Humans and other organisms have adapted to a consistent and predictable 24-h solar cycle, but over the past ∼130 years the widespread adoption of electric light has transformed our environment. Instead of aligning behavioral and physiological processes to the natural solar cycle, individuals respond to artificial light cycles created by social and work schedules. Urban light pollution, night shift work, transmeridian travel, televisions and computers have dramatically altered the timing of light used to entrain biological rhythms. In humans and other mammals, light is detected by the retina and intrinsically photosensitive retinal ganglion cells project this information both to the circadian system and limbic brain regions. Therefore, it is possible that exposure to light at night, which has become pervasive, may disrupt both circadian timing and mood. Notably, the rate of major depression has increased in recent decades, in parallel with increasing exposure to light at night. Strong evidence already links circadian disruption to major depression and other mood disorders. Emerging evidence from the past few years suggests that exposure to light at night also negatively influences mood. In this review, we discuss evidence from recent human and rodent studies supporting the novel hypothesis that nighttime exposure to light disrupts circadian organization and contributes to depressed mood.
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Navara KJ, Nelson RJ . The dark side of light at night: physiological, epidemiological, and ecological consequences. J Pineal Res 2007; 43: 215–224.
Rajaratnam SM, Arendt J . Health in a 24-h society. Lancet 2001; 358: 999–1005.
Karatsoreos IN, McEwen BS . Psychobiological allostasis: resistance, resilience and vulnerability. Trends Cogn Sci 2011; 15: 576–584.
Kessler RC, McGonagle KA, Swartz M, Blazer DG, Nelson CB . Sex and depression in the National Comorbidity Survey. I: Lifetime prevalence, chronicity and recurrence. J Affect Disord 1993; 29: 85–96.
Schmidt TM, Chen SK, Hattar S . Intrinsically photosensitive retinal ganglion cells: many subtypes, diverse functions. Trends Neurosci 2011; 34: 572–580.
Brainard GC, Hanifin JP, Greeson JM, Byrne B, Glickman G, Gerner E et al. Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor. J Neurosci 2001; 21: 6405–6412.
Pauley SM . Lighting for the human circadian clock: recent research indicates that lighting has become a public health issue. Med Hypotheses 2004; 63: 588–596.
Albrecht U, Sun ZS, Eichele G, Lee CC . A differential response of two putative mammalian circadian regulators, mper1 and mper2, to light. Cell 1997; 91: 1055–1064.
Caldelas I, Poirel VJ, Sicard B, Pevet P, Challet E . Circadian profile and photic regulation of clock genes in the suprachiasmatic nucleus of a diurnal mammal Arvicanthis ansorgei. Neuroscience 2003; 116: 583–591.
Hardeland R, Madrid JA, Tan DX, Reiter RJ . Melatonin, the circadian multioscillator system and health: the need for detailed analyses of peripheral melatonin signaling. J Pineal Res 2012; 52: 139–166.
Brainard GC, Lewy AJ, Menaker M, Fredrickson RH, Miller LS, Weleber RG et al. Dose–response relationship between light irradiance and the suppression of plasma melatonin in human volunteers. Brain Res 1988; 454: 212–218.
Brainard GC, Richardson BA, Petterborg LJ, Reiter RJ . The effect of different light intensities on pineal melatonin content. Brain Res 1982; 233: 75–81.
von Gall C, Garabette ML, Kell CA, Frenzel S, Dehghani F, Schumm-Draeger PM et al. Rhythmic gene expression in pituitary depends on heterologous sensitization by the neurohormone melatonin. Nat Neurosci 2002; 5: 234–238.
von Gall C, Weaver DR, Moek J, Jilg A, Stehle JH, Korf HW . Melatonin plays a crucial role in the regulation of rhythmic clock gene expression in the mouse pars tuberalis. Ann N Y Acad Sci 2005; 1040: 508–511.
Bunney WE, Bunney BG . Molecular clock genes in man and lower animals: possible implications for circadian abnormalities in depression. Neuropsychopharmacology 2000; 22: 335–345.
McClung CA . Circadian genes, rhythms and the biology of mood disorders. Pharmacol Ther 2007; 114: 222–232.
