1
|
Roecklein KA, Franzen PL, Wescott DL, Hasler BP, Miller MA, Donofry SD, DuPont CM, Gratzmiller SM, Drexler SP, Wood-Vasey WM, Gamlin PD. Melanopsin-driven pupil response in summer and winter in unipolar seasonal affective disorder. J Affect Disord 2021; 291:93-101. [PMID: 34029883 PMCID: PMC8693789 DOI: 10.1016/j.jad.2021.04.084] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 02/19/2021] [Accepted: 04/25/2021] [Indexed: 11/30/2022]
Abstract
A retinal subsensitivity to environmental light may trigger Seasonal Affective Disorder (SAD) under low wintertime light conditions. The main aim of this study was to assess the responses of melanopsin-containing retinal ganglion cells in participants (N= 65) diagnosed with unipolar SAD compared to controls with no history of depression. Participants attended a summer visit, a winter visit, or both. Retinal responses to light were measured using the post-illumination pupil response (PIPR) to assess melanopsin-driven responses in the non-visual light input pathway. Linear mixed-effects modeling was used to test a group*season interaction on the Net PIPR (red minus blue light response, percent baseline). We observed a significant group*season interaction such that the PIPR decreased from summer to winter significantly in the SAD group while not in the control group. The SAD group PIPR was significantly lower in winter compared to controls but did not differ between groups in summer. Only 60% of the participants underwent an eye health exam, although all participants reported no history of retinal pathology, and eye exam status was neither associated with outcome nor different between groups. This seasonal variation in melanopsin driven non-visual responses to light may be a risk factor for SAD, and further highlights individual differences in responses to light for direct or indirect effects of light on mood.
Collapse
Affiliation(s)
- Kathryn A. Roecklein
- Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,The Center for the Neural Basis of Cognition, Pittsburgh, Pennsylvania, USA.,Corresponding Author:Kathryn A. Roecklein, Ph.D. Associate Professor Department of Psychology, University of Pittsburgh 210 S. Bouquet Street Pittsburgh, PA 15206 (412) 624-4553
| | - Peter L. Franzen
- Department of Psychiatry, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Delainey L. Wescott
- Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Brant P. Hasler
- Department of Psychiatry, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Megan A. Miller
- Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Shannon D. Donofry
- Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Caitlin M. DuPont
- Department of Psychology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Sarah M. Gratzmiller
- Department of Psychiatry, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Scott P. Drexler
- Department of Ophthalmology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - W. Michael Wood-Vasey
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Paul D. Gamlin
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA
| |
Collapse
|
2
|
Silverstein SM, Demmin DL, Schallek JB, Fradkin SI. Measures of Retinal Structure and Function as Biomarkers in Neurology and Psychiatry. Biomark Neuropsychiatry 2020. [DOI: 10.1016/j.bionps.2020.100018] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
|
3
|
Münch M, Ladaique M, Roemer S, Hashemi K, Kawasaki A. Melanopsin-Mediated Acute Light Responses Measured in Winter and in Summer: Seasonal Variations in Adults with and without Cataracts. Front Neurol 2017; 8:464. [PMID: 28955293 PMCID: PMC5601987 DOI: 10.3389/fneur.2017.00464] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 08/21/2017] [Indexed: 11/19/2022] Open
Abstract
Seasonal adaptation is a ubiquitous behavior seen in many species on both global hemispheres and is conveyed by changing photoperiods. In humans this seasonal adaptation is less apparent, in part because changes in daylength are masked by the use of electrical lighting at night. On the other hand, cataracts which reduce light transmission, may compound seasonal changes related to the reduced daylength of winter. To better understand the effects of different photoperiod lengths in healthy adults without and with cataracts, we tested their melanopsin-mediated light responses in summer vs. winter. Fifty-two participants (mean age 67.4 years; 30 with bilateral cataracts and 22 age-matched controls with clear lenses; pseudophakes) were tested twice, once in summer and once in winter. At each test session we assessed the electroretinogram and pupil responses during daytime and we determined melatonin suppression, subjective sleepiness and mood in response to light exposure in the evening. Circadian rest-activity cycles and sleep from activity recordings were also analyzed for both seasons. Both groups had similar visual function. There were no seasonal differences in the electroretinogram. For the pupil responses to bright blue light, the post-illumination pupil response (PIPR) was greater in winter than summer in pseudophakes, but not in cataract participants, whereas melatonin suppression to acute light exposure showed no differences between both groups and seasons. Overall, intra-daily variability of rest-activity was worse in winter but participants felt sleepier and reported worse mood at the laboratory in evening time in the summer. Those with cataracts had poorer sleep quality with lower sleep efficiency, and higher activity during sleep in winter than summer. In this study, the PIPR showed a seasonal variation in which a larger response was found during winter. This variation was only detected in participants with a clear intraocular lens. In the cataract group, visual function was not impaired yet these participants showed a lack of seasonal changes in the pupil response to blue light and poorer sleep in winter. These findings raise the question for tailored lighting conditions for cataract patients in order to counter potentially deleterious effects of living with chronically lower light exposure.
