Vitamin D helps the brain produce serotonin, a neurotransmitter critical to emotional health. Vitamin D deficiency can contribute to negative emotions such as depression. Likewise, increased vitamin D consumption elevates mood and promotes a positive outlook.

According to John Cannell, MD, an expert on vitamin D and the staff psychiatrist at a California psychiatric hospital, Vitamin D deficiency contributes to many mood problems. "About 90% of patients in my hospital are vitamin D deficient," says Dr. Cannell, "and I put them on a vitamin D regimen, and it does improve their mood disorders

As staffie said and documented, yes. I can add only the personal anecdotes I have heard, testimonials from people who say it has helped them. there are other benefits of light including those that are merely aesthetic so i advise people to do what seems counterintuitive during depression, turn on the lights and open the shades!

My Vitamin D level is below 15 and the Dr just put me on a very high once a week dose of Vitamin D.. I am in hopes it helps my energy , depression and achs and pains. I have heard a lot of good things about it... The Dr said that sunlight is good but not enough to take care of what you need.. And too much exposure to the sun is not good. So be careful.

It did for me. I was at 10 (deficient). My symptoms were low mood and fatigue. The optimal range is 50 to 60.