Yes, chronic lack of natural sunlight can significantly affect mood, energy, and mental clarity. Sunlight regulates circadian rhythm through retinal light exposure, which anchors cortisol timing in the morning and supports nighttime melatonin release. Without sufficient daylight, especially early in the day, sleep quality, dopamine tone, and serotonin balance can decline. Additionally, reduced UV exposure may lower vitamin D levels, which are linked to immune and mood regulation. Indoor lighting is far dimmer than natural light, so even if you feel fine initially, long-term low sunlight exposure can subtly impair alertness, motivation, and emotional stability.