Season of birth modulates mood seasonality in humans

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.

Birth Month and Course of Recurrent Depressive Disorders in a Polish Population

BACKGROUND The aim of this study was to determine whether the specific season of the year during which the first trimester of pregnancy takes place is significantly associated with the course (intensification and frequency of occurrence) of an episode of recurrent depressive disorder in adult life. MATERIAL AND METHODS We enrolled 184 patients treated for recurrent depressive disorders. RESULTS An analysis of the results obtained indicates that the greatest number of people suffering from a major depressive episode were born in the spring and summer (from April to September), meaning that the first trimester of pregnancy occurred between October and March. However, our results were not statistically significant, perhaps due to the small size of the examined group. CONCLUSIONS The results obtained indicate that birth month may be significantly associated with the course of recurrent depressive disorders. In patients from Central Europe, the first trimester of pregnancy falling in autumn and winter seems to be significant. These results need to be interpreted with caution due to the small size of the examined group.

Eye disorder differentiates seasonality outcomes in persons with severe visual impairment

BACKGROUND

Light plays a crucial role in both the pathogenesis and treatment of seasonal affective disorder (SAD). Consequently decreased retinal sensitivity to light has been suggested to be a risk factor for SAD. In a population of persons with severe visual impairment we recently found a highly increased prevalence of SAD. We now aimed to identify eye disorders or anatomical locations with specific association to seasonality.

METHODS

In 912 cases (33%) from our prior seasonal pattern assessment questionnaire (SPAQ) screening study, we retrieved eye diagnoses from the Danish National Patient Registry and analyzed for specific eye disorders or anatomical locations that significantly differentiated SPAQ outcomes (global seasonality score, (GSS) and SPAQ-SAD prevalence).

RESULTS

Persons with early life eye disorders (congenital conditions or retinopathy of prematurity) reported less symptoms of SAD (median GSS 4.5) than persons with acquired eye disorders (median GSS 5.0, p=0.005). Persons with macular degenerative disorders (MD) had highly increased seasonality outcomes (hazard ratio 2.23, p=0.002, median GSS 5 vs. 8, p=0.01).

LIMITATIONS

the study is a cross-sectional study based on a self-report questionnaire. Register data may be incomplete.

CONCLUSIONS

MD is significantly associated to high-level seasonality and SAD prevalence. Early life eye disorder is associated to slightly lower seasonality compared to acquired eye disorder. Longitudinal studies are needed to assess causality.

Melatonin treatment during early life interacts with restraint to alter neuronal morphology and provoke depressive-like responses

Stressors during early life induce anxiety- and depressive-like responses in adult rodents. Siberian hamsters (Phodopus sungorus) exposed to short days post-weaning also increase adult anxiety- and depressive-like behaviors. To test the hypothesis that melatonin and exposure to stressors early in life interact to alter adult affective responses, we administered melatonin either during the perinatal (gestational day 7 to postnatal day 14) or postnatal (day 15-56) periods and also exposed a subset of dams to restraint during gestation (1 h-2×/day for 4 days). During the final week of injections, depressive-like behaviors were assessed using the sucrose anhedonia and forced swim tests. Hamsters exposed to prenatal restraint and treated with melatonin only during the postnatal period increased depressive-like responses in the forced swim test relative to all other groups. Offspring from restrained dams increased the number of fecal boli produced during the forced swim test, an anxiety-like response. In the present study, prenatal restraint reduced CA1 dendritic branching overall and perinatal melatonin protected hamsters from this restraint-induced reduction. These results suggest that the photoperiodic conditions coincident with birth and early life stressors are important in the development of adult affective responses.

Month of birth and mood seasonality: a comparison between countries in the northern and southern hemispheres

AIMS

A previous study has reported a significant month-of-birth effect on mood seasonality in the northern hemisphere. Higher mood seasonality was observed for university students born during spring or summer months (long photoperiod) compared to those born during autumn or winter months (short photoperiod). The aim of this study was to test the hypothesized photoperiod effect by comparing the correlation between month of birth and mood seasonality in two countries located at the opposite poles of the terrestrial globe: Italy (northern hemisphere) and New Zealand (southern hemisphere). On the basis of the photoperiod-at-birth hypothesis, we expected to find higher mood seasonality among individuals born in months with longer photoperiods in both countries.

METHODS

The Seasonal Pattern Assessment Questionnaire was administered to 1514 young adults (1088 women, 426 men; 1027 Italians, 487 New Zealanders), with ages ranging from 18 to 34 years. The Global Seasonality Score, which is a measure of mood seasonality, was calculated from the Seasonal Pattern Assessment Questionnaire.

RESULTS

A significant overall month-of-birth effect was observed on the Global Seasonality Score, but only for men. Men born in April and August (corresponding in Italy to a long photoperiod, in New Zealand to a short photoperiod) had higher mood seasonality than those born in February, regardless of country.

CONCLUSIONS

A significant month-of-birth effect was found on mood seasonality, but results do not support the hypothesis based on the photoperiod effect.

Season of birth and mood seasonality in late childhood and adolescence

A significant season of birth effect on mood seasonality has been detected in young adults, with higher sensitivity to seasonal changes for people born during spring or summer months (long photoperiod) than those born during autumn or winter months (short photoperiod). The aim of this study was to verify whether the birth season effect on mood seasonality is already present in late childhood and adolescence. To this end, the Seasonal Pattern Assessment Questionnaire for Children and Adolescents (SPAQ-CA) was administered to 1523 Italian participants (870 females, 653 males), ranging from 10 to 17 years of age. The Global Seasonality Score (GSS) was computed as a measure of mood seasonality. Analysis of covariance showed a significant season of birth effect on GSS; although no comparisons were significant when Tukey's posthoc test for unequal samples was performed, it was observed that adolescents born in summer achieved the highest scores while those born in winter obtained the lowest. The present data point out that a significant season of birth effect on mood seasonality is already present in late childhood and adolescence.