Collapse
Affiliation(s)
- Mirjam Münch
- Group Sleep Research & Clinical Chronobiology, Institute of Physiology, Charité University Médicine Berlin, Berlin, Germany
| | - Myriam Ladaique
- Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland
| | - Ségolène Roemer
- Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland
| | - Kattayoon Hashemi
- Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland
| | - Aki Kawasaki
- Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland
| |
Collapse
|
4
|
Stewart AE, Roecklein KA, Tanner S, Kimlin MG. Possible contributions of skin pigmentation and vitamin D in a polyfactorial model of seasonal affective disorder. Med Hypotheses 2014; 83:517-25. [PMID: 25270233 DOI: 10.1016/j.mehy.2014.09.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 08/07/2014] [Accepted: 09/10/2014] [Indexed: 01/01/2023]
Abstract
Seasonal affective disorder (SAD) is a polyfactorial and polygenetic disorder that involves biological and psychological sub-mechanisms that differentially involve depression, seasonality, circadian rhythms, retinal sensitivity, iris pigmentation, sleep factors, and the neurotransmitters involved with these systems. Within the framework of the polyfactorial conceptualization of SAD, we review the possible contributions of vitamin D3 with respect to the aforementioned sub-mechanisms. We hypothesize that rather than functioning primarily as a proximal or direct sub-mechanism in the etiology of SAD, vitamin D likely functions in a more foundational and regulative role in potentiating the sub-mechanisms associated with the depressive and seasonality factors. There are several reasons for this position: 1. vitamin D levels fluctuate in the body seasonally, with a lag, in direct relation to seasonally-available sunlight; 2. lower vitamin D levels have been observed in depressed patients (as well as in patients with other psychiatric disorders) compared to controls; 3. vitamin D levels in the central nervous system affect the production of both serotonin and dopamine; and 4. vitamin D and vitamin D responsive elements are found throughout the midbrain regions and are especially concentrated in the hypothalamus, a region that encompasses the circadian timing systems and much of its neural circuitry. We also consider the variable of skin pigmentation as this may affect levels of vitamin D in the body. We hypothesize that people with darker skin pigmentation may experience greater risks for lower vitamin D levels that, especially following their migration to regions of higher latitude, could contribute to the emergence of SAD and other psychiatric and physical health problems.
Collapse
|
5
|
Roecklein K, Wong P, Ernecoff N, Miller M, Donofry S, Kamarck M, Wood-Vasey WM, Franzen P. The post illumination pupil response is reduced in seasonal affective disorder. Psychiatry Res 2013; 210:150-8. [PMID: 23809464 PMCID: PMC3795919 DOI: 10.1016/j.psychres.2013.05.023] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 05/15/2013] [Accepted: 05/19/2013] [Indexed: 10/26/2022]
Abstract
Individuals with seasonal affective disorder (SAD) may have a decreased retinal sensitivity in the non-image forming light-input pathway. We examined the post illumination pupil response (PIPR) among individuals with SAD and healthy controls to identify possible differences in the melanopsin signaling pathway. We also investigated whether melanopsin gene (OPN4) variations would predict variability in the PIPR. Fifteen SAD and 15 control participants (80% women, mean age 36.7 years, S.D.=14.5) were assessed in the fall/winter. Participants were diagnosed based on DSM-IV-TR criteria. Infrared pupillometry was used to measure pupil diameter prior to, during, and after red and blue stimuli. In response to blue light, the SAD group had a reduced PIPR and a lower PIPR percent change relative to controls. The PIPR after the blue stimulus also varied on the basis of OPN4 I394T genotype, but not OPN4 P10L genotype. These findings may indicate that individuals with SAD have a less sensitive light input pathway as measured by the PIPR, leading to differences in neurobiological and behavioral responses such as alertness, circadian photoentrainment, and melatonin release. In addition, this sensitivity may vary based on sequence variations in OPN4, although a larger sample and replication is needed.
Collapse
Affiliation(s)
- Kathryn Roecklein
- Department of Psychology, University of Pittsburgh, 201S Bouquet St, Pittsburgh, PA 15260, USA.
| | - Patricia Wong
- Department of Psychology, University of Pittsburgh, 201 S Bouquet St, Pittsburgh, PA 15260, USA
| | - Natalie Ernecoff
- Department of Psychology, University of Pittsburgh, 201 S Bouquet St, Pittsburgh, PA 15260, USA
| | - Megan Miller
- Department of Psychology, University of Pittsburgh, 201 S Bouquet St, Pittsburgh, PA 15260, USA
| | - Shannon Donofry
- Department of Psychology, University of Pittsburgh, 201 S Bouquet St, Pittsburgh, PA 15260, USA
| | - Marissa Kamarck
- Department of Psychology, University of Pittsburgh, 201 S Bouquet St, Pittsburgh, PA 15260, USA
| | | | - Peter Franzen
- Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh PA, USA
| |
Collapse
|
6
|
Roecklein KA, Wong PM, Miller MA, Donofry SD, Kamarck ML, Brainard GC. Melanopsin, photosensitive ganglion cells, and seasonal affective disorder. Neurosci Biobehav Rev 2012; 37:229-39. [PMID: 23286902 DOI: 10.1016/j.neubiorev.2012.12.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 11/05/2012] [Accepted: 12/21/2012] [Indexed: 02/05/2023]
Abstract
In two recent reports, melanopsin gene variations were associated with seasonal affective disorder (SAD), and in changes in the timing of sleep and activity in healthy individuals. New studies have deepened our understanding of the retinohypothalamic tract, which translates environmental light received by the retina into neural signals sent to a set of nonvisual nuclei in the brain that are responsible for functions other than sight including circadian, neuroendocrine and neurobehavioral regulation. Because this pathway mediates seasonal changes in physiology, behavior, and mood, individual variations in the pathway may explain why approximately 1-2% of the North American population develops mood disorders with a seasonal pattern (i.e., Major Depressive and Bipolar Disorders with a seasonal pattern, also known as seasonal affective disorder/SAD). Components of depression including mood changes, sleep patterns, appetite, and cognitive performance can be affected by the biological and behavioral responses to light. Specifically, variations in the gene sequence for the retinal photopigment, melanopsin, may be responsible for significant increased risk for mood disorders with a seasonal pattern, and may do so by leading to changes in activity and sleep timing in winter. The retinal sensitivity of SAD is hypothesized to be decreased compared to controls, and that further decrements in winter light levels may combine to trigger depression in winter. Here we outline steps for new research to address the possible role of melanopsin in seasonal affective disorder including chromatic pupillometry designed to measure the sensitivity of melanopsin containing retinal ganglion cells.
