Depression symptoms in adulthood could be linked to the season of birth, new research from Kwantlen Polytechnic University (KPU) suggests.
Researchers set out to investigate the link between season of birth and symptoms of depression and anxiety. They discovered a trend: that men had a higher incidence of depression symptoms if born in spring or summer, while women had a higher incidence if born in spring or winter.
The study, which surveyed 303 adults, also showed that of participants with birthdays in the summer season, men had a higher likelihood of depression than women.
“Much of the research literature does not take into account the biological sex of individuals, despite the fact that we know that there are appreciable physiological differences in our biology, such as with hormones. We need to understand that complex interplay between the external environment, our genes, and the state of our internal environment in human health,” says Dr. Mika Mokkonen, a KPU biology instructor and one of the study’s researchers.
“With respect to the main finding in our study about biological males born in the summer, it shows us that there is an interaction between these factors that might not be apparent unless we take these factors into account.”
The article, “Investigating the association between season of birth and symptoms of depression and anxiety in adults,” is published in the open science journal PLOS Mental Health and is co-authored by Mokkonen, KPU student researcher Arshdeep Kaur and KPU biology instructor Dr. Cayley Velazquez.
Study participants ranged in ethnicity, with the majority between 19 and 29 years old.
“This study indicates that we need to look more closely at how the environmental conditions during pregnancy impact an offspring’s future mental health. There is an existing body of research that indicates that prenatal factors can impact the physical health later in life, but we need to better understand how mental health is also impacted,” says Mokkonen.
Such environmental conditions include light exposure, maternal nutrition and seasonal infections.
With some conflicting evidence around the effect of season and birth on mental health, KPU researchers say there is a need for further research with larger samples. Mokkonen says future research should explore genetics, life history characteristics and environmental factors.
“The exciting aspect of this topic is that there are relatively few studies so far, thus we need more attention on the matter, particularly given the direct relevance to human health.”
A KPU Student Research and Innovation Grant supported this study.