Morning or evening bright light treatment of winter depression? The significance of hypersomnia

Comparative study of sleep and circadian rhythms in patients presenting unipolar or bipolar major depressive episodes

Currently, there is a major challenge in distinguishing between unipolar and bipolar major depressive episode. A significant body of research has been dedicated to identifying biomarkers that can aid in this differentiation due to its crucial implications, particularly for therapeutic and prognostic purposes. Among the biomarkers of interest, markers related to sleep and circadian rhythms show promise and could potentially aid in making this distinction. Nevertheless, no study has simultaneously examined sleep-wake disorders, circadian rhythms, and seasonal patterns using both subjective and objective measures. This study aims to characterize and compare the sleep-wake and rhythm disorders including patients with unipolar major depressive episode (n = 72) and with bipolar major depressive episode (n = 43) using both subjective markers (using self-report questionnaires and sleep complaints) and objective markers (using actigraphy). Patients with unipolar major depressive episode seem to experience significantly poorer quality of sleep, more symptoms of insomnia and lower sleep efficiency compared to patients with bipolar major depressive episode. On the other hand, patients with bipolar major depressive episode exhibit significantly more symptoms of motor retardation and hypersomnia compared to patients with unipolar disorder. These results hold significant implications for identifying individuals with unipolar major depressive episode or bipolar major depressive episode using sleep and circadian markers, and for developing recommended and personalized therapeutic strategies.

Hypersomnolence, Hypersomnia, and Mood Disorders

Relationships between symptoms of hypersomnolence, psychiatric disorders, and hypersomnia disorders (i.e., narcolepsy and idiopathic hypersomnia) are complex and multidirectional. Hypersomnolence is a common complaint across mood disorders; however, patients suffering from mood disorders and hypersomnolence rarely have objective daytime sleepiness, as assessed by the current gold standard test, the Multiple Sleep Latency Test. An iatrogenic origin of symptoms of hypersomnolence, and sleep apnea syndrome must be considered in a population of psychiatric patients, often overweight and treated with sedative drugs. On the other hand, psychiatric comorbidities, especially depression symptoms, are often reported in patients with hypersomnia disorders, and an endogenous origin cannot be ruled out. A great challenge for sleep specialists and psychiatrists is to differentiate psychiatric hypersomnolence and a central hypersomnia disorder with comorbid psychiatric symptoms. The current diagnostic tools seem to be limited in that condition, and further research in that field is warranted.

Utilization of Diurnal Rodents in the Research of Depression

Preclinical Research Most neuropsychiatric research, including that related to the circadian system, is performed using nocturnal animals, mainly laboratory mice and rats. Mood disorders are known to be associated with circadian rhythm abnormalities, but the mechanisms by which circadian rhythm disruptions interact with depression remain unclear. As the circadian system of diurnal and nocturnal mammals differs, we previously suggested that the utilization of diurnal animal models may be advantageous for understanding these relations. During the last 10 years, we and others established the validity of several diurnal rodent species as a model for the interactions between circadian rhythms and depression. Diurnal rodents respond to photoperiod manipulation in a similar way to humans, the behavioral outcome is directly related to the circadian system, and treatment that is effective in patients is also effective in the model. Moreover, less effective treatments in patients are also less effective in the model. We, therefore, suggest that using diurnal animal models to study circadian rhythms-related affective disorders, such as depression, will provide new insights that will hopefully lead to the development of more effective treatments. Drug Dev Res 77 : 347-356, 2016. © 2016 Wiley Periodicals, Inc.

Hypersomnia subtypes, sleep and relapse in bipolar disorder

BACKGROUND

Though poorly defined, hypersomnia is associated with negative health outcomes and new-onset and recurrence of psychiatric illness. Lack of definition impedes generalizability across studies. The present research clarifies hypersomnia diagnoses in bipolar disorder by exploring possible subgroups and their relationship to prospective sleep data and relapse into mood episodes.

METHOD

A community sample of 159 adults (aged 18-70 years) with bipolar spectrum diagnoses, euthymic at study entry, was included. Self-report inventories and clinician-administered interviews determined features of hypersomnia. Participants completed sleep diaries and wore wrist actigraphs at home to obtain prospective sleep data. Approximately 7 months later, psychiatric status was reassessed. Factor analysis and latent profile analysis explored empirical groupings within hypersomnia diagnoses.

