Possible contributions of skin pigmentation and vitamin D in a polyfactorial model of seasonal affective disorder
Section snippets
Seasonal affective disorder
Major depressive episodes that follow a seasonal pattern are commonly referred to as seasonal affective disorder (SAD) [1], [2]. SAD involves depressed mood or loss of interest in daily activities, and may include feelings of worthlessness, recurrent thoughts of death, sleep disturbances, fatigue, decreased ability to think, concentrate or make decisions, appetite changes, and/or changes in psychomotor activity level that arise in response to a shorter photoperiod in the fall and winter
Polyfactorial model of SAD
The etiology of SAD is complex and appears to be both polyfactorial and polygenetic [13], [14], [15]. Earlier research suggested that seasonality and depression vulnerability factors, occurring in various combinations may underlie the observed spectrum of seasonal affective symptoms [16], [17]. For example, a preponderance of the seasonality factor along with a minor component of the depression factor was hypothesized to explain sub-syndromal SAD. The converse, predominant depression
Vitamin D
Vitamin D is a pre-steroid hormone that is photosynthesized in the epidermis from 7-dehydrocholesterol through exposure to ultraviolet radiation in the 260–320 nm wavelength range, the UV-B section of the solar ultraviolet (UV) spectrum [32], [33], [34], [35], [36]. The liver metabolizes vitamin D to 25(OH) D3, which is the principal form of vitamin D that circulates in the blood on the key measure of vitamin D status. Further, the kidney converts 25(OH) D3 to the hormone, 1,25 dihydroxyvitamin D
Vitamin D, dopamine and serotonin
Evidence exists that both the dopamine and serotonin neurotransmitter systems are involved in the pathophysiology of SAD. The positive emotion effects of 10,000 lux daily light therapy for people with SAD were reversed comparably by the depletion of serotonin and dopamine in a cross-over study of 16 patients [52]. Similarly, other researchers evaluated the depletion of dopamine in a sample of women with mild seasonality under two different lighting environments (3000 versus 10 lux). Regardless
Vitamin D and the circadian timing system
Gominak and Stumpf [59] maintain that vitamin D is probably one of the phylogenetically oldest steroid hormones in that it links the presence or absence of the sun to the availability of food, to activity levels, and to cycles of rest and sleep. Changes in vitamin D levels according to latitude appear to work at the level of individual genes to affect the adaptation to environmental conditions [63]. The circadian system in mammals regulates activity cycles according to the timing of dawn and
Vitamin D status and depression symptoms
Given its contribution to the dopamine and serotonin neurotransmitter systems and its likely involvement in the circadian system, it is logical to inquire about the relationship of vitamin D status with depression symptoms. In patients with nonseasonal depression or SAD, does the administration of vitamin D provide symptomatic relief? Several cross-sectional studies have reported significantly greater depressive symptoms in groups of older people with varying levels of hypovitaminosis D [69],
Skin pigmentation and vitamin D
Melanin is a derivative of tyrosine and exists in two forms within humans: pheomelanin (red-yellow) and eumelanin (black-brown). Melanin is synthesized in melanosomes that are present in several human tissues that include the epidermis, hair follicles, and the iris. Human skin pigmentation most likely represents the outcome of two antagonistic clines that have evolved through natural selection to adapt human constitutive skin pigmentation to the UV radiation levels that occur as a function of
Summary
Seasonal affective disorder possesses a complex etiology that involves several causal and contributory mechanisms [13], [19]. Vitamin D is a phylogenetically old steroid hormone whose presence researchers have documented in at least 36 tissues and 900 genes as of this writing. Rather than functioning as a causally proximal sub-mechanism in SAD, our review of the literature suggests that the role of vitamin D may be more basic and distal in its contributions to SAD, and to the emergence of other
Hypotheses
We propose a dual-vulnerability conceptualization for the emergence of SAD among people with greater pigmentation who migrate to higher-latitude areas, similar in form to Dealberto’s and McGrath’s approaches for conceptualizing the role of vitamin D in the emergence of schizophrenia and atypical psychoses among first and second-generation immigrants. [56], [82], [83]. Specifically, the first generation of people with dark skin to migrate to high latitude areas may be more likely to exhibit
Conflict of interest statement
None.
References (115)
- et al.
Binge eating disorder in seasonal affective disorder: more than just carbohydrate craving
Psychiatry Res
(2014) - et al.
Prevalence of seasonal affective disorder at four latitudes
Psychiatry Res
(1990) - et al.
Seasonal affective disorder and latitude: a review of the literature
J Affect Disord
(1999) - et al.
Ethnic differences in seasonal affective disorder and associated factors among five immigrant groups in Norway
J Affect Disord
(2013) - et al.
Circadian rhythms and depression: human psychopathology and animal models
Neuropsychopharmacology
(2012) - et al.
The temporal onset of individual symptoms in winter depression: differentiating underlying mechanisms
J Affect Disord
(1991) - et al.
Seasonal depression: the dual vulnerability hypothesis revisited
J Affect Disord
(2001) - et al.
Melanopsin, photosensitive ganglion cells, and seasonal affective disorder
Neurosci Biobehav Rev
(2013) - et al.
