Seasonal affective disorder (SAD) is a type of depression caused by seasonal change that affects about 10% to 20% of the United States population. It begins in the fall and continues for most of winter, but SAD can occasionally occur during spring or summer. The symptoms of the disorder include irritability, tiredness, hypersensitivity to rejection, oversleeping, appetite changes, and weight gain.
People who are at higher risk for seasonal affective disorder include women, young people, those with a family history of the disorder, those with clinical depression or bipolar disorder, and people who live farther from the equator. Patients with severe symptoms take anti-depression medication, but a more common treatment for SAD is light therapy, or phototherapy. By exposing a patient to bright light from the light therapy box, neural chemical changes improve the patient’s mood. The effectiveness of this therapy can be explained by recent patterns discovered in findings about the disorder.
Research suggests that vitamin D could have a regulative role in SAD development. Vitamin D levels in the body change seasonally as a result of changes in the amount of sunlight the body receives. Vitamin D also plays a role in the production of serotonin and dopamine, which are chemicals in the brain that are linked to depression. People with low levels of serotonin and dopamine are more likely to be depressed. Therefore, people with vitamin D deficiency are also more likely to be depressed.
Image Source: Karen Desjardin
Research also shows that the level of skin pigmentation affects vitamin D levels. People with darker skin tend to have lower levels of vitamin D, indicating that greater skin pigmentation correlates with a higher risk of depression.
Michael Kimlin, one of the researchers, says, “What we know now is that there are strong indications that maintaining adequate levels of vitamin D is also important for good mental health. A few minutes of sunlight exposure each day should be enough for most people to maintain an adequate vitamin D status.”
Feature Image Source: Depression by ryan melaugh