Collapse
Affiliation(s)
- Kathryn A Roecklein
- Department of Psychology, University of Pittsburgh, 3500 Sennott Square, 210 South Bouquet St., Pittsburgh, PA 15260, USA.
| | | | | | | | | | | |
Collapse
|
7
|
Gordijn MCM, 't Mannetje D, Meesters Y. The effects of blue-enriched light treatment compared to standard light treatment in Seasonal Affective Disorder. J Affect Disord 2012; 136:72-80. [PMID: 21911257 DOI: 10.1016/j.jad.2011.08.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 08/14/2011] [Accepted: 08/16/2011] [Indexed: 10/17/2022]
Abstract
BACKGROUND One of the most frequently investigated hypotheses of the pathophysiology underlying Seasonal Affective Disorder (SAD) is a disturbance of circadian rhythms. Since the circadian system as well as other non-visual effects is especially sensitive to blue light, a new light therapy device with blue enriched polychromatic light was tested for its efficacy to treat SAD. METHODS Within one winter 52 patients were treated in one of three conditions: 30 min full spectrum light (9000 lx, 5000 K), 30 min blue-enriched light (9000 lx, 17,000 K), or 20 min blue-enriched light. The study lasted 22 days with 10 days of morning-light treatment on weekdays during the first 2 weeks. RESULTS Depressive symptoms (SIGH SAD) diminished over the 3-week period in all conditions, with no significant differences between conditions. The percentage responders were high, differing from 75%, 59% and 71% for the standard-LT, 30 min blue-enriched-LT, and 20 min blue-enriched-LT, respectively. CONCLUSION The lack of superiority of high intensity blue-enriched light over standard bright light treatment does not clearly support nor rule out the possibility of an important role for the circadian system or the blue sensitive non-visual image forming system in general, in the pathophysiology of SAD. The lack of a difference between conditions may also be the result of a saturated response to the high light intensities used. Recent data indeed suggest that low intensity blue-enriched light may be as effective as standard bright light treatment. The possibility of improving light therapy for SAD patients by applying light of shorter duration or at lower light intensities is highly relevant for optimizing treatment and will help to clarify the role of the circadian system and/or the non-image forming photoreceptors in SAD pathophysiology. CLINICAL TRIAL https://register.clinicaltrials.gov: NCT01048294.
Collapse
Affiliation(s)
- M C M Gordijn
- Department of Psychiatry, University Medical Center Groningen, The Netherlands.
| | - D 't Mannetje
- Department of Psychiatry, University Medical Center Groningen, The Netherlands
| | - Y Meesters
- Department of Psychiatry, University Medical Center Groningen, The Netherlands
| |
Collapse
|
8
|
Gagné AM, Hébert M. Atypical pattern of rod electroretinogram modulation by recent light history: a possible biomarker of seasonal affective disorder. Psychiatry Res 2011; 187:370-4. [PMID: 20832867 DOI: 10.1016/j.psychres.2010.08.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 08/09/2010] [Accepted: 08/12/2010] [Indexed: 10/19/2022]
Abstract
Our goal was to challenge both normal controls and patients with seasonal affective disorders (SAD) to various light histories and then measure their retinal response modulation using the electroretinogram (ERG) in both winter and summer. In winter and summer, 11 normal controls and 12 SAD patients were exposed to three different light conditions for 1 h (10,000, 100 and 5 lux) followed by an ERG. Groups showed similar ERG amplitudes in the 100 lux condition. Compared with the 100-lux condition, in controls, the ERG response was significantly increased in the 5-lux condition; in SAD, it was significantly decreased in the 10,000-lux condition. This pattern was present in both seasons. This is the first time a retinal response modulation anomaly has been observed in SAD patients in both the depressed and euthymic states. Retinal response modulation may represent an interesting biomarker of the disease for future research.
Collapse
Affiliation(s)
- Anne-Marie Gagné
- Research Center University Laval Robert-Giffard, Québec, QC, Canada
| | | |
Collapse
|
9
|
Fountoulakis KN, Fotiou F, Iacovides A, Kaprinis G. Is there a dysfunction in the visual system of depressed patients? Ann Gen Psychiatry 2005; 4:7. [PMID: 15845143 PMCID: PMC1088013 DOI: 10.1186/1744-859x-4-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Accepted: 03/29/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND: The aim of the current study was to identify a possible locus of dysfunction in the visual system of depressed patients. MATERIALS AND METHODS: Fifty Major Depressive patients aged 21-60 years and 15 age-matched controls took part in the study The diagnosis was obtained with the SCAN v 2.0. The psychometric assessment included the HDRS, the HAS, the Newcastle Scales, the Diagnostic Melancholia Scale and the GAF scale. Flash Electroretinogram and Electrooculogram were performed in all subjects. The statistical analysis included ANCOVA, Student's t-test and Pearson Product Moment Correlation Coefficient were used. RESULTS: The Electro-oculographic findings suggested that all subtypes of depressed patients had lower dark trough and light peak values in comparison to controls (p < 0.001), while Arden ratios were within normal range. Electroretinographic recordings did not reveal any differences between patients and controls or between subtypes of depression. DISCUSSION: The findings of the current study provide empirical data in order to assist in the understanding of the international literature and to explain the mechanism of action of therapies like sleep deprivation and light therapy.