RESULTS

Factor analyses confirmed two separate subtypes of hypersomnia ('long sleep' and 'excessive sleepiness') that were uncorrelated. Latent profile analyses suggested a four-class solution, with 'long sleep' and 'excessive sleepiness' again representing two separate classes. Prospective sleep data suggested that the sleep of 'long sleepers' is characterized by a long time in bed, not long sleep duration. Longitudinal assessment suggested that 'excessive sleepiness' at baseline predicted mania/hypomania relapse.

CONCLUSIONS

This study is the largest of hypersomnia to include objective sleep measurement, and refines our understanding of classification, characterization and associated morbidity. Hypersomnia appears to be comprised of two separate subgroups: long sleep and excessive sleepiness. Long sleep is characterized primarily by long bedrest duration. Excessive sleepiness is not associated with longer sleep or bedrest, but predicts relapse to mania/hypomania. Understanding these entities has important research and treatment implications.

Photoperiodic and circadian bifurcation theories of depression and mania

Seasonal effects on mood have been observed throughout much of human history.  Seasonal changes in animals and plants are largely mediated through the changing photoperiod (i.e., the photophase or duration of daylight).  We review that in mammals, daylight specifically regulates SCN (suprachiasmatic nucleus) circadian organization and its control of melatonin secretion.  The timing of melatonin secretion interacts with gene transcription in the pituitary pars tuberalis to modulate production of TSH (thyrotropin), hypothalamic T3 (triiodothyronine), and tuberalin peptides which modulate pituitary production of regulatory gonadotropins and other hormones.  Pituitary hormones largely mediate seasonal physiologic and behavioral variations.  As a result of long winter nights or inadequate illumination, we propose that delayed morning offset of nocturnal melatonin secretion, suppressing pars tuberalis function, could be the main cause for winter depression and even cause depressions at other times of year.  Irregularities of circadian sleep timing and thyroid homeostasis contribute to depression.  Bright light and sleep restriction are antidepressant and conversely, sometimes trigger mania.  We propose that internal desynchronization or bifurcation of SCN circadian rhythms may underlie rapid-cycling manic-depressive disorders and perhaps most mania.  Much further research will be needed to add substance to these theories.

Basic sleep and circadian science as building blocks for behavioral interventions: a translational approach for mood disorders

Sleep and circadian functioning has been of particular interest to researchers focused on improving treatments for psychiatric illness. The goal of the present paper is to highlight the exciting research that utilizes basic sleep and circadian science as building blocks for intervention in the mood disorders. The reviewed evidence suggests that the sleep and circadian systems are a) disrupted in the mood disorders and linked to symptoms, b) open systems that can be modified, c) the focus of interventions which have been developed to effectively treat sleep disturbance within mood disorders, and d) intimately linked with mood, such that improvements in sleep are associated with improvements in mood. Although significant positive treatment effects are evident, more research is needed to fill the gap in our basic understanding of the relationship between sleep and mood.

Hypersomnia and depressive symptoms: methodological and clinical aspects

The associations between depressive symptoms and hypersomnia are complex and often bidirectional. Of the many disorders associated with excessive sleepiness in the general population, the most frequent are mental health disorders, particularly depression. However, most mood disorder studies addressing hypersomnia have assessed daytime sleepiness using a single response, neglecting critical and clinically relevant information about symptom severity, duration and nighttime sleep quality. Only a few studies have used objective tools such as polysomnography to directly measure both daytime and nighttime sleep propensity in depression with normal mean sleep latency and sleep duration. Hypersomnia in mood disorders, rather than a medical condition per se, is more a subjective sleep complaint than an objective finding. Mood symptoms have also been frequently reported in hypersomnia disorders of central origin, especially in narcolepsy. Hypocretin deficiency could be a contributing factor in this condition. Further interventional studies are needed to explore whether management of sleep complaints improves mood symptoms in hypersomnia disorders and, conversely, whether management of mood complaints improves sleep symptoms in mood disorders.

Bright light treatment as add-on therapy for depression in 28 adolescents: a randomized trial

BACKGROUND

In the last decade, a significant incidence of depression in the younger population has been observed. Bright light therapy, an effective therapeutic option for depressed adults, could also provide safe, economical, and effective rapid recovery in adolescents.