McClung CA . Circadian rhythms and mood regulation: insights from pre-clinical models. Eur Neuropsychopharmacol 2011; 21 (Suppl 4): S683–S693.
Rosen LN, Targum SD, Terman M, Bryant MJ, Hoffman H, Kasper SF et al. Prevalence of seasonal affective disorder at four latitudes. Psychiatry Res 1990; 31: 131–144.
Glickman G, Byrne B, Pineda C, Hauck WW, Brainard GC . Light therapy for seasonal affective disorder with blue narrow-band light-emitting diodes (LEDs). Biol Psychiatry 2006; 59: 502–507.
Workman JL, Nelson RJ . Potential animal models of seasonal affective disorder. Neurosci Biobehav Rev 2011; 35: 669–679.
Workman JL, Manny N, Walton JC, Nelson RJ . Short day lengths alter stress and depressive-like responses, and hippocampal morphology in Siberian hamsters. Horm Behav 2011; 60: 520–528.
Ashkenazy T, Einat H, Kronfeld-Schor N . We are in the dark here: induction of depression- and anxiety-like behaviours in the diurnal fat sand rat, by short daylight or melatonin injections. Int J Neuropsychopharmacol 2009; 12: 83–93.
Ashkenazy-Frolinger T, Kronfeld-Schor N, Juetten J, Einat H . It is darkness and not light: depression-like behaviors of diurnal unstriped Nile grass rats maintained under a short photoperiod schedule. J Neurosci Methods 2010; 186: 165–170.
Ashkenazy T, Einat H, Kronfeld-Schor N . Effects of bright light treatment on depression- and anxiety-like behaviors of diurnal rodents maintained on a short daylight schedule. Behav Brain Res 2009; 201: 343–346.
Ma WP, Cao J, Tian M, Cui MH, Han HL, Yang YX et al. Exposure to chronic constant light impairs spatial memory and influences long-term depression in rats. Neurosci Res 2007; 59: 224–230.
Fujioka A, Fujioka T, Tsuruta R, Izumi T, Kasaoka S, Maekawa T . Effects of a constant light environment on hippocampal neurogenesis and memory in mice. Neurosci Lett 2011; 488: 41–44.
Monje FJ, Cabatic M, Divisch I, Kim EJ, Herkner KR, Binder BR et al. Constant darkness induces IL-6-dependent depression-like behavior through the NF-kappaB signaling pathway. J Neurosci 2011; 31: 9075–9083.
Gonzalez MM, Aston-Jones G . Light deprivation damages monoamine neurons and produces a depressive behavioral phenotype in rats. Proc Natl Acad Sci USA 2008; 105: 4898–4903.
Cinzano P, Falchi F, Elvidge CD . The first World Atlas of the artificial night sky brightness. Mon Not R Astron Soc 2001; 328: 689–707.
Brainard GC, Rollag MD, Hanifin JP . Photic regulation of melatonin in humans: ocular and neural signal transduction. J Biol Rhythms 1997; 12: 537–546.
Healy D, Minors DS, Waterhouse JM . Shiftwork, helplessness and depression. J Affect Disord 1993; 29: 17–25.
Stevens RG, Hansen J, Costa G, Haus E, Kauppinen T, Aronson KJ et al. Considerations of circadian impact for defining ‘shift work’ in cancer studies: IARC Working Group Report. Occup Environ Med 2011; 68: 154–162.
Noone P . Nightshift breast cancer, flour dust and blue-light risk. Occup Med (Lond) 2010; 60: 499.
Dunn H, Anderson MA, Hill PD . Nighttime lighting in intensive care units. Crit Care Nurse 2010; 30: 31–37.
Parthasarathy S, Tobin MJ . Sleep in the intensive care unit. Intens Care Med 2004; 30: 197–206.
Bjorksten KS, Bjerregaard P, Kripke DF . Suicides in the midnight sun—a study of seasonality in suicides in West Greenland. Psychiatry Res 2005; 133: 205–213.
Westman JA, Ferketich AK, Kauffman RM, MacEachern SN, Wilkins JR 3rd, Wilcox PP et al. Low cancer incidence rates in Ohio Amish. Cancer Causes Control 2010; 21: 69–75.
