Here’s a list of studies about vitamin D, bright light, and depression:

Role of Vitamin D Supplementation in Patients with Depressive Disorders and Hypovitaminosis D: A Longitudinal Study (2017)

Conclusion: Study of 87 depression patients found that 85% were vitamin D deficient.


High Dose Vitamin D Supplementation Is Associated With a Reduction in Depression Score Among Adolescent Girls: A Nine-Week Follow-Up Study (2017)

Conclusion: To test the effectiveness of vitamin D supplementation for depression treatment 940 adolescent girls were given 50,000 IU of vitamin D weekly for 9 straight weeks. At the end of the study researchers found that was a significant reduction in the depression scores of the group. “Our results suggest that supplementation with vitamin D may improve depressive symptoms among adolescent girls.”


Vitamin D Supplementation Improves Mood in Women with Type 2 Diabetes (2017)

Conclusion: 46 women suffering from type 2 diabetes and significant depression were given a weekly dose of 50,000 IU vitamin D2 for 6 months. The patients experienced a significant reduction in depression and anxiety.


A Randomized Controlled Trial of Vitamin D Supplementation on Perinatal Depression: In Iranian Pregnant Mothers (2016)

Conclusion: This randomized control trial study split 169 pregnant Iranian women in their third trimester into two groups. One group received a placebo, the other received 2,000 IU of vitamin D3 daily for the duration of their pregnancy. Compared to the placebo group, the mothers receiving vitamin D had higher vitamin D levels and lower depression scores during the last month of pregnancy and the two months after childbirth. “The present trial showed that consuming 2000 IU vitamin D3 daily during late pregnancy was effective in decreasing perinatal depression levels.” Alarmingly, this study also found that 72% of the mothers were suffering from vitamin D-deficiency at baseline.
Note: much research has shown that 2,000 IU of vitamin D3 is inadequate for adults who don’t get much unprotected sun exposure. One wonders how much better the depression scores would have been with 5,000 IU of vitamin D daily.


Serum 25-Hydroxyvitamin D Concentrations and Depressive Symptoms Among Young Adult Men and Women (2014)

Conclusion: A study of 615 young adults found that those with lower vitamin D levels had worse depression scores.


Suicidal Patients are Deficient in Vitamin D, Associated with a Pro-Inflammatory Status in the Blood (2014)

Conclusion: 59 suicide attempters were enrolled in a study and tested for their vitamin D status along with non-suicidal depressed people and non-depressed healthy control subjects. 58% of the suicide attempters were clinically deficient in vitamin D and had lower levels than than the non-suicidal depressed subjects and non-depressed, healthy control subjects.


The Association between Serum 25-Hydroxyvitamin D Concentrations and Depressive Symptoms in Korean Adults: Findings from the Fifth Korea National Health and Nutrition Examination Survey 2010 (2014)

Conclusion: Study of 3,570 Korean adults found that those reporting having depression symptoms had lower vitamin D levels compared to those who did not report any depression.


Low Serum 25-Hydroxyvitamin D Concentrations Are Associated with Increased Likelihood of Having Depressive Symptoms Among Japanese Workers (2014)

Conclusion: 1,786 Japanese workers were evaluated for vitamin D levels and depression. 92% of subjects had inadequate vitamin D levels. Researchers found that those with lower vitamin D levels had higher rates of depression than workers with higher vitamin D levels. “Results suggest that lower concentrations of circulating vitamin D are associated with increased likelihood of having depressive symptoms among apparently healthy workers.”


Depressed Adolescents in a Case-Series were Low in Vitamin D and Depression was Ameliorated by Vitamin D Supplementation (2012)

Conclusion: 48 vitamin D-deficient Swedish teenagers being treated for depression were put on a vitamin D supplementation regimen for 3 months. At the end of the study there was a significant improvement in their scores for depression , irritability, tiredness, mood swings, sleep problems, fatigue, inability to concentrate, and pain. “This study showed low levels of vitamin D in 54 depressed adolescents, positive correlation between vitamin D and well‐being, and improved symptoms related to depression and vitamin D deficiency after vitamin D supplementation.”