METHOD

The randomized trial included 28 inpatients (18 females and 10 males) between 14 and 17 years old with depressive complaints. The study was conducted between February and December of 2010 in Rodewisch, Germany. Half of the patients (n = 14) first received placebo (50 lux) 1 hour a day in the morning from 9:00 am to 10:00 am for 1 week and then received bright light therapy (2,500 lux) for 1 week in the morning from 9:00 am to 10:00 am. The other half (n = 14) first received bright light therapy and then received placebo. Patients were encouraged to continue ongoing treatment (fluoxetine 20 mg/day and 2 sessions of psychotherapy/week) because there were no changes in medication/dosage and psychotherapy since 1 month before the 4-week study period. For assessment of depressive symptoms, the Beck Depression Inventory (BDI) was administered 1 week before and 1 day before placebo treatment, on the day between placebo and bright light treatment, and on the day after and 1 week after bright light treatment. Saliva samples of melatonin and cortisol were collected at 8:00 am and 8:00 pm 1 week before and 1 day before placebo treatment, on the day between placebo and bright light treatment, on the day after bright light treatment, and 1 week after bright light treatment and were assayed for melatonin and cortisol to observe any change in circadian timing.

RESULTS

The BDI scores improved significantly (P = .015). The assays of saliva showed significant differences between treatment and placebo for evening melatonin (P = .040). No significant adverse reactions were observed.

CONCLUSIONS

Antidepressant response to bright light treatment in this age group was statistically superior to placebo.

TRIAL REGISTRATION

World Health Organization International Clinical Trials Registry Platform identifier: DRKS00003309.

Winter Depression: Integrating mood, circadian rhythms, and the sleep/wake and light/dark cycles into a bio-psycho-social-environmental model

The phase shift hypothesis (PSH) states that most patients with SAD become depressed in the winter because of a delay in circadian rhythms with respect to the sleep/wake cycle: According to the PSH, these patients should preferentially respond to the antidepressant effects of bright light exposure when it is scheduled in the morning so as to provide a corrective phase advance and restore optimum alignment between the circadian rhythms tightly coupled to the endogenous circadian pacemaker and those rhythms that are related to the sleep/wake cycle. Recent support for the PSH has come from studies in which symptom severity was shown to correlate with the degree of circadian misalignment: it appears that a subgroup of patients are phase advanced, not phase delayed; however, the phase-delayed type is predominant in SAD and perhaps in other disorders as well, such as non-seasonal unipolar depression. It is expected that during the next few years the PSH will be tested in these and other conditions, particularly since healthy subjects appear to have more severe symptoms of sub-clinical dysphoria correlating with phase-delayed circadian misalignment; critically important will be the undertaking of treatment trials to investigate the therapeutic efficacy of morning bright light or afternoon/evening low-dose melatonin in these disorders in which symptoms are more severe as the dim light melatonin onset (DLMO) is delayed with respect to the sleep/wake cycle (non-restorative sleep should also be evaluated, as well as bipolar disorder). The possibility that some individuals (and disorders) will be of the phase-advanced type should be considered, taking into account that the correct timing of phase-resetting agents for them will be bright light scheduled in the evening and/or low-dose melatonin taken in the morning. While sleep researchers and clinicians are accustomed to phase-typing patients with circadian-rhythm sleep disorders according to the timing of sleep, phase typing based on the DLMO with respect to the sleep/wake cycle may lead to quite different recommendations for the optimal scheduling of phase-resetting agents, particularly for the above disorders and conditions.

Bright light treatment of depression for older adults [ISRCTN55452501]

BACKGROUND

The incidence of insomnia and depression in the elder population is significant. It is hoped that use of light treatment for this group could provide safe, economic, and effective rapid recovery.

METHODS

In this home-based trial we treated depressed elderly subjects with bright white (8,500 Lux) and dim red (<10 Lux) light for one hour a day at three different times (morning, mid-wake and evening). A placebo response washout was used for the first week. Wake treatment was conducted prior to the initiation of treatment, to explore antidepressant response and the interaction with light treatment. Urine and saliva samples were collected during a 24-hour period both before and after treatment and assayed for aMT6s and melatonin respectively to observe any change in circadian timing. Subjects wore a wrist monitor to record light exposure and wrist activity. Daily log sheets and weekly mood (GDS) and physical symptom (SAFTEE) scales were administered. Each subject was given a SCID interview and each completed a mood questionnaire (SIGH-SAD-SR) before and after treatment. Also, Hamilton Depression Rating (SIGH-SAD version) interviews were conducted by a researcher who was blind to the treatment condition. A control group of healthy, age-matched, volunteers was studied for one day to obtain baseline data for comparison of actigraphy and hormone levels.

