iron and vitamin d deficiency can cause depression. i’m dead serious bc i have been disabled from chronic fatigue for years and that was even after getting tested!!! turns out normal ranges are still deficient. ferritin should be above 100 and vitamin d above 110. i do not play about fatigue, depression, or nutrient deficiencies. it can be a matter of life and death. iron deficiency can give you heart attacks. nothing funny about being too fatigued to talk.