Collapse
Affiliation(s)
| | - Fotis Fotiou
- Laboratory of Clinical Neurophysiology, 1Department of Neurology, Aristotle University of Thesssaloniki, Greece
| | - Apostolos Iacovides
- Laboratory of Psychophysiology, 3Department of Psychiatry, Aristotle University of Thesssaloniki, Greece
| | - George Kaprinis
- Laboratory of Psychophysiology, 3Department of Psychiatry, Aristotle University of Thesssaloniki, Greece
| |
Collapse
|
10
|
Hébert M, Beattie CW, Tam EM, Yatham LN, Lam RW. Electroretinography in patients with winter seasonal affective disorder. Psychiatry Res 2004; 127:27-34. [PMID: 15261702 DOI: 10.1016/j.psychres.2004.03.006] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2003] [Revised: 01/04/2004] [Accepted: 03/17/2004] [Indexed: 11/22/2022]
Abstract
A retinal sensitivity abnormality has been hypothesized in seasonal affective disorder (SAD). To explore this hypothesis, the electroretinogram (ERG) was used to assess retinal sensitivity at the level of the rod photoreceptor system. We examined 27 depressed patients who met DSM-III-R criteria for major depression, recurrent, with a seasonal (winter) pattern and 23 normal control subjects who were age-paired and sex-matched as much as possible with the SAD patients. ERG testing was performed in dark-adapted, dilated eyes in winter between 10:00 and 15:00 h. Retinal sensitivity was based on the light stimulus intensity necessary to reach a 50-microV amplitude threshold. We found that retinal sensitivity was significantly lower (0.21 log units) in SAD patients compared with normal control subjects and that 55% of the patients had a retinal sensitivity value one standard deviation lower than the mean value of the control subjects. These results are consistent with a retinal hyposensitivity hypothesis for SAD, but the explanation for lower rod photoreceptor sensitivity in SAD is not known. We hypothesize that brain neurotransmitter dysregulation may be at the origin of both the mood disorder and retinal sensitivity change.
Collapse
Affiliation(s)
- Marc Hébert
- Department of Ophthalmology, Laval University Medical Research Center CHUQ, Faculty of Medicine, Laval University, Sainte-Foy, Quebec, Canada
| | | | | | | | | |
Collapse
|
11
|
Szabó Z, Antal A, Tokaji Z, Kálmán J, Kéri S, Benedek G, Janka Z. Light therapy increases visual contrast sensitivity in seasonal affective disorder. Psychiatry Res 2004; 126:15-21. [PMID: 15081623 DOI: 10.1016/j.psychres.2003.12.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2003] [Revised: 09/06/2003] [Accepted: 12/18/2003] [Indexed: 11/24/2022]
Abstract
The purpose of this study was to investigate the effects of light therapy on visual contrast sensitivity in patients with seasonal affective disorder (n=10) and healthy control subjects (n=10). Static and dynamic visual contrast sensitivity was measured using a Venus system before and after 4 weeks of light therapy (10,000 lux, 30 min, 5 times a week). Light therapy increased static visual contrast sensitivity in the patients. We found no significant difference between the patients and controls either before or after light therapy. These results raise the possibility that light therapy induces retinal sensitization in seasonal affective disorder.
Collapse
Affiliation(s)
- Zoltán Szabó
- Department of Psychiatry, Albert Szent-Györgyi Center for Medical and Pharmaceutical Sciences, Faculty of Medicine, University of Szeged, Semmelweis u.6, H-6725 Szeged, Hungary.
| | | | | | | | | | | | | |
Collapse
|
12
|
Cermakian N, Boivin DB. A molecular perspective of human circadian rhythm disorders. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2003; 42:204-20. [PMID: 12791440 DOI: 10.1016/s0165-0173(03)00171-1] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A large number of physiological variables display 24-h or circadian rhythms. Genes dedicated to the generation and regulation of physiological circadian rhythms have now been identified in several species, including humans. These clock genes are involved in transcriptional regulatory feedback loops. The mutation of these genes in animals leads to abnormal rhythms or even to arrhythmicity in constant conditions. In this view, and given the similarities between the circadian system of humans and rodents, it is expected that mutations of clock genes in humans may give rise to health problems, in particular sleep and mood disorders. Here we first review the present knowledge of molecular mechanisms underlying circadian rhythmicity, and we then revisit human circadian rhythm syndromes in light of the molecular data.
Collapse
Affiliation(s)
- Nicolas Cermakian
- Douglas Hospital Research Center, McGill University, 6875 LaSalle boulevard, Quebec H4H 1R3, Montreal, Canada
| | | |
Collapse
|
13
|
Abstract
Seasonal Affective Disorder (SAD) is a condition of regularly occurring depressions in winter with a remission the following spring or summer. In addition to depressed mood, the patients tend to experience increased appetite and an increased duration of sleep during the winter. SAD is a relatively common condition, affecting 1-3% of adults in temperate climates, and it is more prevalent in women. The pathological mechanisms underlying SAD are incompletely understood. Certain neurotransmitters have been implicated; a dysfunction in the serotonin system in particular has been demonstrated by a variety of approaches. The role of circadian rhythms in SAD needs to be clarified. The phase-delay hypothesis holds that SAD patients' circadian rhythms are delayed relative to the sleep/wake or rest/activity cycle. This hypothesis predicts that the symptoms of SAD will improve if the circadian rhythms can be phase-advanced. There is some experimental support for this. SAD can be treated successfully with light therapy. In classical light therapy, the SAD sufferer sits in front of a light box, exposed to 2000-10,000 lux for 30-120 min daily during the winter. Other forms of light treatments, pharmacotherapy, and other therapies are currently being tested for SAD.