RESULTS

Eighty-one volunteers, between 60 and 79 years old, completed the study. Both treatment and placebo groups experienced mood improvement. Average GDS scores improved 5 points, the Hamilton Depression Rating Scale (HDRS) 17 scores (extracted from the self-rated SIGH-SAD-SR) improved 6 points. There were no significant treatment effects or time-by-treatment interactions. No significant adverse reactions were observed in either treatment group. The assays of urine and saliva showed no significant differences between the treatment and placebo groups. The healthy control group was active earlier and slept earlier but received less light than the depressed group at baseline.

CONCLUSION

Antidepressant response to bright light treatment in this age group was not statistically superior to placebo. Both treatment and placebo groups experienced a clinically significant overall improvement of 16%.

Seasonal affective disorder and its prevention by anticipatory treatment with bupropion XL

BACKGROUND

Seasonal affective disorder (SAD) can cause significant distress and impairment. No antidepressant studies have previously attempted to prevent the onset of autumn-winter depression.

METHODS

Three prospective, randomized, placebo-controlled prevention trials were conducted on 1042 SAD patients, enrolled in autumn and treated while still well, across the northern US and Canada. Patients received either bupropion XL 150-300 mg or placebo daily by mouth from enrollment until spring and were then followed off medications for 8 additional weeks. Primary efficacy variables were end-of-treatment depression-free rates and survival distributions of depressive recurrence.

RESULTS

Despite a reported average of 13 previous seasonal depressive episodes, almost 60% of patients had never previously been treated for depression. Major depression recurrence rates during the three studies for bupropion XL and placebo groups were 19% versus 30% (p = 0.026), 13% versus 21% (p = 0.049), and 16% versus 31%; yielding a relative risk reduction across the three studies of 44% for patients taking bupropion XL. Survival analyses for depression onset also favored bupropion XL over placebo (p = .081, .057, and <.001).

CONCLUSIONS

It is possible to prevent recurrence of seasonal major depressive episodes by beginning bupropion treatment early in the season while patients are still well.

Effects of light therapy on sleep, mood, and temperature in women with nonseasonal major depression

Research has supported the applicability and efficacy of light therapy in the treatment of nonseasonal depression. The investigators examined the effects of light therapy on sleep, core temperature, depressed mood, and perception of fatigue and energy in a sample of pre-menopausal and post-menopausal women diagnosed with nonseasonal, nonbipolar depression. Women were randomly assigned to either light therapy (n = 16) or placebo (n = 13) for a 28-day period. Pre and post measures of sleep and core temperature were collected. In addition, measures of depressed mood, fatigue, and energy were collected throughout the study period. Significant changes in depression and energy were found in the treatment group, but not in the placebo group. There was a significant reduction in the temperature mesor and less wake time during the first third of the sleep period in the treatment group but not in the placebo group. Light therapy yielded significant improvement in depression when compared with placebo intervention and core temperature mesor returned to normal. There was no significant phase shift, perhaps due in part to the absence of any baseline circadian phase disturbances. Relationships between temperature, sleep, depressed mood, fatigue, and energy variables offer potential directions for future research and clinical intervention.

Light treatment of mood disorders

In 1981, seven patients with nonseasonal depression were treated with bright white light in 1982, bright artificial light was used to treat a manic-depressive patient with a seasonal mood cycle. In the last 20 years, a plethora of studies have further defined the depressive populations, who are responsive to light treatment; the optimal timing, intensity, spectral frequency, and duration of treatment; its comparison with other pharmacological interventions; predictors of response; side-effect profiles; viable placebo-control conditions; alternative devices and forms of administration; potential mechanisms and anatomical pathways mediating light's physiological effects; and its application to other disorders and subsyndromaI states. These studies have been conducted across multiple countries with surprisingly consistent results. Further work is needed, as highlighted in this review, to clarify the specific mechanism of action in subtypes of depressive disorders and differential age and gender effects. Although the majority of work in this area is relatively new, it behooves the reader to remember that Solomon, almost 3000 years ago, wrote in Ecclesiastes: "Truly the light is sweet and a pleasant thing it is for the eyes to behold the sun" (11:7).

Dawn simulation and bright light in the treatment of SAD: a controlled study

BACKGROUND

Some small controlled studies have found that dawn simulation is effective in treating seasonal affective disorder (SAD). With a larger sample size and a longer duration of treatment, we compared dawn simulation with bright light therapy and a placebo condition in patients with SAD.

