Depression is treated by vitamin D (when enough is given) – review Oct 2021

Effect of vitamin D supplementation on depression treatment

Assoc. Med. Bras. 67 (8) • Aug 2021 • https://doi.org/10.1590/1806-9282.20210404
Raphaele Teixeira MoreiraLays Arnaud Rosal Lopes RodriguesLuciana Melo de FariasJany de Moura CrisóstomoLayanne Cristina de Carvalho LavôrOnias de Sousa Rodrigues FilhoKaroline de Macêdo Gonçalves Frota

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Depression is a mental disorder that has drawn attention because of its high incidence. The World Health Organization (WHO) reported that the number of cases of depression increased by 18% between 2005 and 2015; 322 million people have depression globally, and most of them are women. In Brazil, depression affects 11.5 million people (5.8% of the population)1.

Depression is characterized by the impairment of the physical and mental states of an individual. Its main symptoms are constant sadness, lack of energy, irritability, anxiety, and loss of interest in activities that usually produce a feeling of pleasure, low self-esteem, and changes in sleep and appetite. For the diagnosis of depression, symptoms should persist for at least 2 weeks2,3.

Depression is also associated with serious disabilities, mortality, and medical expenses. Despite the development of biological, psychological, and environmental theories, the underlying pathophysiology of depression is still unknown and may involve several mechanisms4,5.

There has been a long-standing interest in the role of nutrition and its relationship to depression; some studies have shown a strong relationship between vitamin D and depression. Several dietary factors have been implicated in the development and treatment of depression. The changes in vitamin D receptors impact several brain neurotransmitters and, therefore, suggest a potential role of vitamin D in causing and correcting mood disorders6.

Vitamin D is involved in several brain processes, including neuroimmune regulation, neurotrophic factor regulation, neuroprotection, neuroplasticity, and brain development. Therefore, biologically speaking, this vitamin may be related to depression, and its supplementation may play an important role in the treatment of the disease7,8. Therefore, this study aimed to review the recent literature on the effect of vitamin D supplementation in the treatment of patients with depression.

METHODS
A systematic review of vitamin D supplementation in patients with depression was performed. For the guiding question, the PICO strategy was used, which represents the population (P) to be studied, the intervention (I), comparison (C), and outcome (O). The question to be raised was whether vitamin D supplementation, compared with placebo, helps in the treatment of patients with depression. Each PICO item represents an element: (P) patients with depression, (I) vitamin D supplementation, (C) placebo, and (O) improvements in patient health.

The review was carried out from September to December 2020 and included all articles published up to the time of the research retrieved from the PubMed, SciELO, and ScienceDirect databases. The following combination of descriptors was used in the search for articles: supplementation and (depression or depressive symptoms) and vitamin D registered in the Medical Subject Headings.

Original articles and randomized (RCTs) and placebo-controlled clinical trials addressing vitamin D supplementation in patients with depression with different clinical conditions and at different ages were included. Duplicate original articles and articles that could not be accessed were excluded. The research was registered with the Research Coordination of the UNINOVAFAPI University Center under case number 104/2020.

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol was used to ensure the quality of this study. For the quantitative analysis and risk of methodological bias, the Jadad scale was used to classify articles from 0 to 5 based on the methodological criteria and adequacy of results, and the Cochrane collaboration tool was used to classify articles with a low risk of bias, high risk of bias, and uncertain risk of bias.

RESULTS
The bibliographic research, according to the pre-established strategy, resulted in 830 articles. Of these, 46 were from the PubMed database, 784 were from ScienceDirect, and 0 were from SciELO. After the duplicate article selection and removal process, six original RCTs were identified as eligible for this systematic review. Figure 1 shows the flowchart of the search results for the sources of information and the selection and inclusion of original articles in the systematic review, according to the PRISMA protocol.