Serum Concentrations of 25-Hydroxyvitamin D and Depression in a General Middle-Aged to Elderly Population in Finland

Can Vıtamın D Reduce the Need for SSRI by Modulatıng Serotonın Synthesıs?: A Revıew of Recent Lıterature

PURPOSE OF REVIEW

This study aims to analyze the effects of vitamin D on serotonin synthesis, release, and function in the brain, and to explore its relationship with various psychiatric disorders.

RECENT FINDINGS

The hormone calcitriol plays a vital role in regulating a multitude of biological processes within the human body. Its deficiency can lead to significant adverse effects on overall health and well-being, including physical and psychological consequences. Evidence indicates that vitamin D may exert influences through receptors in the brain, modulating serotonin production and influencing emotional and cognitive processes. Recent studies propose that elevated serum vitamin D may enhance mood and alleviate depressive states. The impact of vitamin D on cognitive function and behavior remains an area of ongoing investigation. This literature review analyses the available evidence on how vitamin D intake impacts the severity of illness and medication requirements in diverse psychiatric disorders. A review of the literature suggests that there may be a correlation between vitamin D and serotonin, which could potentially contribute to more favorable outcomes in the context of illness. Vitamin D may increase the amount of serotonin in the synaptic gap, which is the intended use of selective serotonin reuptake inhibitors (SSRIs), with its effect on the increase in serotonin release. According to reports, vitamin D supplementation in conjunction with SSRI group medication provides an additive effect for the management of psychiatric disorders.

Vitamin D and depression in older adults: lessons learned from observational and clinical studies

Depression is a mental disorder triggered by the interaction of social, psychological and biological factors that have an important impact on an individual's life. Despite being a well-studied disease with several established forms of treatment, its prevalence is increasing, especially among older adults. New forms of treatment and prevention are encouraged, and some researchers have been discussing the effects of vitamin D (VitD) on depression; however, the exact mechanism by which VitD exerts its effects is not yet conclusive. In this study, we aimed to discuss the possible mechanisms underlying the association between VitD and depression in older adults. Therefore, we conducted a systematic search of databases for indexed articles published until 30 April 2021. The primary focus was on both observational studies documenting the association between VitD and depression/depressive symptoms, and clinical trials documenting the effects of VitD supplementation on depression/depressive symptoms, especially in older adults. Based on pre-clinical, clinical and observational studies, it is suggested that the maintenance of adequate VitD concentrations is an important issue, especially in older adults, which are a risk population for both VitD deficiency and depression. Nevertheless, it is necessary to carry out more studies using longitudinal approaches in low- and middle-income countries to develop a strong source of evidence to formulate guidelines and interventions.

Associations between total dairy, high-fat dairy and low-fat dairy intake, and depressive symptoms: findings from a population-based cross-sectional study

PURPOSE

Evidence on the association between dairy intake and depression is conflicting. Given numerous dietary guidelines recommend the consumption of low-fat dairy products, this study examined associations between total dairy, high-fat dairy, and low-fat dairy intake and the prevalence of elevated depressive symptoms. Associations between dairy products, which differed in both fat content and fermentation status, and depressive symptoms were also explored.

METHODS

This cross-sectional study included 1600 Finnish adults (mean age 63 ± 6 years; 51% female) recruited as part of the Kuopio Ischaemic Heart Disease Risk Factor Study. Dairy intake was assessed using 4-day food records. Elevated depressive symptoms were defined as having a score ≥ 5 on the Diagnostic and Statistical Manual of Mental Disorders-III Depression Scale, and/or regularly using one or more prescription drugs for depressive symptoms.

RESULTS

In total, 166 participants (10.4%) reported having elevated depressive symptoms. Using multivariate logistic regression models, intake in the highest tertile of high-fat dairy products (OR 0.64, 95% CI 0.41-0.998, p trend = 0.04) and high-fat non-fermented dairy products (OR 0.60, 95% CI 0.39-0.92, p trend = 0.02) were associated with reduced odds for having elevated depressive symptoms. Whereas no significant association was observed between intake of total dairy, low-fat dairy, or other dairy products, and depressive symptoms.

CONCLUSION

Higher intake of high-fat dairy and high-fat non-fermented dairy products were associated with reduced odds for having elevated depressive symptoms in middle-aged and older Finnish adults. Given the high global consumption of dairy products, and widespread burden of depression, longitudinal studies that seek to corroborate these findings are required.

