Blue light from screen and depression – A review

Introduction. The growing prevalence of screen time in modern societies has significantly increased exposure to blue light,especially from smartphones and computers. While blue light is crucial for circadian rhythm regulation and mood enhancement during the day, its excessive evening exposure may negatively impact sleep quality and emotional stability. Recent studies have pointed toward its potential link with the development of depressive symptoms. Aim. This review aims to explore the relationship between exposure to blue light particularly from screen-based devices and the development or exacerbation of depressive symptoms, with a focus on biological mechanisms, epidemiological data, and the therapeutic potential of light in mood disorders. Material and methods. A narrative review of 113 articles retrieved from PubMed and open-access sources (published up to May 2025) was conducted. The included literature covered neurobiological mechanisms (e.g., melanopsin, ipRGCs), circadian rhythm alterations, clinical trials on light therapy, and epidemiological studies linking screen time with depression. Emphasis was placed on studies investigating adolescent and adult populations, blue light wavelength sensitivity, and melatonin suppression. Conclusions. Blue light influences human physiology through melanopsin-expressing retinal ganglion cells, affecting melatonin secretion and circadian rhythms. While daytime exposure supports mood and cognitive performance, evening exposure is associated with sleep disturbances and an increased risk of depressive symptoms. Bright light therapy shows promising efficacy in treating seasonal affective disorder and may support mood regulation in broader populations.