METHOD

Medication-free patients with SAD were randomly assigned to one of three conditions: bright light therapy (10,000 lux for 30 min, from 6:00 AM to 6:30 AM), dawn simulation (1.5 hour dawn signal from 4:30 AM to 6:00 AM peaking at 250 lux), and a placebo condition, a dim red light (1.5 hour dawn signal from 4:30 am to 6:00 AM peaking at 0.5 lux.) Over the subsequent 6 weeks, the subjects were blindly rated by a psychiatrist using the Structured Interview Guide for the Hamilton Depression Rating-Seasonal Affective Disorder Version (SIGH-SAD). We modeled the profiles of the remissions (SIGH-SAD < or = 8) and response (> or =50% decrease in SIGH-SAD) to treatment over time using Cox proportional hazards models.

RESULTS

The sample consisted of 95 subjects who were randomized to the three conditions: bright light (n = 33), dawn simulation (n = 31) and placebo (n = 31). Dawn simulation was associated with greater remission (p <.05) and response (p <.001) rates compared to the placebo. Bright light did not differ significantly from the placebo. Dawn simulation was associated with greater remission (p <.01) and response (p <.001) rates compared to the bright light therapy. The mean daily hours of sunshine during the week before each visit were associated with a significant increase in likelihood of both remission (p <.001) and response (p <.001).

CONCLUSIONS

Dawn simulation was associated with greater remission and response rates compared to the placebo and compared to bright light therapy. The hours of sunshine during the week before each assessment were associated with a positive clinical response.

Bright light therapy of subsyndromal seasonal affective disorder in the workplace: morning vs. afternoon exposure

OBJECTIVE

Bright light therapy in seasonal affective disorder (SAD) has been studied extensively. However, little attention has been given to subsyndromal seasonal affective disorder (SSAD) or the use of bright light in the workplace. Many patients using bright light boxes complain of the inconvenience of use. Much of this inconvenience involves the often-recommended early timing of the bright light therapy. Patients, who already have difficulty awakening, often have difficulty using the bright light therapy soon after awakening before going to work. If bright light could be used effectively in the workplace, the treatment would be more convenient; the improved convenience would probably improve compliance. In this study, we studied the effectiveness of bright light therapy in subjects with SSAD in the workplace, comparing morning bright light with afternoon bright light.

METHOD

Morning and afternoon bright light treatment (2500 lux) were compared in 30 subsyndromal seasonal affective disorder patients using the bright light therapy in the workplace. Hamilton Depression Ratings and subjective measures of mood, energy, alertness and productivity were assessed before and after 2 weeks of light therapy.

RESULTS

Both morning and evening bright light significantly decreased the depression ratings and improved the subjective mood, energy, alertness and productivity scores. However, there were no significant differences between the two times of administration of the bright light treatment. Both bright light treatments were well tolerated.

CONCLUSION

Bright light given in the workplace improves subjective ratings of mood, energy, alertness and productivity in SSAD subjects. Morning and afternoon bright lights resulted in similar levels of improvement.

Owls, larks and the significance of morningness/eveningness rhythm propensity in psychiatric-mental health nursing

In the last decade there has been an upsurge in the research focusing on the interplay between the human circadian timing system and behavioral patterns in health and illness. Of particular interest in this area of inquiry is the overlay of what has been termed chronotype. What this refers to is the propensity of biological rhythms to express themselves in certain patterns of behavior. Commonly, these patterns have received names such as owl (evening chronotype) or lark (morning chronotype). Many people are neither a strong morning nor evening chronotype. If illness represents a change in the way a person's body functions within a given environment, then it is reasonable to believe that an "owl's" symptom presentation may vary significantly from the patterns of a "lark" who becomes ill. Recognizing that psychiatric nurses at both the generalist and the advanced practice levels have a strong interest in patterns of behavior, it stands to reason that using a lens that incorporates notions of the body's clock becomes essential. The interplay between the body's timing system and the thousands of other psychobiological rhythmic functions occurring everyday and within every human being is referred to as chronobiology. This article provides a primer for psychiatric nurses on issues of chronobiology related to morningness and eveningness rhythm propensity.

Dose-response relationship of phototherapy for seasonal affective disorder: a meta-analysis

OBJECTIVE

The therapeutic effect of phototherapy for seasonal affective disorder (SAD) has been widely investigated. However, the antidepressant effect of various light intensities is inconclusive. The purpose of this study was to evaluate the dose-response relationship of phototherapy for SAD.

