Some general symptoms of a vitamin deficiency include low energy, depression, irritability, brittle nails, your hair falling out, and also skin issues, such as rashes, acne, or eczema. Lacking any of these vitamins will definitely have a negative effect on your moods. For example, B vitamins are essential to the body's brain and nerve functioning, so you definitely want to make sure you're getting enough of these vitamins in order to feel mentally and physically balanced. Part of why many people are vitamin deficient is because they're eating mostly processed, refined foods, which actually deplete the nutrients and vitamins from your body. I see a lot of my clients go on antidepressants without even looking at what they're eating. Often by just including more fresh, healthy, nutrient-rich foods, they find that their energy increases and their moods will stabilize. Foods like caffeine and sugar are considered non nutritional forms of energy, and these non-nutritional forms of energy actually deplete the vitamins and nutrients from your body. So you want to make sure you're getting enough vitamins and nutrients so you don't experience the symptoms of vitamin deficiency. If you're having a hard time getting the vitamins you need from food, it's a good idea to consider taking vitamin supplements, that way you make sure you get everything you need.