Egeland JA, Hostetter AM . Amish Study, I: Affective disorders among the Amish, 1976–1980. Am J Psychiatry 1983; 140: 56–61.
Tsuno N, Besset A, Ritchie K . Sleep and depression. J Clin Psychiatry 2005; 66: 1254–1269.
Goodwin GM, Emsley R, Rembry S, Rouillon F . Agomelatine prevents relapse in patients with major depressive disorder without evidence of a discontinuation syndrome: a 24-week randomized, double-blind, placebo-controlled trial. J Clin Psychiatry 2009; 70: 1128–1137.
Kennedy SH, Rizvi SJ . Agomelatine in the treatment of major depressive disorder: potential for clinical effectiveness. CNS Drugs 2010; 24: 479–499.
Crupi R, Mazzon E, Marino A, La Spada G, Bramanti P, Cuzzocrea S et al. Melatonin treatment mimics the antidepressant action in chronic corticosterone-treated mice. J Pineal Res 2010; 49: 123–129.
Ramirez-Rodriguez G, Klempin F, Babu H, Benitez-King G, Kempermann G . Melatonin modulates cell survival of new neurons in the hippocampus of adult mice. Neuropsychopharmacology 2009; 34: 2180–2191.
Kong X, Li X, Cai Z, Yang N, Liu Y, Shu J et al. Melatonin regulates the viability and differentiation of rat midbrain neural stem cells. Cell Mol Neurobiol 2008; 28: 569–579.
Kuhlman SJ, Silver R, Le Sauter J, Bult-Ito A, McMahon DG . Phase resetting light pulses induce Per1 and persistent spike activity in a subpopulation of biological clock neurons. J Neurosci 2003; 23: 1441–1450.
McEwen BS . Glucocorticoids, depression, and mood disorders: structural remodeling in the brain. Metabolism 2005; 54: 20–23.
Yehuda R, Teicher MH, Trestman RL, Levengood RA, Siever LJ . Cortisol regulation in posttraumatic stress disorder and major depression: a chronobiological analysis. Biol Psychiatry 1996; 40: 79–88.
Scott AJ, Monk TH, Brink LL . Shiftwork as a risk factor for depression: a pilot study. Int J Occup Environ Health 1997; 3: S2–S9.
Czeisler CA, Johnson MP, Duffy JF, Brown EN, Ronda JM, Kronauer RE . Exposure to bright light and darkness to treat physiologic maladaptation to night work. N Engl J Med 1990; 322: 1253–1259.
Katz G, Durst R, Zislin Y, Barel Y, Knobler HY . Psychiatric aspects of jet lag: review and hypothesis. Med Hypotheses 2001; 56: 20–23.
Young DM . Psychiatric morbidity in travelers to Honolulu, Hawaii. Compr Psychiatry 1995; 36: 224–228.
Cho K . Chronic ‘jet lag’ produces temporal lobe atrophy and spatial cognitive deficits. Nat Neurosci 2001; 4: 567–568.
Ohta H, Yamazaki S, McMahon DG . Constant light desynchronizes mammalian clock neurons. Nat Neurosci 2005; 8: 267–269.
Bedrosian TA, Weil ZM, Nelson RJ . Chronic dim light at night provokes reversible depression-like phenotype: possible role for TNF. Mol Psychiatry 2013 (in press).
Bedrosian TA, Galan A, Vaughn CA, Weil ZM, Nelson RJ . Light at night alters daily patterns of cortisol and clock proteins in female siberian hamsters. J Neuroendocrinol 2013 (in press).
Fonken LK, Finy MS, Walton JC, Weil ZM, Workman JL, Ross J et al. Influence of light at night on murine anxiety- and depressive-like responses. Behav Brain Res 2009; 205: 349–354.
Fonken LK, Kitsmiller E, Smale L, Nelson RJ . Dim nighttime light impairs cognition and provokes depressive-like responses in a diurnal rodent. J Biol Rhythms 2012; 27: 319–327.