Therapeutic and mechanistic intervention of vitamin D in neuropsychiatric disorders

Vitamin D deficiency is believed to affect between 35 and 55% of the world's population, making it a hidden pandemic. In addition to its role in bone and calcium homeostasis, vitamin D has also been linked in preclinical and clinical research to brain function. These outcomes have also been used for a variety of neuropsychiatric and neurodevelopmental problems. Nevertheless, these individuals are more prone to develop signs of cognitive decline. This review will emphasize the association between vitamin D and neuropsychiatric illnesses such as autism, schizophrenia, depression, and Attention Deficit Hyperactivity Disorder (ADHD). While numerous research show vitamin D's essential role in cognitive function in neuropsychiatric illnesses, it is too early to propose its effect on cognitive symptoms with certainty. It is necessary to conduct additional research into the associations between vitamin D deficiency and cognitive abnormalities, particularly those found in autism, schizophrenia, depression, and ADHD, to develop initiatives that address the pressing need for novel and effective preventative therapeutic strategies.

Lower Blood Vitamin D Levels Are Associated with Depressive Symptoms in a Population of Older Adults in Kuwait: A Cross-Sectional Study

Low serum vitamin D has been associated with an increased risk of neuropsychiatry disorders. This study aimed to examine the association between vitamin D deficiency and depression in adults aged 65 years and older. This cross-sectional study was conducted in seven primary healthcare centers across Kuwait (November 2020 to June 2021). The participants (n = 237) had their serum vitamin D 25-(OH)-D concentrations (analyzed by LC-MS) classified as sufficient, ≥75 nmol/L (30 ng/mL); insufficient, 50−75 nmol/L (20−30 ng/mL); or deficient, <50 nmol/L (20 ng/mL). Depressive symptoms were evaluated using the 15-Item Geriatric Depression Scale (15-item GDS). The mean serum 25-OH-D levels (nmol/L) in volunteers with normal, mild, moderate, and severe depression were 100.0 ± 31.7, 71.2 ± 38.6, 58.6 ± 30.1 and 49.0 ± 6.93, respectively (p < 0.001). The participants in the vitamin D sufficiency group were significantly less likely to exhibit depressive symptoms (88.2%) than patients with mild (36%) and moderate (21%) depression (p < 0.001). Ordinal logistic regression showed that vitamin D deficiency (OR = 19.7, 95% CI 5.60, 74.86, p < 0.001) and insufficiency (OR = 6.40, 95% CI 2.20, 19.91, p < 0.001) were associated with higher odds of having depressive symptoms. A low serum vitamin D level is a significant predictor of symptoms of depression among older individuals.

Serum Vitamin D as a Biomarker in Autoimmune, Psychiatric and Neurodegenerative Diseases

Vitamin D is a steroid hormone regulating calcium-phosphorus homeostasis, immune response and brain function. In the past thirty years, an increasing number of cohort studies, meta-analyses and randomized controlled trials (RTCs) evaluated the serum levels of 25-hydroxyvitamin D [25(OH)D], which is considered the Vitamin D status biomarker, in patients affected by neurological, psychiatric and autoimmune diseases. Although an association between low 25(OH)D serum levels and the prevalence of these diseases has been found, it is still unclear whether the serum 25(OH)D measurement can be clinically useful as a biomarker for diagnosis, prognosis and predicting treatment response in neurodegeneration, mental illness and immune-mediated disorders. The lack of standardized data, as well as discrepancies among the studies (in the analytical methods, cut-offs, endpoints and study sets), weakened the findings achieved, hindered pooling data, and, consequently, hampered drawing conclusions. This narrative review summarizes the main findings from the studies performed on serum 25(OH)D in neurological, psychiatric and autoimmune diseases, and clarifies whether or not serum 25(OH)D can be used as a reliable biomarker in these diseases.

Is Vitamin D Important in Anxiety or Depression? What Is the Truth?

PURPOSE OF REVIEW

Depression and anxiety are mood disorders that affect health and therefore quality of life and increase the global burden of disease. One of the possible mechanisms in the pathophysiology of these mood disorders has been reported as oxidative stress and inflammation. In the light of this information, it is important to determine the relationship between antioxidant nutrients (such as vitamin D) and these diseases. There are points where the brain regions involved in the pathophysiology of depression and anxiety and vitamin D metabolism intersect.

