Vitamin D And Depression In Otherwise Healthy People

Low vitamin D levels are associated with the onset of depression even in young people who have otherwise happy lives. It's not like the doctor will run a blood test and say, "Your vitamin D levels are low. You must be depressed." However, supplemental vitamin D seems to be one way to treat depression, without all the side effects.

Dr. David Kerr of the School of Psychological Science of the College of Liberal Arts at Oregon State University in Corvallis ran a series of assessments of 185 "apparently healthy" young women. He found that about one-third of the women actually displayed some symptoms of depression. One-half of the women in the study had deficiency of vitamin D. The women who had the lowest vitamin D levels were the most likely to display some signs of depression, and to be at risk of a major depressive episode.

"Winter Blues" May Not Be the Real Cause of Depression

Medical researchers first started looking for a link between vitamin D and depression as a way to explain a condition called seasonal affective disorder. As days get gloomier, people get gloomier, especially at high latitudes, including locations like Oregon. Less exposure to sunlight results in lower production of vitamin D, so maybe lack of vitamin D causes depression. The fact that depression also increases during the summer in extremely hot climates where people spend most of the daytime hours indoors in air conditioned places seems to reinforce the theory.

Kerr measured vitamin C and vitamin D levels and gave his 185 volunteers the Center for Epidemiologic Studies Depression (CES-D) scale, a standard psychological test for depression, once a week for four weeks. Since he conducted the study during the fall, the women's vitamin D levels fell throughout the study, and measurements of clinically significant depression rose throughout the study. When he took into account body mass (fat "traps" vitamin D and keeps it from getting into the bloodstream), race (people who have darker skin make less vitamin D), outdoor activity (time in sunshine), and exercise, he found that only two variables were associated with depression, the use of antidepressants (meaning a doctor had diagnosed depression), and vitamin D.

READ Vitamin D - How Much Do We Need And How Do We Get It?

Treat Depression With Vitamin D

This doesn't mean that if you take vitamin D you can throw your antidepressants away. Vitamin D probably won't do the whole job of preventing or treating depression. It takes several weeks or months for vitamin D to accumulate in your body, so the effects may not be immediate. You may need to take supplemental vitamin D all year round even to notice a difference with seasonal affective disorder (the winter blues) in the fall and winter. Vitamin D is not enough. However, taking 1000 IU per day probably will help.

Vitamin D Deficiency May Also Be Associated with Psychosis

The ever-increasing evidence of the role of vitamin D in mental health is not limited to depression. New research suggests that not getting enough vitamin D may also be associated with psychosis, particularly the first "psychotic break" caused by the disease.

Vitamin D deficiency at any stage of life, even before birth, increases the risk of developing psychosis. To see if low vitamin D levels might have something to do with the first appearance of symptoms (most people who develop schizophrenia or another psychosis first "break" in late adolescence or early adulthood), researchers tested vitamin D levels in 166 newly-diagnosed patients at their first admission and 12 months later. They also tested vitamin D levels in 324 patients who had been diagnosed with a psychosis for 15 years or longer.

What the researchers found out was that newly diagnosed patients had an average vitamin D level of 13.64 ng/dl, a lot less than the 20 ng/dl concentration that is considered healthy. Only about 20 percent of newly diagnosed patients had vitamin D levels that would be considered normal. The researchers also discovered that the lower the vitamin D levels, the worse the symptoms.

Vitamin D levels in the 324 long-term schizophrenia patients were even lower, averaging just 12.38 ng/dl. The lower the vitamin D levels, the greater the severity of depression, and the lower the ratings of quality of life.

Does Vitamin D Deficiency Cause Psychosis, Or Is It the Other Way Around?

Researchers did not jump to the conclusion that a deficiency of vitamin D causes psychotic disorders. After all, people who suffer schizophrenia typically don't have outdoor jobs or spend a lot of time lying around on the beach. They usually spend much of their lives indoors, where their bodies do not get much opportunity to make vitamin D from sunlight.

Low vitamin D levels are also associated with overweight (the vitamin tends to stay in fat just underneath the skin rather than circulating through the body), high triglyceride levels, and high blood pressure.  People who have darker skin (which makes less vitamin D), tend to have symptoms that are more severe, although this is not necessarily due to a vitamin deficiency. Not getting enough exercise results in lower vitamin D levels, independently of time spent outside.

All of these issues are about as common among people who have been diagnosed with schizophrenia or another psychosis as they are in the general population. It seems possible that having a severe mental illness causes vitamin D deficiency, rather than the other way around. 

Give Patients Vitamin D Anyway, Researchers Say

The strong possibility that vitamin D does not "cause" schizophrenia does not mean people who have schizophrenia should not be given it. It is also important to prevent osteoporosis and to bolster immunity. Even if the mental illness does not respond directly to vitamin D supplementation, quality of life should be improved.

READ Vitamin D: Who Needs To Take Supplements?

There is one form of dementia that does respond to vitamin D supplements. That is the dementia that often accompanies Parkinson's disease. In people who have Parkinson's, vitamin D slows down the inevitable mental deterioration that comes with the disease. If you or someone you know has Parkinson's, it is a good idea to encourage outdoor activity every day (but not sunburn) and to give vitamin D, at least 1000 IU per day.