Electrophysiological evidence suggesting a seasonal modulation of retinal sensitivity in subsyndromal winter depression
J Affect Disord
(2002) - et al.
A missense variant (P10L) of the melanopsin (OPN4) gene in seasonal affective disorder
J Affect Disord
(2009)
Effect of sunlight and season on serotonin turnover in the brain
Lancet
Bright light exposure during acute tryptophan depletion prevents a lowering of mood in mildly seasonal women
Eur Neuropsychopharmacol
Serotonergic innervation of the hypothalamic suprachiasmatic nucleus and photic regulation of circadian rhythms
Biol Cell
Sunshine-exposure variation of human striatal dopamine D2/D3 receptor availability in healthy volunteers
Prog Neuropsychopharmacol Biol Psychiatry
Environmental factors that influence the cutaneous production of vitamin D1–3
Am J Clin Nutr
Geographic location and vitamin D synthesis
Mol Aspects Med
From vitamin D to hormone D: fundamentals of the vitamin D endocrine system essential for good health
Am J Clin Nutr
Vitamin D, effects on brain development, adult brain function and the links between low levels of vitamin D and neuropsychiatric disease
Front Neuroendocrinol
New clues about vitamin D functions in the nervous system
Trends Endocrinol Metab
Does high UV environment ensure adequate vitamin D status?
J Photochem Photobiol B
The vitamin D receptor in dopamine neurons: its presence in human substantia nigra and its ontogenesis in rat midbrain
Neuroscience
Does ‘imprinting’ with low prenatal vitamin D contribute to the risk of various adult disorders?
Med Hypotheses
Distribution of the vitamin D and 1 a–hydroxylase in human brain
J Chem Neuroanat
Stumpf WE The world epidemic of sleep disorders is linked to vitamin D deficiency
Med Hypotheses
The influence of vitamin D supplementation on melatonin status in patients with multiple sclerosis
Brain Behav Immun
The suprachiasmatic nucleus and the circadian timing system
Prog Mol Biol Transl
Vitamin D-soltriol nuclear binding to neurons of the septal, substriatal, and amygdaloid area in the siberian hamster (Phodopus sungorus) brain
Neuroscience
Serum 25-hydroxyvitamin D levels and the risk of depression: a systematic review and meta-analysis
J Nutr Health Aging
Why are immigrants at increased risk for psychosis? Vitamin D insufficiency, epigenetic mechanisms, or both?
Med Hypotheses
Vitamin D, light, and mental health
J Photochem Photobiol B
Vitamin D: in the evolution of human skin colour
Med Hypotheses
Kinetic and thermodynamic studies of the conversion of previtamin D3 to vitamin D3 in human skin
J Biol Chem
Re-appraisal of current theories for the development and loss of epidural pigmentation in homins and modern humans
J Hum Evol
Diagnostic and statistical manual of mental disorders
Seasonal affective disorder. A description of the syndrome and preliminary findings with light therapy
Arch Gen Psychiatry
Prevalence
Diagnostic assessment
Seasonal affective disorder: a clinical update
Ann Clin Psychiatry
The circadian basis of winter depression
Proc Natl Acad Sci USA
The prevalence of seasonal affective disorder (SAD) in Greenland is related to latitude
Nord J Psychiatry
An overview of epidemiological studies on seasonal affective disorder
Acta Psychiatr Scand
Biological and psychological mechanisms of seasonal affective disorder: a review and integration
Curr Psychiatry Rev
The chronobiology and neurobiology of winter seasonal affective disorder
Dialogues Clin Neurosci
Photoperiodism in humans and other primates: evidence and implications
J Biol Rhythms
The post illumination response is reduced in seasonal affective disorder
Psychiatry Res
Are deficient retinal photoreceptor renewal mechanisms involved in the pathogenesis of winter depression?
Arch Gen Psychiatry
Entrance pupil size predicts retinal illumination in darkly pigmented eyes, but not lightly pigmented eyes
Invest Ophthalmol Vis Sci
Let there be “more” light: enhancement of light actions on the circadian system through non-photic pathways
Prog Neurobiol
The role of dopamine in the pathophysiology of depression
Arch Gen Psychiatry
Cited by (14)
Vitamin D deficiency in a psychiatric population and correlation between vitamin D and CRP
2019, EncephaleCitation Excerpt :Our results showed that vitamin D varied with age, ethnic origin, BMI and the season, results which were expected. Indeed, skin pigmentation affects the absorption of vitamin D [34], and the vitamin D winter measures are lower than those of the summer because UVBs allow the synthesis of vitamin D. Vitamin D serum concentrations have been shown to be inversely correlated with BMI and biochemical markers of adiposity [35]. Among psychiatric patients, the Bazzano et al. study only found ethnic origin as a factor modifying vitamin D among several variables (age, gender, employment, length of hospitalization, addictions, cardiovascular risk factors), which did not include season and BMI [30].
Vitamin d: A pleiotropic hormone with possible psychotropic activities
2021, Current Medicinal ChemistryVitamin D and the athlete-patient: State of the art
2021, Journal of ISAKOS