RECENT FINDINGS

Low vitamin D levels are associated with increased symptoms of depression and anxiety. For this reason, vitamin D screening should be performed in the prevention and treatment planning of these mood disorders. Vitamin D, which has antioxidant properties and activity in brain tissue, is important for mood disorders preventions or treatments but serum levels must be followed.

Vitamin D, Depressive Symptoms, and Covid-19 Pandemic

Since the COVID-19 outbreak, studies across diverse countries have strongly pointed toward the emergence of a mental health crisis, with a dramatic increase in the prevalence of depressive psychopathology and suicidal tendencies. Vitamin D deficiency has been associated with an increased risk of mental health problems as well as individual responses to stress. Studies have discussed the relationship between low serum vitamin D concentrations and depressive symptoms, suggesting that maintaining adequate concentrations of serum vitamin D seems to have a protective effect against it. Vitamin D was found to contribute to improved serotonergic neurotransmission in the experimental model of depression by regulating serotonin metabolism. The signaling of 1,25-dihydroxyvitamin D3, the active form of vitamin D, through vitamin D receptor (VDR) induces the expression of the gene of tryptophan hydroxylase 2 (TPH2), influences the expression of serotonin reuptake transporter (SERT) as well as the levels of monoamine oxidase-A (MAO-A), the enzyme responsible for serotonin catabolism. Vitamin D also presents a relevant link with chronobiological interplay, which could influence the development of depressive symptoms when unbalance between light-dark cycles occurs. In this Perspective, we discussed the significant role of vitamin D in the elevation of stress-related depressive symptoms during the COVID-19 pandemic. It is suggested that vitamin D monitoring and, when deficiency is detected, supplementation could be considered as an important healthcare measure while lockdown and social isolation procedures last during the COVID-19 pandemic.

Serum Vitamin D and Depressive Symptomatology among Boston-Area Puerto Ricans

BACKGROUND

Low vitamin D status, assessed using serum 25-hydroxyvitamin D [25(OH)D] concentration, has been associated with depression, but research among minority populations, such as Puerto Ricans is limited. We examined the association between serum 25(OH)D and self-reported depressive symptomatology across 3 waves of follow-up in a cohort of Puerto Rican adults residing in Massachusetts.

OBJECTIVES

We evaluated the cross-sectional and longitudinal associations between serum 25(OH)D and self-reported depressive symptoms in the Boston Puerto Rican Health Study (BPRHS) cohort.

METHODS

Participants of the BPRHS were evaluated for depressive symptoms using the Center for Epidemiologic Studies Depression Scale (CES-D). Serum 25(OH)D was measured at baseline (n = 1434), year 2 (n = 1218), and year 5 (n = 914). We categorized serum 25(OH)D concentration as sufficient (≥20 ng/mL), insufficient (12 to <20 ng/mL), and deficient (<12 ng/mL). Multivariable linear regression was used for cross-sectional analyses at baseline, and repeated measures mixed effects modeling was used over 3 waves of follow-up for longitudinal analyses. We conducted sensitivity analyses in vitamin D supplement nonusers and participants with complete data on baseline serum 25(OH)D and CES-D at all 3 visits.

RESULTS

Serum 25(OH)D concentration was not associated with CES-D score in cross-sectional analysis [β = -0.85; 95% CI: -2.80, 1.10 for deficient compared with sufficient 25(OH)D; P-trend = 0.59] or in longitudinal analyses over 5 y [β = -0.41; 95% CI: -1.95, 1.13 for deficient compared with sufficient 25(OH)D; P-trend = 0.93]. Results were similar in sensitivity analyses restricted to vitamin D supplement nonusers (n = 1371) and in analyses conducted in participants with complete measures of baseline serum 25(OH)D and CES-D score at all 3 visits (n = 887) [β = -0.12; 95% CI: -1.98, 1.74 for deficient compared with sufficient 25(OH)D; P-trend = 0.93].

CONCLUSIONS

We did not observe a significant association between serum 25(OH)D and depressive symptomatology in the BPRHS cohort.

Lower serum 25-hydroxycholecalciferol is associated with depressive symptoms in older adults in Southern Brazil

Background

Older adults are one of the most susceptible populations to depression, especially those living in low- and middle-income countries. As well, they are also considering a risk group for vitamin D deficiency. Low serum vitamin D has been associated with an increased risk of brain neuropsychiatry disorders. We aimed to investigate the association between serum 25-hydroxycholecalciferol concentrations and depressive symptoms in adults aged 60 years and over from southern Brazil.