Bedrosian TA, Fonken LK, Walton JC, Haim A, Nelson RJ . Dim light at night provokes depression-like behaviors and reduces CA1 dendritic spine density in female hamsters. Psychoneuroendocrinology 2011; 36: 1062–1069.
Bedrosian TA, Weil ZM, Nelson RJ . Chronic citalopram treatment ameliorates depressive behavior associated with light at night. Behav Neurosci 2012; 126: 654–658.
Frodl T, Meisenzahl EM, Zetzsche T, Born C, Groll C, Jager M et al. Hippocampal changes in patients with a first episode of major depression. Am J Psychiatry 2002; 159: 1112–1118.
Sheline YI, Sanghavi M, Mintun MA, Gado MH . Depression duration but not age predicts hippocampal volume loss in medically healthy women with recurrent major depression. J Neurosci 1999; 19: 5034–5043.
Bremner JD, Narayan M, Anderson ER, Staib LH, Miller HL, Charney DS . Hippocampal volume reduction in major depression. Am J Psychiatry 2000; 157: 115–118.
Nestler EJ, Barrot M, DiLeone RJ, Eisch AJ, Gold SJ, Monteggia LM . Neurobiology of depression. Neuron 2002; 34: 13–25.
Hajszan T, Dow A, Warner-Schmidt JL, Szigeti-Buck K, Sallam NL, Parducz A et al. Remodeling of hippocampal spine synapses in the rat learned helplessness model of depression. Biol Psychiatry 2009; 65: 392–400.
Hajszan T, MacLusky NJ, Leranth C . Short-term treatment with the antidepressant fluoxetine triggers pyramidal dendritic spine synapse formation in rat hippocampus. Eur J Neurosci 2005; 21: 1299–1303.
Hajszan T, Szigeti-Buck K, Sallam NL, Bober J, Parducz A, Maclusky NJ et al. Effects of estradiol on learned helplessness and associated remodeling of hippocampal spine synapses in female rats. Biol Psychiatry 2010; 67: 168–174.
Duman RS, Monteggia LM . A neurotrophic model for stress-related mood disorders. Biol Psychiatry 2006; 59: 1116–1127.
Maier SF, Watkins LR . Cytokines for psychologists: implications of bidirectional immune-to-brain communication for understanding behavior, mood, and cognition. Psychol Rev 1998; 105: 83–107.
Narasimamurthy R, Hatori M, Nayak SK, Liu F, Panda S, Verma IM . Circadian clock protein cryptochrome regulates the expression of proinflammatory cytokines. Proc Natl Acad Sci USA 2012; 109: 12662–12667.
LeGates TA, Altimus CM, Wang H, Lee HK, Yang S, Zhao H et al. Aberrant light directly impairs mood and learning through melanopsin-expressing neurons. Nature 2012; 491: 594–598.
Hattar S, Kumar M, Park A, Tong P, Tung J, Yau KW et al. Central projections of melanopsin-expressing retinal ganglion cells in the mouse. J Comp Neurol 2006; 497: 326–349.
Bedrosian TA, Vaughn CA, Galan A, Weil ZM, Nelson RJ . Role of melatonin in depressive-like behaviors provoked by chronic light at night, Society for Neuroscience Annual Meeting, 2012, New Orleans p. 94.01.
Compton WM, Conway KP, Stinson FS, Grant BF . Changes in the prevalence of major depression and comorbid substance use disorders in the United States between 1991–1992 and 2001–2002. Am J Psychiatry 2006 163: 2141–2147.
Simon GE, VonKorff M . Reevaluation of secular trends in depression rates. Am J Epidemiol 1992; 135: 1411–1422.
Obayashi K, Saeki K, Iwamoto J, Okamoto N, Tomioka K, Nezu S et al. Exposure to light at night, nocturnal urinary melatonin excretion, and obesity/dyslipidemia in the elderly: a cross-sectional analysis of the HEIJO-KYO study. J Clin Endocrinol Metab 2013; 98: 337–344.
The authors declare no conflict of interest.
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Bedrosian, T., Nelson, R. Influence of the modern light environment on mood. Mol Psychiatry 18, 751–757 (2013). https://doi.org/10.1038/mp.2013.70
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