Collapse
Affiliation(s)
- Andres Magnusson
- Department of Psychiatry, Ullevaal University Hospital, Oslo, Norway.
| | | |
Collapse
|
14
|
Hébert M, Dumont M, Lachapelle P. Electrophysiological evidence suggesting a seasonal modulation of retinal sensitivity in subsyndromal winter depression. J Affect Disord 2002; 68:191-202. [PMID: 12063147 DOI: 10.1016/s0165-0327(00)00192-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
BACKGROUND An anomaly in the retinal adaptation processes to the decreased light exposure in winter has been suggested as a contributing factor in winter depression. The purpose of this study was to investigate seasonal variations in rod sensitivity in normal subjects and in subjects with seasonal mood variations. METHODS Nine normal subjects (5 men, 4 women, aged 21-28 years) and 12 subjects with subsyndromal seasonal affective disorder (S-SAD)(3 men, 9 women, aged 21-44 years) were selected based on their global seasonality score (GSS) from the Seasonal Pattern Assessment Questionnaire. Scotopic electroretinograms (ERGs) were obtained once in winter and once in summer. Retinal sensitivity, which represents a relative threshold, was obtained from the rod ERG luminance-response functions. RESULTS A difference in retinal sensitivity between the two groups appeared only in the winter with lower retinal sensitivity found in the S-SAD group. A positive correlation between the GSS and the magnitude of the winter decrease in rod sensitivity was also observed. LIMITATIONS The S-SAD subjects studied in this research did not receive a formal psychiatric evaluation. This will be necessary in future studies to determine if the changes in retinal sensitivity are specific to seasonal affective disorders. In addition, in the present study, the differences in age and gender between the two groups limit the interpretation of the possible contribution of these two parameters to the results. CONCLUSION The seasonal changes in retinal sensitivity that parallel seasonal mood variations suggest that the ERG may represent a useful tool to investigate seasonal affective disorders.
Collapse
Affiliation(s)
- Marc Hébert
- Department of Ophthalmology, McGill University-Montreal Children's Hospital Research Institute, Montreal, Quebec, Canada.
| | | | | |
Collapse
|
15
|
Abstract
Circadian rhythms in the retina may reflect intrinsic rhythms in the eye. Previous reports on circadian variability in electrophysiological human retinal measures have been scanty, and the results have been somewhat inconsistent. We studied the circadian variation of the electrooculography (EOG), electroretinography (ERG), and visual threshold (VTH) in subjects undergoing a 36h testing period. We used an ultrashort sleep-wake cycle to balance effects of sleep and light-dark across circadian cycles. Twelve healthy volunteers (10 males, 2 females; mean age 26.3 years, standard deviation [SD] 8.0 years, range 19-40 years) participated in the study. The retinal functions and oral temperature were measured every 90 min. The EOG was measured in the light, whereas the ERG and the VTH were measured in the dark. Sleep was inferred from activity detected by an Actillume monitor. The EOG peak-to-peak responses followed a circadian rhythm, with the peak occurring late in the morning (acrophase 12:22). The ERG b-wave implicit time peaked in the early morning (acrophase 06:46). No statistically significant circadian rhythms could be demonstrated in the ERG a-wave implicit time or peak-to-peak amplitude. The VTH rhythm peaked in the early morning (acrophases 07:59 for blue and 07:32 for red stimuli). All retinal rhythms showed less-consistent acrophases than the temperature and sleep rhythms. This study demonstrated several different circadian rhythms in retinal electrophysiological and psychophysical measures of healthy subjects. As the retinal rhythms had much poorer signal-to-noise ratios than the temperature rhythm, these measures cannot be recommended as circadian markers.
Collapse
Affiliation(s)
- A Tuunainen
- Department of Psychiatry, University of California San Diego, La Jolla 92093-0667, USA
| | | | | | | |
Collapse
|
16
|
Terman JS, Terman M. Photopic and scotopic light detection in patients with seasonal affective disorder and control subjects. Biol Psychiatry 1999; 46:1642-8. [PMID: 10624545 DOI: 10.1016/s0006-3223(99)00221-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Retinal sensitivity may play a role in the pathogenesis of seasonal affective disorder (SAD) and response to light therapy. METHODS Using a dark adaptation procedure, SAD patients and normal control subjects were tested in the winter and summer, with patients retested after light treatment. The eyes were preadapted to bright light followed by 30 min in darkness, during which subjects detected a dim signal titrated around the detection threshold. Photopic (cone-mediated) and scotopic (rod-mediated) components of the data were identified by nonlinear exponential curve fits to successive threshold estimates. RESULTS Patients (n = 24) showed significantly lower cone and rod thresholds in the summer than winter, while control subjects (n = 12) showed a similar trend. Relative to the control subjects, however, patients were supersensitive in winter (lower cone final threshold, faster rod recovery). Clinical responders to morning light showed a small summer-like increase in cone sensitivity, whereas nonresponders became subsensitive. In comparison to darker-eyed patients, blue-eyed patients showed a larger summertime increase in cone sensitivity and a similar trend after response to morning light. CONCLUSIONS Heightened retinal sensitivity with increased light exposure, and supersensitivity of patients relative to control subjects in winter, may play roles in the pathogenesis of winter depression and the action of therapeutic light.