Methods

A cross-sectional analysis was performed using data collected during 2013–2014 from the populational-based longitudinal EpiFloripa Aging Study (n = 1197). Serum 25-hydroxycholecalciferol concentrations were analyzed and classified according to the Endocrine Society reference values [sufficiency (≥ 30 ng/mL), insufficiency (21–29 ng/mL), and deficiency (≤ 20 ng/mL)]. Depressive symptoms were evaluated using the Geriatric Depression Scale (15-item GDS). Logistic regression was performed to assess depressive symptoms in each vitamin D category. The analysis was adjusted for sex, age, skin color, family income, leisure-time physical activities, social or religious groups attendance, morbidities, cognitive impairment, and dependence in activities of daily living.

Results

A total of 557 participants with complete data for exposure and outcome were enrolled in the analysis. Most of the sample participants were female (63.1%), age-range 60–69 years (42.2%), white skin color (85.1%), and vitamin D serum level samples were collected in autumn (50.7%). Depressive symptoms were present in 15.8% of the participants, and the prevalence was higher in individuals classified as deficient in vitamin D (23.2, 95% confidence interval [CI] = 15.6;32.9) and insufficiency (17.2, 95%CI = 11.0;25.9). The crude analysis showed that vitamin D deficient participants had 3.08 (CI = 1.53;6.20) times higher odds to present depressive symptoms compared to vitamin D sufficiency. After adjusting, the association was maintained [OR 2.27 (95%CI = 1.05;4.94).

Conclusions

Serum 25-hydroxycholecalciferol deficiency was positively associated with depressive symptoms in older adults from southern Brazil.

Effects of vitamin D on mood and sleep in the healthy population: Interpretations from the serotonergic pathway

Vitamin D insufficiency is common in the healthy population. Recent insights addressed the role of vitamin D in serotonin and melatonin regulation, suggesting that increasing vitamin D status may be helpful for improving mood and sleep. This literature review covers the current state of evidence regarding potential effects of vitamin D on mood and sleep indicators in healthy people. In total, 11 observational studies were found for sleep, and 54 studies on mood (including ten RCTs). These studies revealed mixed results for both sleep and mood. The findings were interpreted based on the previously proposed serotonergic pathway of vitamin D. Implications and challenges for future research regarding the timing of blood sampling, timing and dosage of supplement intake and investigating the response dynamics are discussed.

Vitamin D serum level in major depressive disorder and schizophrenia

Background

Vitamin D is involved in many brain processes including neurological immune process, regulation of neurological factors, and neuroplasticity. Some studies have linked low serum vitamin D to major depressive disorder (MDD) and schizophrenia, while others have not shown any relationship. The study aimed to assess vitamin D level in patients with depression and those with schizophrenia. Sixty participants were recruited from outpatient clinics of the Institute of Psychiatry, Ain Shams University, Cairo, Egypt. The sample was divided into three groups: group A, 20 patients with MDD; group B, 20 patients with schizophrenia, and group C, 20 healthy control subjects. Ain Shams Psychiatry Clinical Interview was used to gather demographic data, and Structured Clinical interview (SCID-I) and laboratory vitamin D serum levels (ELISA) were applied to subjects.

Results

Eighty-five percent of patients with MDD and 80% of patients with schizophrenia had below normal vitamin D serum level. Compared to controls, vitamin D serum concentration in patients with MDD was statistically significantly lower than controls, while schizophrenia had vitamin D level lower than did control group but higher level than patients with MDD. However, vitamin D level failed to differentiate between patients diagnosed with schizophrenia and those with MDD.

Conclusions

Patients with MDD and those with schizophrenia demonstrated lower vitamin D level compared with health controls. There was no statistically significant difference in vitamin D level between patients with MDD and those with schizophrenia.

Effect of Viewing Video Representation of the Urban Environment and Forest Environment on Mood and Level of Procrastination

