Impact of Season of Birth on Psychiatric Disorder Susceptibility and Drug Abuse Incidence in a Population from the Köppen Tropical Savanna Region of Brazil

Abstract

<b><i>Background:</i></b> Despite much evidence that season of birth (SOB) my influence the vulnerability to psychiatric disorders, divergence has been reported, in particular between populations born in the northern and southern hemispheres. We analyzed the potential modified risk by SOB to psychiatric disorder or drug addiction comorbidity in a population born in the Triângulo Mineiro region, a southern hemisphere Köppen tropical savanna region in Brazil. <b><i>Method:</i></b> We accessed the records of 98,457 of patients and healthy controls of the National Datacenter of Medical Promptuary to evaluate the influence of SOB as a modifying factor on the occurrence of mental disorders and drug abuse conditions among individuals born from the year 2000 to 2016. <b><i>Results:</i></b> The data revealed significant modification of the relative incidence of major depressive disorder (MDD) (<i>F</i><sub>11, 72</sub> = 2.898; <i>p</i> = 0.003; eta-squared, ES = 0.313; ⍺ = 0.97), anxiety-related disorder (ARD) (<i>F</i><sub>11, 81 =</sub>2.389; <i>p</i> = 0.013; ES = 0.241; ⍺ = 0.932), and schizophrenia (SZ) (<i>F</i><sub>11, 83</sub> = 2.764; <i>p</i> = 0.005; ES = 0.303; α = 0.963), while there was no increase in the number of healthy controls born in any month of the year (<i>F</i><sub>11, 71</sub> = 1.469; <i>p</i> = 0.163). Post hoc analyses indicated a significant higher vulnerability to MDD or ARD if the patient was born in August, or October to December, respectively. A relative increase in the incidence of SZ was also observed in patients born from August to October, compared to patients born from November to January. <b><i>Conclusions:</i></b> SOB may influence the risk for psychiatric disorders in the TMR population. Regional particularities associated with the climatic regime may account for the apparent divergence between studies.

Month of birth and mental disorders: A population‐based study and validation using global meta‐analysis

“…In a further systematic review, we identified 10 disorders (intellectual disability, ASD, ADHD, schizophrenia, BID, MDD, AUD, Alzheimer's disease, anorexia nervosa, and bulimia nervosa) in 51 articles conducted in 25 countries involving 1 539 811 patients 1,3,5,6,27‐73 . The meta‐analytic results of our findings and included studies are summarized in Table 2.…”

“…In a further systematic review, we identified 10 disorders (intellectual disability, ASD, ADHD, schizophrenia, BID, MDD, AUD, Alzheimer's disease, anorexia nervosa, and bulimia nervosa) in 51 articles conducted in 25 countries involving 1 539 811 patients. 1 , 3 , 5 , 6 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , …”

An epidemiological study of season of birth, mental health, and neuroimaging in the UK Biobank

“…A hemispheric six-month shift has also been observed between seasonality and depression symptoms, with higher scores associating with spring births (March-May) in the Northern hemisphere and autumn births (September-November) in the Southern hemisphere, in a small young adult and adolescent cohort [ 61 ]. Although an excess of August births in MDD patients has also been observed in the Southern hemisphere within a Brazilian retrospective study of MDD cases and controls ( n = 98,457) [ 62 ]. However, no associations between month of birth and depression symptoms were found in a similarly aged cohort in a recent Europe wide study ( n = 72,370) [ 63 ].…”

Seasonality of brain function: role in psychiatric disorders

“…It has been suggested that early light exposure could be beneficial for developing an internal clock that has flexibility to adapt to external circadian challenges [ 136 ] that could partially help explain some reports on the impact of season of birth on psychiatric disorders. Thus, light does not only serve as the major seasonal challenge but also has an impact on our ability to adapt to light changes [ 137 ]. Further, with globalization, more and more people start living far away from where they were born.…”