Association Between Low Serum 25-Hydroxyvitamin D and Depression in a Large Sample of Healthy Adults: The Cooper Center Longitudinal Study (2011)

Conclusion: Longitudinal study evaluated the vitamin D levels and depression incidence of 12,594 participants. Researchers found that those with lower vitamin D levels had higher rates of depression. “We found that low vitamin D levels are associated with depressive symptoms, especially in persons with a history of depression.”


Depression is Associated with Decreased 25-Hydroxyvitamin D and Increased Parathyroid Hormone Levels in Older Adults (2008)

Conclusion: A study of 1,282 Dutch elderly people found that those who reported having minor and major depression had lower vitamin D levels compared to the rest of the participants.


Effects of Vitamin D Supplementation on Symptoms of Depression in Overweight and Obese Subjects: Randomized Double Blind Trial (2008)

Conclusion: 441 obese participants were enrolled into a randomized, double-blind, placebo-controlled trial testing the effectiveness of vitamin D for depression. Subjects were given either 20,000 IU vitamin D weekly for one year, 40,000 IU weekly for one year, or placebo weekly for one year. At the end of the study those in the vitamin D groups exhibited improved depression scores, but the placebo group did not. Those with lower vitamin D levels were also found to score worse depression scores compared to those with higher vitamin D levels.


Vitamin D Deficiency is Associated with Low Mood and Worse Cognitive Performance in Older Adults (2006)

Conclusion: A study of 80 older adults found that 58% had inadequate vitamin D levels and those with lower levels had worse scores on depression and cognitive function tests.


Neuropsychological Function in Relation to Serum Parathyroid Hormone and Serum 25-Hydroxyvitamin D Levels. The Tromsø Study. (2006)

Conclusion: This study of 21 patients suffering from secondary hyperparathyroidism found that they had lower vitamin D levels compared to 63 control subjects. Those with lower vitamin D levels also had a higher depression score.


Effect of Sunlight and Season on Serotonin Turnover in the Brain (2002)

Conclusion: A study of 101 healthy men found that their serotonin levels were lowest during winter, when there’s less sunlight, but “rose rapidly” as the amount of bright sunlight increased.


Bright Light Therapy and/or Imipramine for Inpatients with Recurrent Non-Seasonal Depression (2002)

Conclusion: This experiment involving 34 adult in-patients suffering from non-seasonal major depressive order split the patients into three groups to compare the 3-week treatment effectiveness of the following: A) bright light therapy combined with the antidepressant drug imipramine, B) bright light therapy combined with a placebo antidepressant pill, and C) imipramine combined with placebo light therapy. All three groups enjoyed significant improvement, but, AMAZINGLY, just bright light therapy alone (B) was found to be superior to just imipramine (C), as well as the combination of imipramine/bright light (A).


Impact of UVA Exposure on Psychological Parameters and Circulating Serotonin and Melatonin (2002)

Conclusion: This study found that subjects who underwent a UVA irradiation session twice a week for three weeks tested as having higher serotonin levels and lower melatonin levels compared to a control group. The UVA-irradiated group also reported feeling “significantly more balanced, less nervous, more strengthened, and more satisfied with their appearance.” So although you can’t get vitamin D from UVA, this study demonstrates that there are still health benefits of UVA exposure and bright light and that it’s not a bad idea to enjoy a balance of full-spectrum sunlight.


Light Treatment for Nonseasonal Depression: Speed, Efficacy, and Combined Treatment (1998)

Conclusion: Bright light treatment was found to alleviate depression faster than medication. (You know… like SUNLIGHT)


Morning vs Evening Light Treatment of Patients with Winter Depression (1998)

Conclusion: Morning bright light therapy is more effective as an antidepressant compared to evening bright light therapy. (Yep, the sun rises in the morning.)


Bone Mineral Density in Women with Depression (1996)

Conclusion: Compared to normal women, depressed women tend to have lower bone mineral density. Both depression and lower bone mineral density are symptoms of vitamin D deficiency.


Sunny Rooms Expedite Recovery From Severe and Refractory Depressions (1996)

Conclusion: A psychiatric clinic noticed over a period of time that their depressed patients staying in the brighter, sunnier hospital rooms recovered faster than patients staying in dully lit rooms. They looked over their records and realized that the depressed patients in sunny rooms stayed 16.9 days, whereas the depressed patients staying in the dully lit rooms stayed 19.5 days. The patients in the sunny rooms were inadvertently receiving bright light therapy, which has been proven to be an effective treatment for depression.



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