Collapse
Affiliation(s)
- J S Terman
- New York State Psychiatric Institute 10032, USA
| | | |
Collapse
|
17
|
Graw P, Recker S, Sand L, Kräuchi K, Wirz-Justice A. Winter and summer outdoor light exposure in women with and without seasonal affective disorder. J Affect Disord 1999; 56:163-9. [PMID: 10701473 DOI: 10.1016/s0165-0327(99)00037-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
BACKGROUND The annual decrease of daylight duration initiates a depressive phase in patients with seasonal affective disorder (SAD), and light therapy treats it. How much bright light exposure in winter and summer these patients actually receive may help understand the pathogenetic factors initiating SAD. METHODS During a week in winter and summer, women with and without SAD kept daily logs of the time spent outdoors, subjective sleep, and self-ratings of mood and alertness. RESULTS Compared with the winter depressive state, mood, alertness, and sleep of SAD patients improved in summer to control values, but did not correlate with the amount of light exposure. In summer, patients with SAD spent more time outdoors than controls. LIMITATION Light logs--in comparison with light monitor measurements--may overestimate light exposure outdoors. CONCLUSION Women with SAD do not spend less time outdoors in winter than controls, but spend more time outdoors in summer. CLINICAL RELEVANCE Patients with SAD show a high amplitude seasonal difference in outdoor light exposure. The susceptibility to winter depression may arise not from behaviourally-related lack of sufficient light exposure, but an increased vulnerability to the amount of light received. They may require more light than controls to remain euthymic (higher light exposure in summer, light therapy in winter).
Collapse
Affiliation(s)
- P Graw
- Chronobiology and Sleep Laboratory, Psychiatric University Clinic, Basel, Switzerland
| | | | | | | | | |
Collapse
|
18
|
Abstract
Circadian pacemakers that drive rhythmicity in retinal function are found in both invertebrates and vertebrates. They have been localized to photoreceptors in molluscs, amphibians, and mammals. Like other circadian pacemakers, they entrain to light, oscillate based on a negative feedback between transcription and translation of clock genes, and control a variety of physiological and behavioral rhythms that often includes rhythmic melatonin production. As a highly organized and accessible tissue, the retina is particularly well suited for the study of the input-output pathways and the mechanism for rhythm generation. Impressive advances can now be expected as researchers apply new molecular techniques toward looking into the eye's clock.
Collapse
Affiliation(s)
- E D Herzog
- Department of Biology and NSF Center for Biological Timing, University of Virginia, Charlottesville 22903, USA.
| | | |
Collapse
|
19
|
Guillemette J, Hébert M, Paquet J, Dumont M. Natural bright light exposure in the summer and winter in subjects with and without complaints of seasonal mood variations. Biol Psychiatry 1998; 44:622-8. [PMID: 9787887 DOI: 10.1016/s0006-3223(97)00543-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Considering the success of bright light therapy in seasonal affective disorders, it was suggested that seasonal mood disorders are triggered by decreased exposure to bright light in the winter; however, no previous studies have used objective measures to assess seasonal patterns of bright light illumination in subjects with seasonal mood variations. METHODS Eleven subjects reporting seasonal mood variations and 8 control subjects had their levels of natural bright light (BL) exposure measured for 5-6 days with an ambulatory monitor during both the summer and winter, at a latitude of 45 degrees 31'N. RESULTS Both groups received significantly more BL in the summer than in the winter, but there was no difference between the two groups for the pattern of BL exposure, including total duration, daily distribution, and amplitude of seasonal variation. CONCLUSIONS These results suggest that complaints of seasonal mood variations are not caused by a differential pattern in bright light exposure compared to normals. It is possible, however, that some individuals are more sensitive than others to variations in natural bright light. Whether an increased vulnerability is due to a more fragile affective state or to a lower sensitivity to light remains to be determined.
Collapse
Affiliation(s)
- J Guillemette
- Laboratoire de chronobiologie, Hôpital du Sacré-Coeur de Montréal, Québec, Canada
| | | | | | | |
Collapse
|
20
|
Abstract
Despite the long history in medicine, the pathophysiological mechanism(s) of seasonal affective disorder (SAD) remain largely unknown. By employing a meta-analytic methodology, the authors of this study attempted to verify the validity of different pathophysiological mechanism(s) proposed for SAD. The findings showed that for phototherapy of medium light intensity, a combination of morning-evening therapy regime yielded the best therapeutic effect, and the antidepressant effect of the morning-evening light regime was superior to a single pulse of light administered at other times of day. Furthermore, the data showed that the antidepressant effect of a single pulse of light was similar for morning, midday, and evening light. These findings supported the photon-count hypothesis and refuted the proposed photoperiod, melatonin, and phase-shifting models of SAD.
Collapse
Affiliation(s)
- T M Lee
- Department of Psychology, University of Hong Kong, Hong Kong.
| | | | | | | | | |
Collapse
|
21
|
Jinks RN, White RH, Chamberlain SC. Dawn, diacylglycerol, calcium, and protein kinase C--the retinal wrecking crew. A signal transduction cascade for rhabdom shedding in the Limulus eye. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1996; 35:45-52. [PMID: 8823934 DOI: 10.1016/1011-1344(96)07307-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Vertebrate and invertebrate photoreceptors shed their photosensitive membrane on a daily basis. Although we have detailed knowledge of the morphology of the disc shedding and renewal process in vertebrate photoreceptors, and of the turnover of rhabdom in invertebrate photoreceptors, we know relatively little about the molecular mechanisms whereby these processes are triggered by light and/or by circadian efferent input to the retina. We have used the horseshoe crab, Limulus polyphemus, as a model system to unravel the molecular means by which the trigger light is communicated to the intracellular machinery responsible for the daily breakdown of the photosensitive membrane. Phorbol esters, potent and specific activators of protein kinase C (PKC), induce a robust burst of rhabdom shedding when injected subretinally into the compound lateral eye of Limulus. This occurs in the absence of the light trigger normally required to initiate shedding in the lateral eye at dawn, suggesting that PKC may play a role in the light triggering of rhabdom shedding. Diacylglycerol (DAG) analogs were also found to elicit rhabdom shedding in the lateral eye without a light trigger, but at uncharacteristically high concentrations. However, injecting inositol trisphosphate (InsP3) and DAG analog simultaneously results in a tenfold decrease in the concentration of DAG analog required to initiate a shedding event. Immunohistochemical screening for PKC in the lateral eye shows that two isozymes (PKC beta II and PKC zeta) are co-localized to the retinular cell rhabdom. Taken together, these data suggest that light triggers rhabdom shedding at dawn via a classical Ca(2+)-sensitive PKC, similar to PKC beta II, which is activated synergistically by the light-evoked production of DAG and InsP3.
