p < 0.001) and 23 min longer based on actigraphy (p = 0.011). Controls (n = 80) did not differ across seasons. There were no seasonal or group differences on total sleep time when assessed by sleep diaries or retrospective self-reports (p's > 0.05). Endorsement of winter hypersomnia in SAD participants was predicted by greater fatigue, total sleep time, time in bed, naps, and later sleep midpoints (p's < 0.05).

CONCLUSION

Despite a winter increase in total sleep time and year-round elevated daytime sleepiness, the average total sleep time (7 h) suggest hypersomnolence is a poor characterization of SAD. Importantly, self-reported hypersomnia captures multiple sleep disruptions, not solely lengthened sleep duration. We recommend using a multimodal assessment of hypersomnolence in mood disorders prior to sleep intervention.

Sleep and circadian rhythm profiles in seasonal depression

Sleep and circadian rhythm disruptions are symptoms of, and hypothesized underlying mechanisms in, seasonal depression. Discrepant observational findings and mixed responses to sleep/circadian-based treatments suggest heterogenous sleep and circadian disruptions in seasonal depression, despite these disruptions historically conceptualized as delayed circadian phase and hypersomnia. This study used a data-driven cluster analysis to characterize sleep/circadian profiles in seasonal depression to identify treatment targets for future interventions. Biobehavioral measures of sleep and circadian rhythms were assessed during the winter in individuals with Seasonal Affective Disorder (SAD), subsyndromal-SAD (S-SAD), or nonseasonal, never depressed controls (total sample N = 103). The following variables were used in the cluster analysis: circadian phase (from dim light melatonin onset), midsleep timing, total sleep time, sleep efficiency, regularity of midsleep timing, and nap duration (all from wrist actigraphy). Sleep and circadian variables were compared across clusters and controls. Despite limited sleep/circadian differences between diagnostic groups, there were two reliable (Jaccard Coefficients >0.75) sleep/circadian profiles in SAD/S-SAD individuals: a 'Disrupted sleep' cluster, characterized by irregular and fragmented sleep and an 'Advanced' cluster, characterized by early sleep and circadian timing and longer total sleep times (>7.5 h). Clusters did not differ by depression severity. Midsleep correlated with DLMO (r = 0.56), irregularity (r = 0.3), and total sleep time (r = -0.27). Sleep and circadian disruptions in seasonal depression are not uniformly characterized by hypersomnia and circadian phase delay. Presence of distinct sleep and circadian subgroups in seasonal depression may predict successful treatment response. Prospective assessment and tailoring of individual sleep and circadian disruptions may reduce treatment failures.

Factors associated with seasonal affective disorders in Lebanese adults

PURPOSE

Evaluate seasonal affective disorder (SAD) and the possible factors associated with it among Lebanese adults, during winter and summer seasons of 2018 and 2019.

DESIGN AND METHODS

Cross-sectional study was conducted in two time intervals. The winter period took place from December 2018 to January 2019, whereas the summer period was from May to June 2019, evaluating the same participants.

FINDINGS

Higher winter depression (adjusted odds ratio [ORa] = 1.16), higher winter insomnia (ORa = 1.04) were significantly associated with higher odds of having winter SAD. Higher summer depression (ORa = 1.20) was significantly associated with higher odds of having summer SAD.

PRACTICE IMPLICATIONS

A proper recognition of risk factors associated with SAD allows the clinician to effectively differentiate between SAD and nonseasonal depressive symptoms.

Childhood maltreatment reports in adult seasonal affective disorder: Associations with sleep disturbances, maladaptive cognitions, and brooding

BACKGROUND

Although childhood maltreatment has been studied in multiple psychopathologies, its role in Seasonal Affective Disorder (SAD) is unknown. The current study examined possible mediators of the relationship between retrospectively-reported childhood maltreatment and adult SAD symptom severity during a major depressive episode in winter.

METHODS

Participants (N = 113), ages 18 to 65, completed measures of childhood maltreatment, SAD severity, sleep disturbances, ruminative brooding, and maladaptive cognitions. Mediation analyses testing the relationship between childhood maltreatment and SAD symptom severity via sleep and cognitive factors were conducted using PROCESS (Hayes, 2012).

RESULTS

Mediation analyses suggested that insomnia, hypersomnia, brooding, and seasonal maladaptive beliefs may account for the association between childhood maltreatment and SAD symptom severity.

LIMITATIONS

Analyses were cross-sectional and should be interpreted with caution. Participants completed self-report childhood trauma measure retrospectively as adults.

CONCLUSION

The present study is the first to examine childhood maltreatment in SAD, a disorder commonly viewed with circadian etiology. Covariance between childhood maltreatment and SAD symptom severity is indirectly explained by sleep difficulties, cognitive factors, and brooding, which may suggest therapeutic targets if replicated in longitudinal or experimental manipulations of sleep and cognition.

Circadian disruption, melatonin rhythm perturbations and their contributions to chaotic physiology

The aim of this report is to summarize the data documenting the vital nature of well-regulated cellular and organismal circadian rhythms, which are also reflected in a stable melatonin cycle, in supporting optimal health. Cellular fluctuations in physiology exist in most cells of multicellular organisms with their stability relying on the prevailing light:dark cycle, since it regulates, via specialized intrinsically-photoreceptive retinal ganglion cells (ipRGC) and the retinohypothalamic tract, the master circadian oscillator, i.e., the suprachiasmatic nuclei (SCN). The output message of the SCN, as determined by the light:dark cycle, is transferred to peripheral oscillators, so-called slave cellular oscillators, directly via the autonomic nervous system with its limited distribution. and indirectly via the pineal-derived circulating melatonin rhythm, which contacts every cell. Via its regulatory effects on the neuroendocrine system, particularly the hypothalamo-pituitary-adrenal axis, the SCN also has a major influence on the adrenal glucocorticoid rhythm which impacts neurological diseases and psychological behaviors. Moreover, the SCN regulates the circadian production and secretion of melatonin. When the central circadian oscillator is disturbed, such as by light at night, it passes misinformation to all organs in the body. When this occurs the physiology of cells becomes altered and normal cellular functions are compromised. This physiological upheaval is a precursor to pathologies. The deterioration of the SCN/pineal network is often a normal consequence of aging and its related diseases, but in today's societies where manufactured light is becoming progressively more common worldwide, the associated pathologies may also be occurring at an earlier age.

Protection of DAergic neurons mediates treadmill running attenuated olfactory deficits and olfactory neurogenesis promotion in depression model

In this study, we aimed to test the effects of treadmill running on depression induced olfactory functions and OB neurogenesis in depression model. Depression model was created with chronic unpredictable mild stress (CUMS) and treadmill running was performed as the antidepressant treatment. Behavioral results showed that treadmill running not only attenuated the depression mood but also improved the olfactory discrimination and sensitivity in CUMS depression model. Immune-staining further indicates treadmill running promoted neurogenesis in hippocampal OB region. Moreover, treadmill running prevented the loss of DAergic neurons in glomerular layer of OB region, indicating the critical role of DAergic neuronal functions in regulating treadmill running mediated olfactory functions. In depression model, inhibiting DAergic neurons by intra-OB injection of 6-OHDA resulted in the compromised improving effects of treadmill running olfactory discrimination. In conclusion, treadmill running could attenuate depression associated olfactory deficits by promoting olfactory neurogenesis and improve DAergic neural functions.