METHOD

A meta-analytical methodology was applied to 39 studies of phototherapy for SAD. The studies collected were screened for study quality by a threats-to-validity method before inclusion. The fixed-effects-model analysis of variance procedures were used for data analysis.

RESULTS

The results indicated that different light intensities produced different effects in reducing the typical symptoms, as measured by the Hamilton Depression Rating Scale, of patients with SAD. However, no significant differences in these effects were revealed between strong, medium and dim light in reducing the atypical symptoms of patients.

CONCLUSION

These findings showed that light intensity varied positively with the antidepressant effect for typical but not for atypical symptoms of SAD, suggesting that light intensity tended to have different therapeutic effects on the typical and atypical symptoms of SAD.

Melatonin treatment of winter depression: a pilot study

Five patients with winter depression received low doses of melatonin in the afternoon, and five patients received placebo capsules. Melatonin treatment significantly decreased depression ratings compared to placebo. If these findings are replicated in a larger sample with documentation of expected phase shifts, the phase shift hypothesis will be substantially supported.

Pathophysiological mechanism of seasonal affective disorder

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.

Circadian temperature and cortisol rhythms during a constant routine are phase-delayed in hypersomnic winter depression

Circadian temperature, cortisol, and thyroid-stimulating hormone (TSH) rhythms during a constant routine were assessed in 6 female controls and 6 female patients with hypersomnic winter depression (seasonal affective disorder, SAD) before and after morning bright light treatment. After sleep was standardized for 6 days, the subjects were sleep-deprived and at bed rest for 27 hours while rectal temperature, cortisol, and TSH levels were assessed. The minimum of the fitted rectal temperature rhythm was phase-delayed in the SAD group compared to the controls 5:42 AM vs. 3:16 AM (p < .005); with bright light treatment, the minimum advanced from 5:42 AM to 3:36 AM (p = .06). The minimum of the cortisol rhythm was phase-delayed in the SAD group compared to the control group, 12:11 AM vs. 10:03 PM (P < .05); with bright light treatment, the minimum advanced from 12:11 AM to 10:38 PM (P = .06) [corrected]. The acrophase of the TSH rhythm was not significantly phase-delayed in SAD subjects compared to control, though the trend appeared to be toward a phase-delay (p = .07). After bright light therapy, the TSH acrophase was not significantly different in the SAD subjects; the trend was a phase-advance (p = .09). Overall, the data suggest that circadian rhythms are phase-delayed relative to sleep in SAD patients and that morning bright light phase-advances those rhythms.

Treatment of seasonal affective disorder: a review

OBJECTIVE

To review the status of current treatment of seasonal affective disorder (SAD).

METHOD

Treatment studies of SAD published between January 1989 and March 1995 were identified using a computerized MEDLINE literature search. Additional citations were obtained from the reference sections of these articles. Studies included in this review were selected using operational methodologic criteria.

RESULTS

Many studies support the efficacy of bright light therapy using a fluorescent light box. The best studied protocol is > 2500 lux white light for 2 hours per day, but newer protocols using 10,000 lux for 30 minutes have comparable response rates. Studies of light visors and other head-mounted devices also report similar response rates, but have not yet shown superiority over putative control conditions. There are fewer medication studies in SAD, but controlled studies suggest that fluoxetine, d-fenfluramine and propranolol are effective. Other treatments such as dawn simulation require further study. No studies of psychological treatments for SAD were found. Many studies had methodologic limitations, including brief treatment periods, small sample sizes, and lack of replication, that limit the generalizability of findings.

CONCLUSION

There are several well-studied, effective treatments for SAD, including light therapy and medications. However, further research must be done to demonstrate sustained treatment response over time, to clarify the intensity-response relationship of light therapy, to clarify the role of light therapy and medications, and to assess combination treatments.

Clinical and chronobiological effects of light therapy on nonseasonal affective disorders

Light therapy (bright or dim light) was given at different times (morning or evening) to 27 unmedicated patients with nonseasonal depression (according to DSM-III-R criteria) and 16 normal volunteers. Circadian rhythms in body temperature were measured before and after light therapy. Bright light significantly improved clinical symptoms of depression, as measured by the Hamilton Rating Scale for Depression (HRSD), independent of the time of phototherapy. Dim light therapy had no effect on HRSD scores. Circadian rhythms of body temperatures in patients with affective disorder were more sensitive to the entraining effects of bright light than those of normal subjects, but these effects were not related to clinical improvement. Bright light exposure has an antidepressant effect on patients with nonseasonal depression, but the effect is unlikely to be mediated via the same circadian system that regulates body temperature.

