Overview

• An online survey of 303 adults conducted by Kwantlen Polytechnic University in early 2024 collected demographic data and assessments of anxiety and depression while controlling for age and income.
• Results published in PLOS Mental Health in July 2025 reveal that men born in June, July or August report significantly more depression symptoms compared to men born in other seasons.
• The seasonal birth effect was observed only in biological males and showed no corresponding increase in depression risk among women.
• Authors caution that the study’s small, predominantly student sample and brief two-month data collection period limit causal interpretation and generalizability.
• The research team plans to examine maternal factors such as diet, sunlight exposure, temperature and hormone levels during pregnancy to uncover mechanisms behind the seasonal correlation.