A common problem among students is the problem of delaying important work activities, which is conceptualized as procrastination. Since procrastination can cause considerable costs for society, we would like to find a method to effectively alleviate the symptoms of this conditioning. It has been proven in an earlier study that staying in the forest environment increases vitality and reduces anxiety, and the negative state of these features can be associated with the intensification of procrastination symptoms. Therefore, it is likely that watching a forest video may decrease the probability or intensity of procrastination. To measure the impact of the forest environment on the level of procrastination of the subjects, a randomized experiment was carried out, in which the subjects watched in random order (on different days) one of two 15-min videos: one showing a walk in the forest area and one showing a walk in an urban environment (control). We measured the level of so-called 'fluid procrastination' including three aspects: 'lack of energy to do the work', 'inability to get to work' and 'pessimistic attitude to do the work' with a set of questions the respondents completed before and after the experiment. The results showed that one aspect of fluid procrastination ('pessimistic attitude to do the work') can be effectively lowered by watching a video showing the forest environment. In contrast, watching a video of an urban environment increased the procrastination levels for two other aspects of procrastination ('lack of energy to do the work', 'inability to get to work'). We also measured three other parameters before and after the experiment: mood state, restoration and vitality. Watching the video from forest area raised mood and restoration and watching the video from urban area, decreased mood, vitality and restoration. The study suggests that watching a video showing forest landscapes could be used as an effective remedy for problems related to procrastination among students.

Bone Metabolism in Patients Treated for Depression

BACKGROUND

Depression and osteoporosis are severe public health problems. There are conflicting findings regarding the influence of depression on bone metabolism. The aim of the presented study was to compare bone turnover markers and vitamin D levels between patients treated for depression and healthy controls.

PATIENTS AND METHODS

We determined a concentration of osteocalcin, carboxy-terminal telopeptide of type I collagen (β-CTX), 25-hydroxyvitamin D (25OHD) and 1,25(OH)₂D₃ in 99 patients, aged 46.9 ± 11 years, treated for depression, as well as in 45 healthy subjects. Depressive status was determined with the Hamilton Depression Scale (HDRS).

RESULTS

In patients treated for depression, we demonstrated significantly lower osteocalcin concentrations (p < 0.03) and higher concentration of β-CTX (result on the border of significance; p = 0.08). Those relationship were stronger in women. The level of 25OHD and 1,25(OH)₂D₃ did not differ significantly between the examined groups. We observed a negative correlation between the 25OHD and HDRS score after treatment in all patients treated for depression and in subgroups of women and subjects with recurrent depression.

CONCLUSIONS

Our results indicate that depression is related to disturbances in bone metabolism, especially in women and patients with recurrent depression, suggesting its role in context of osteoporosis development.

Vitamin D status was not associated with anxiety, depression, or health-related quality of life in Middle Eastern and African-born immigrants in Sweden

Active vitamin D is a neurosteroid that may modulate brain function. Associations between vitamin D deficiency and depression and anxiety have been demonstrated. We hypothesized that there was an association between anxiety, depression, and health-related quality of life (HRQOL) and vitamin D status. To test this hypothesis, we examined the association between anxiety, depression, and HRQOL and 25-hydroxyvitamin D (25[OH]D) concentrations in the Middle Eastern and African-born immigrant population. All immigrants aged 25-65 years, born in 9 African or Middle Eastern countries, and living in 3 districts in Umeå (n = 1306) were invited, with 195 English- or Swedish-speaking immigrants (104 men and 91 women) participated. Anxiety and depression were measured using the Hospital Anxiety and Depression scale. HRQOL was measured using EuroQoL-5 Dimension 3 Level Questionnaire and EuroQoL Visual Analogue Scale. Serum 25(OH)D was measured using liquid chromatography-tandem mass spectrometry. Associations were determined using logistic and linear regression. Analyses were adjusted for sex, age, origin, socioeconomic factors, lifestyle, chronic diseases, and obesity. In total, 71% had 25(OH)D less than 50 nmol/L and 11% had 25(OH)D less than 25 nmol/L. Anxiety, depression, and HRQOL were not associated with 25(OH)D in the immigrant population. Anxiety was common in female immigrants from the Middle East (32.7%); and after adjustment, lower 25(OH)D concentrations were associated with higher risk of anxiety (25[OH]D ≤ 49 nmol/L vs 25[OH]D ≥ 50 nmol/L: odds ratio 23.2 [95% confidence interval 1.97 - 271.9] P = .012) in this subgroup only; however, reverse causality could not be excluded. In conclusion, the study showed no association between depression, anxiety, or HRQOL and vitamin D status in the immigrant population.