Light treatment for sleep disorders: consensus report. IV. Sleep phase and duration disturbances

Advanced and delayed sleep phase disorders, and the hypersomnia that can accompany winter depression, have been treated successfully by appropriately timed artificial bright light exposure. Under entrainment to the 24-h day-night cycle, the sleep-wake pattern may assume various phase relationships to the circadian pacemaker, as indexed, for example, by abnormally long or short intervals between the onset of melatonin production or the core body temperature minimum and wake-up time. Advanced and delayed sleep phase syndromes and non-24-h sleep-wake syndrome have been variously ascribed to abnormal intrinsic circadian periodicity, deficiency of the entrainment mechanism, or--most simply--patterns of daily light exposure insufficient for adequate phase resetting. The timing of sleep is influenced by underlying circadian phase, but psychosocial constraints also play a major role. Exposure to light early or late in the subjective night has been used therapeutically to produce corrective phase delays or advances, respectively, in both the sleep pattern and circadian rhythms. Supplemental light exposure in fall and winter can reduce the hypersomnia of winter depression, although the therapeutic effect may be less dependent on timing.

Light treatment in seasonal and nonseasonal depression

Ninety patients with major depressive disorder were classified according to seasonal (n = 68, 50 women) or nonseasonal (n = 22, 17 women) pattern according to DSM-III-R. They were also clinically evaluated and rated before and after morning (0600-0800) or evening (1800-2000) light treatment for 10 days in a room with a luminance of 350 cd/m2 (approximately 1500 lx) at eye level. Mood ratings were performed using both the Comprehensive Psychopathological Rating Scale and the Hamilton Depression Rating Scale. Depressed patients with seasonal pattern improved significantly more than those with a nonseasonal pattern suggesting a specific nonplacebo effect of light treatment in depressed patients with seasonal pattern. There were no significant differences in outcome when light treatment was given in the morning or in the evening, and not between patients with and without atypical symptoms such as carbohydrate craving or increased appetite.

Light therapy for seasonal affective disorder. The effects of timing

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.

Dawn simulation compared with a dim red signal in the treatment of winter depression

In a randomized, parallel design, 19 patients with winter depression were treated with either a week of a white 1.5-hr dawn simulation peaking at 250 lux or a week of a red, 1.5-hr dawn signal peaking at 2 lux. The subjects were told that they would receive either a white or red dawn reaching in intensity that would be dimmer than standard bright light treatment. At the end of both the baseline week and the treatment week subjects were blindly assessed with the Hamilton Rating Scale for Depression (HDRS). Analysis of covariance was used to compare the two dawn treatments. The white, 1.5-hr, 250 lux dawn simulation resulted in significantly (p < 0.05) lower HDRS scores compared to the red, 1.5-hr, 2 lux dawn. This is the second controlled study which indicates that dawn simulation is an effective treatment for winter depression.

Morning light therapy for winter depression: predictors of response

Bright-light therapy is widely regarded as an effective treatment for winter seasonal affective disorder (SAD). We attempted to identify predictors of light therapy response in 54 depressed, drug-free outpatients diagnosed with SAD by DSM-III-R criteria. After a baseline week, patients were treated for 2 weeks with 2500-lx cool-white fluorescent light exposure from 0600 to 0800 daily. The results showed that light therapy significantly reduced depression scores. Several indices of atypical and typical symptoms correlated with response, but none was clearly superior to the pre-treatment depression score. A multiple regression analysis identified 3 factors (hypersomnia, increased eating and younger age) that predicted light-therapy response. These results suggest that specific symptoms of hypersomnia and hyperphagia are predictors of response to morning bright-light therapy in SAD.

Effects of morning light treatment on subjective sleepiness and mood in winter depression

The effects of morning light treatment on mood, subjective sleepiness and body temperature were investigated with 13 outpatients with winter depression and 13 healthy controls. Bright light for 1 h daily for 2 weeks resulted in a significant reduction in depression ratings and evening subjective sleepiness in the patients compared with the healthy controls. Even a short 15-min exposure to light daily produced these changes.

Effects of morning light treatment on subjective sleepiness and mood in winter depression

The effects of morning light treatment on mood, subjective sleepiness and body temperature were investigated with 13 outpatients with winter depression and 13 healthy controls. Bright light for 1 h daily for 2 weeks resulted in a significant reduction in depression ratings and evening subjective sleepiness in the patients compared with the healthy controls. Even a short 15-min exposure to light daily produced these changes.