Female gender but not season of birth is associated with mood seasonality in a near-equatorial Brazilian city

OBJECTIVE: Studies conducted mainly in countries located in the Northern Hemisphere have shown that season of birth influences mood seasonality. Greater mood seasonality has been observed for individuals born during spring/summer months than those born during autumn/winter months. Expanding past research to the Southern Hemisphere, in this study we examine the influence of season of birth on mood seasonality in a sample of 1,247 healthy young Brazilians. METHOD: The Seasonal Pattern Assessment Questionnaire was used to compute a global seasonality score as a measure of mood seasonality in a cross-sectional study. RESULTS: Analysis of covariance was conducted to examine the effects of month of birth and gender on mood seasonality, with age entered as a covariate. A main effect of gender was observed, F (1, 1197) = 17.86, p < .01; partial Eta-squared = .02, with mood seasonality being higher for females (M = 8) than for males (M = 7). Contradicting previous findings, no significant main effect for month of birth was observed, F (1, 1197) = 0.65, p > .05. CONCLUSION: The unexpected finding is tentatively explained by differences in geographic location and weather fluctuations between the sampling location in Brazil and other countries where season of birth has been found to influence mood seasonality. Additional studies with larger samples from the Southern Hemisphere are necessary to shed additional light on the possible significant influence of season of birth on mood.

Interactions of the serotonin and circadian systems: nature and nurture in rhythms and blues

The serotonin and circadian systems are principal regulatory networks of the brain. Each consists of a unique set of neurons that make widespread neural connections and a defined gene network of transcriptional regulators and signaling genes that subserve serotonergic and circadian function at the genetic level. These master regulatory networks of the brain are extensively intertwined, with reciprocal circuit connections, expression of key genetic elements for serotonin signaling in clock neurons and expression of key clock genes in serotonergic neurons. The reciprocal connections of the serotonin and circadian systems likely have importance for neurobehavioral disorders, as suggested by their convergent contribution to a similar range of mood disorders including seasonal affective disorder (SAD), bipolar disorder, and major depression, and as suggested by their overlapping relationship with the developmental disorder, autism spectrum disorder. Here we review the neuroanatomical and genetic basis for serotonin-circadian interactions in the brain, their potential relationship with neurobehavioral disorders, and recent work examining the effects on the circadian system of genetic perturbation of the serotonergic system as well as the molecular and behavioral effects of developmental imprinting of the circadian system with perinatal seasonal light cycles.

Association between affective temperaments and season of birth in a general student population

BACKGROUND

Several studies indicate a significant association between birth season and personality and neuropsychiatric disorders. The aim of our present study was to investigate the association between affective temperaments and season of birth in a nonclinical sample.

METHODS

366 university students completed the standardized Hungarian version of the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-Auto-questionnaire (TEMPS-A). Ordinary Least Squares regression was applied to explain the relationship between TEMPS-A subscale and birth season of the respondents.

RESULTS

We found a significant association between temperament scores and birth season in the case of the Hyperthymic, Cyclothymic, Irritable and Depressive temperaments, while no significant results emerged for the Anxious temperament.

LIMITATIONS

The relatively small sample size, especially in the case of seasonal and monthly subsamples limits generalization of our results.

CONCLUSIONS

Our results support the evidence that there is a strong association between season of birth and personality, extending the results to affective temperaments as well. Furthermore, our results are in line with clinical observations concerning the seasonal variation of onset and hospitalization due to affective episodes. This is especially important, since affective temperaments are conceived as the subaffective and subclinical manifestations of major and minor affective disorders indicating a risk for the development of these disorders and also exerting a possible pathoplastic effect, thus our results also have clinical significance.

Recurrent otitis media with effusion in preterm infants with histologic chorioamnionitis--a 3 years follow-up study

BACKGROUND

Recurrent otitis media with effusion (OME) is a leading cause of acquired hearing loss in childhood. Histological chorioamnionitis (HCA) is an important cause of preterm delivery and neonatal morbidity and mortality. Here, we tested the hypothesis of an association between recurrent OME during the first 3 years of life and HCA in very low birth weight (VLBW) infants.

METHODS

A total of 110 randomly selected VLBW preterm newborns with HCA and 135 gestational age and gender-matched, HCA-negative VLBW infants were evaluated prospectively during the first 3 years of life for the presence of OME, as diagnosed on the basis of otoscopy, type B or C tympanogram, ipsilateral absence of transient evoked otoacoustic emissions responses, and ipsilaterally increased threshold at diagnostic auditory brain responses evaluation. Potential risk factors for OME were also examined in the two groups.

RESULTS

The HCA-positive infants showed a approximately six times higher frequency of recurrent OME (P<0.0001), increased frequency (>5/yr) of clinical otitis media episodes (P=0.000020), approximately five times higher frequency of adenoid hypertrophy (P<0.00001), a significant seasonal pattern of birth with autumn predominance (P<0.00001), and the first OME occurred earlier (P<0.0001), as compared to the HCA-negative counterparts. Recurrent OME was significantly associated with HCA (O.R.=17.76, 95% CI: 8.98-35.13, P<0.00001), adenoid hypertrophy (O.R.=9.96, 95% CI: 5.17-19.18, P<0.00001), frequency of acute otitis episodes >5/yr (O.R.=8.91, 95% CI: 1.96-40.41, P=0.0005), and birth in autumn (O.R.=5.58, 95% CI: 2.79-11.12, P<0.00001).

CONCLUSIONS

These findings indicate that HCA is a previously unrecognized risk factor for the development of recurrent bilateral OME in VLBW preterm infants during the first 3 years of life.