Collapse
Affiliation(s)
- R N Jinks
- Institute for Sensory Research, Syracuse University, NY 13244-5290, USA
| | | | | |
Collapse
|
22
|
Ozaki N, Rosenthal NE, Myers F, Schwartz PJ, Oren DA. Effects of season on electro-oculographic ratio in winter seasonal affective disorder. Psychiatry Res 1995; 59:151-5. [PMID: 8771230 DOI: 10.1016/0165-1781(95)02788-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Low electro-oculographic (EOG) ratios have been reported in patients with seasonal affective disorder (SAD) during the winter. This study evaluated the effects of the changing seasons on EOG ratios in SAD patients. Sixteen outpatients with SAD and 16 age-, sex-, and medication-matched normal volunteers had EOG testing during the winter and again during the summer. There was a significant season x group interaction in EOG ratios, with normal subjects showing higher ratios in winter than in summer--a seasonal variation not observed in SAD patients. SAD patients may have a subsensitivity to environmental light that leads them to experience symptoms during the winter.
Collapse
Affiliation(s)
- N Ozaki
- Clinical Psychobiology Branch, National Institute of Mental Health, Bethesda, MD 20892, USA
| | | | | | | | | |
Collapse
|
23
|
Meesters Y, Jansen JH, Beersma DG, Bouhuys AL, van den Hoofdakker RH. Light therapy for seasonal affective disorder. The effects of timing. Br J Psychiatry 1995; 166:607-12. [PMID: 7620745 DOI: 10.1192/bjp.166.5.607] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Sixty-eight patients with seasonal affective disorder participated in a 10,000-lux light treatment study in which two questions were addressed: do response rates differ when the light is applied at different times of the day and does short-term rank ordering of morning and evening light influence response rates? METHOD Three groups of patients received a 4-day light treatment: (I) in the morning (8.00-8.30 a.m., n = 14), (II) in the afternoon (1.00-1.30 p.m., n = 15) or (III) in the evening (8.00-8.30 p.m., n = 12). Two additional groups of patients received two days of morning light treatment followed by two days of evening light (IV, n = 13) or vice versa (V, n = 14). RESULTS Response rates for groups I, II and III were 69, 57 and 80% respectively, with no significant differences between them. Response rates for groups IV and V were 67 and 50% respectively; this difference was not significant and these percentages did not differ significantly from those of groups I and III. CONCLUSIONS The results indicate that the timing of light treatment is not critical and that short-term rank ordering of morning and evening light does not influence therapeutic outcome.
Collapse
Affiliation(s)
- Y Meesters
- Academic Hospital Groningen, The Netherlands
| | | | | | | | | |
Collapse
|
24
|
Abstract
The authors claim psychiatric mental health nurses, particularly those in private practice, must recognize symptom patterns of Seasonal Affective Disorder (SAD) so that appropriate treatment, including holistic modalities, can be instigated. Using a case study presentation, the authors describe the disorder and atypical phototherapy treatment.
Collapse
|
25
|
Arbisi PA, Depue RA, Krauss S, Spoont MR, Leon A, Ainsworth B, Muir R. Heat-loss response to a thermal challenge in seasonal affective disorder. Psychiatry Res 1994; 52:199-214. [PMID: 7972575 DOI: 10.1016/0165-1781(94)90088-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This study extends earlier findings of poorly facilitated postexercise heat loss during the winter in seasonal affective disorder (SAD). While depressed in the winter, 19 SAD subjects exhibited a significantly impaired postexercise heat loss relative to 10 control subjects. During the summer while euthymic, SAD subjects did not significantly differ from control subjects in postexercise heat loss. Since thermoregulatory heat loss is a highly dopamine-dependent process, these results support earlier findings of poorly facilitated dopamine availability in SAD during the winter and suggest a centrally mediated effect of light in SAD.
Collapse
Affiliation(s)
- P A Arbisi
- Department of Psychology, University of Minnesota, Minneapolis
| | | | | | | | | | | | | |
Collapse
|
26
|
Partonen T, Partinen M. Light treatment for seasonal affective disorder: theoretical considerations and clinical implications. Acta Psychiatr Scand Suppl 1994; 377:41-5. [PMID: 8053365 DOI: 10.1111/j.1600-0447.1994.tb05801.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The concept of seasonal affective disorder (SAD) includes any depression whose onset is related to a certain season. Reduced environmental light is hypothesized to be the main precipitating factor of winter depression. Light treatment is used to prevent the onset of depressive episodes and to reduce depressive symptoms in patients with depression during winter months. The mechanisms of action which lead to the well-documented antidepressant response are still unknown. Several hypotheses of the pathogenesis of SAD are discussed, and the clinical practice of light treatment is reviewed.