Potential Role of Vitamin D for the Management of Depression and Anxiety

Vitamin D, a fat-soluble vitamin, plays a role not only in calcium and phosphate homeostasis but also in several other functions, including cell growth and neuromuscular and immune function. The deficiency of vitamin D is highly prevalent throughout the world and has been suggested to be associated with an enhanced risk of major depressive disorder (MDD) and anxiety disorders. Therefore, vitamin D supplementation has been investigated for the prevention and treatment of these disorders. This review presents preclinical and clinical evidence of the effects of vitamin D supplementation in these disorders. Although preclinical studies provide limited evidence on the possible mechanisms underlying the beneficial effects of vitamin D for the management of these disorders, most of the clinical studies have indicated that vitamin D supplementation is associated with the reduction of symptoms of depression and anxiety, particularly when the supplementation was carried out in individuals with an MDD diagnosis (of the 13 studies in which MDD diagnosis was established, 12 had positive results with vitamin supplementation). However, some heterogeneity in the outcomes was observed and might be associated with an absence of overt psychiatric symptoms in several studies, genetic polymorphisms that alter vitamin D metabolism and bioavailability, differences in the supplementation regimen (monotherapy, adjunctive therapy, or large bolus dosing), and levels of 25-hydroxyvitamin D₃ (25(OH)D) at baseline (individuals with low vitamin D status may respond better) and attained after supplementation. Additionally, factors such as sex, age, and symptom severity also need to be further explored in relation to the effects of vitamin D. Therefore, although vitamin D may hold significant potential for mental health, further preclinical and clinical studies are clearly necessary to better understand its role on mood/affect modulation.

The prevalence of depressive symptoms in Chinese longevous persons and its correlation with vitamin D status

BACKGROUND

Hypovitaminosis D and depressive syndromes are common conditions in old adults. However, little is known about the relationship between vitamin D and depression in exceptional aged people. The objective of this study is to evaluate the relationship between vitamin D levels and depressive symptoms in Chinese longevous persons.

METHODS

We used a dataset from a cross-sectional survey of a sample of Chinese longevous people with self-reported age 100 or older, including 175 men and 765 women, was conducted from June 2014 to December 2016 in Hainan Province, China. Data on demographics, lifestyle characteristics and health conditions were collected using a structured questionnaire. Anthropometrics and blood samples were obtained following the standard procedure. Depressive symptoms of the participants were assessed using a shortened version of the Geriatric Depression Scale (GDS-15). Serum vitamin D levels were measured using an automated radioimmunoassay.

RESULTS

The prevalence of longevous persons with depressive symptoms among the sample was 32.2% (95% confidence interval: 29.7-34.7%). Serum vitamin D levels were lower in participants with depressive symptoms than in those without (20.8 ± 8.7 vs. 23.7 ± 9.7, ng/mL). Vitamin D deficiency was an independent risk factor for depression after controlling for the potential covariates (Odds ratio = 1.47, 95% Confidence interval = 1.08-2.00; p = 0.014). A negative relationship between serum vitamin D levels and depressive symptoms was also detected, and the relationship remained significant after adjusting for a wide range of other covariates. The multivariate adjusted odds ratio of depressive symptoms for the lowest versus highest quartiles of vitamin D levels was 1.73 (95% confidence interval: 1.10-2.72), and the adjusted odds ratio with a 5 ng/mL decrement of serum 25OHD levels was 1.10 (95% confidence interval: 1.01-1.19).

CONCLUSIONS

This study showed an inverse association between vitamin D levels and depressive symptoms among Chinese longevous persons. Depressive symptoms should be screened in longevous persons who had vitamin D deficiency. Further studies on vitamin D supplement and prevention along with treatment of depression are needed among very old population.

Effect of ultraviolet light on mood, depressive disorders and well-being

BACKGROUND

Human and animal studies have shown that exposure to ultraviolet light can incite a chain of endocrine, immunologic, and neurohumoral reactions that might affect mood. This review focuses on the evidence from clinical trials and observational studies on the effect of ultraviolet light on mood, depressive disorders, and well-being.

METHODS

A search was made in PubMed, Embase, Web of Science, Cochrane, Psychinfo, CINAHL, Academic Search Premier and Science Direct, and the references of key papers, for clinical trials and observational studies describing the effect of ultraviolet light applied to skin or eyes on mood, depressive disorders, and well-being.

RESULTS

Of the seven studies eligible for this review, the effect of ultraviolet light on mood, depressive symptoms and seasonal affective disorders was positive in six of them.

CONCLUSIONS

Of the seven studies, six demonstrated benefit of exposure to ultraviolet radiation and improvement in mood which supports a positive effect of ultraviolet light on mood. Because of the small number of the studies and their heterogeneity, more research is warranted to confirm and document this correlation.