Collapse
Affiliation(s)
- T Partonen
- Ullanlinna Sleep Disorders Clinic and Research Centre, Helsinki, Finland
| | | |
Collapse
|
27
|
Ozaki N, Rosenthal NE, Moul DE, Schwartz PJ, Oren DA. Effects of phototherapy on electrooculographic ratio in winter seasonal affective disorder. Psychiatry Res 1993; 49:99-107. [PMID: 8153191 DOI: 10.1016/0165-1781(93)90098-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Low electrooculographic (EOG) ratios have been reported in patients with seasonal affective disorder (SAD). This study was undertaken to replicate these results and to consider the effects of light therapy on the EOG in SAD patients. Sixteen outpatients with SAD and 16 age-, sex-, and medication-matched control subjects had EOG testing before and after 1 week of light therapy during the winter. The EOG ratios in the SAD patients were only marginally lower than those in the normal control subjects. These differences persisted after light therapy. Although the slightly decreased EOG ratios in SAD patients might have resulted from an artifact of test variability, drowsiness, or other confounding factors, the difference between patients and control subjects raises the possibility of retinal abnormality in SAD.
Collapse
Affiliation(s)
- N Ozaki
- Clinical Psychobiology Branch, National Institute of Mental Health, Bethesda, MD 20892
| | | | | | | | | |
Collapse
|
28
|
Danilenko KV, Putilov AA. Diurnal and seasonal variations in cortisol, prolactin, TSH and thyroid hormones in women with and without seasonal affective disorder. ACTA ACUST UNITED AC 1993. [DOI: 10.1080/09291019309360211] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
29
|
Oren DA, Moul DE, Schwartz PJ, Alexander JR, Yatnada EM, Rosenthal NE. An investigation of ophthalmic function in winter seasonal affective disorder. ACTA ACUST UNITED AC 1993. [DOI: 10.1002/depr.3050010107] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
30
|
Humpel C, Neudorfer C, Philipp W, Steiner HJ, Haring C, Schmid KW, Schwitzer J, Saria A. Effects of bright artificial light on monoamines and neuropeptides in eight different brain regions compared in a pigmented and nonpigmented rat strain. J Neurosci Res 1992; 32:605-12. [PMID: 1527805 DOI: 10.1002/jnr.490320416] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Seasonal affective disorder is a form of depression which recurs at the same time of the year. Exposure to bright artificial light at a dose of 2,500 lux is used to treat seasonal affective disorders. We exposed a pigmented (Brown Norway) and a nonpigmented (Sprague-Dawley) rat strain with bright artificial light for 21 days at two doses (2,500 and 6,100 lux) and analyzed dopamine, dihydroxyphenyl-acetic acid, 5-hydroxytryptamine (5-HT), and 5-hydroxyindole-acetic acid (5-HIAA) by high performance liquid chromatography (HPLC) and electrochemical detection in eight different brain regions. Furthermore, we measured tissue levels of substance P (SP), neurokinins (NK), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), and neuropeptide Y (NPY) with radioimmunoassay. Our data obtained with light microscopy show that bright artificial light at both doses induced a massive destruction of photoreceptors in the retina of albino rats but not of the pigmented rat strain. Retinal lesion of photoreceptors resulted in increased tissue levels of all measured neuropeptides except SP in the hypothalamus and increased VIP in the ventral tegmental area/substantia nigra. Furthermore, increased 5-HT and 5-HIAA tissue levels were found in the ventral tegmental area/substantia nigra. In contrast, in the frontal cortex there was a significant reduction in 5-HIAA tissue levels and a decreased 5-HIAA/5-HT ratio, indicating decreased 5-HT metabolism. Light exposure of the pigmented rat strain revealed no changes in the measured biogenic amines and neuropeptides in any investigated brain region. Our data suggest that retinal lesion but not direct visual neurotransmission induced changes in neurotransmitters in some brain regions. We conclude that Brown Norway rats but not Sprague-Dawley rats are useful to study neurochemical effects of bright artificial light. However, Sprague-Dawley rats may be a useful tool to study biochemical mechanisms of photoreceptor damage by bright light.
Collapse
Affiliation(s)
- C Humpel
- Neurochemical Unit, University Hospital of Psychiatry, University of Innsbruck, Austria
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Abstract
Retinal mechanisms have been hypothesized in the pathophysiology of seasonal affective disorder (SAD). Electroretinography (ERG) is a noninvasive electrophysiologic test that provides an objective measure of photoreceptor and retinal function. We conducted dark-adapted ERG examinations with a bright white light stimulus in a group of depressed, drug-free patients with seasonal affective disorder (6 men, 18 women) diagnosed by DSM-III-R criteria, and a group of sex- and age-matched control subjects (6 men, 16 women) during the winter. A significant difference was found between SAD patients and controls, but female SAD patients had lower ERG b-wave amplitudes than female controls, while male SAD patients had higher amplitudes than the matched controls. The ERG b-wave implicit times (times from onset of stimulus to peak of b-wave) were significantly longer in the left eyes of the male control subjects. These data may indicate subtle retinal changes in patients with SAD, but the results must be considered preliminary because of the small number of subjects studied and the large intersubject variability in the ERG procedure.
Collapse
Affiliation(s)
- R W Lam
- Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | | | | | | |
Collapse
|
32
|
Oren DA, Joseph-Vanderpool JR, Rosenthal NE. Adaptation to dim light in depressed patients with seasonal affective disorder. Psychiatry Res 1991; 36:187-93. [PMID: 2017533 DOI: 10.1016/0165-1781(91)90130-h] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Supersensitivity to light has been suggested as a possible trait marker for manic-depressive illness. Because winter seasonal affective disorder (SAD) is associated with depressive episodes during dark winter days, the authors postulated that SAD patients would show diminished sensitivity to dim light. Dark-adaptation curves were obtained in 10 medication-free, depressed SAD patients and in 10 age- and sex-matched drug-free healthy controls. Contrary to the hypothesis, patients adapted to dim light more rapidly than controls.
Collapse
Affiliation(s)
- D A Oren
- Section on Environmental Psychiatry, National Institute of Mental Health, Bethesda, MD 20892
| | | | | |
Collapse
|