Dim light melatonin onset and circadian temperature during a constant routine in hypersomnic winter depression

The onset of melatonin secretion under dim light conditions (DLMO) and the circadian temperature rhythm during a constant routine were assessed in 6 female controls and 6 female patients with winter depression (seasonal affective disorder, SAD) before and after bright light treatment. After sleep was standardized for 6 days, the subjects were sleep-deprived and at bedrest for 27 h while core temperature and evening melatonin levels were determined. The DLMO of the SAD patients was phase-delayed compared with controls (2310 vs 2138); with bright light treatment, the DLMO advanced (2310 to 2135). The minimum of the fitted rectal temperature rhythm was phase-delayed in the SAD group compared with the controls (0542 vs 0316); with bright light treatment, the minimum advanced (0542 vs 0336).

Morning and evening light treatment of seasonal affective disorder: response, relapse and prediction

Patients with seasonal affective disorder were randomly assigned to treatment with light in the morning (9.00-12.00 a.m.; n = 16; ML) or evening (6.00-9.00 p.m.; n = 11; EL). An intensive 24-day assessment procedure revealed the same response rates: 57% for ML, 50% for EL. During the rest of the winter season a relatively low relapse rate of 54% was found. No differences between ML and EL were found in the time course of depressed mood or fatigue. A significant negative correlation was found between diurnal variation during baseline and therapeutic response: the larger the diurnal variation the less the response, indicating a potential negative predictive value for this symptom. There were no significant correlations between baseline fatigue or hypersomnia and response.

Parental reports of seasonal mood and behavior changes in children

OBJECTIVE

The chief purpose of this study was to investigate the nature and prevalence of children's seasonal symptoms.

METHOD

Parental reports of seasonal changes in six mood or behavioral symptoms (sleeping, eating, irritability, energy, withdrawal, and sadness) were surveyed for children living across the United States. The sample included 892 girls (mean age = 10.5 +/- 1.0 years) and 788 boys (mean age = 10.6 +/- 0.9 years), with a response rate of 46% for girls' parents and 39% for boys' parents.

RESULTS

At least one winter recurring symptom was reported in 48.5% of children, as compared with 9.1% in fall and 10.8% in spring. Winter symptoms were reported equally in girls and boys with one exception ("is tired"); age effects were found for three symptoms only in girls ("sleep more," "is tired," and "withdraws"). Regional effects showed more winter symptoms reports in northern zones than in southern zones.

CONCLUSIONS

Given the potential therapeutic benefit of light therapy in children with such seasonal patterns, careful assessment of seasonality is merited for children with winter mood and behavior problems.

High intake of sweets late in the day predicts a rapid and persistent response to light therapy in winter depression

Demographic characteristics, depression ratings, and detailed daily records of symptoms were examined as possible predictors of the response to light therapy of 51 patients with seasonal affective disorder. Of 26 items, high intake (> 1 portion) of sweets in the second half of the day was the best predictor of a rapid and persistent response to light therapy. The intake of sweets may either act on similar neurochemical substrates to those affected by light or provide a behavioral marker for individuals susceptible to light response.

Biogenic amines in seasonal affective disorder: effects of light therapy

Wintertime measures of central and peripheral monoamine neurotransmitter system activity in 17 medication-free depressed patients with seasonal affective disorder (SAD) were compared with those in eight healthy volunteers. Mean cerebrospinal fluid (CSF) concentrations of the principal metabolites of norepinephrine (NE), serotonin, and dopamine did not differ between the two groups, nor did mean basal or orthostatically stimulated plasma NE levels. Patients' pretreatment depression ratings were inversely correlated with resting plasma NE concentrations. Fourteen SAD patients were clear responders to 2 weeks of full-spectrum bright light treatment. Neither the transmitter measures nor their interrelatedness was affected significantly by phototherapy.

Serotonin, carbohydrates, and atypical depression

At least three categories of atypical depression have been described. The hysteroid dysphoria is characterized by repeated episodes of depressed mood in response to feeling rejected, and a craving for sweets and chocolate. Two other issues are characterized by a cyclical occurrence of changes of mood and appetite, i.e., the late luteal phase dysphoric disorder (DSM-III-R, appendix), or "the premenstrual syndrome" (PMS), and the major depression with seasonal pattern (DSM-III-R), or seasonal affective disorder (SAD). The reactive mood changes are frequently accompanied by features as hypersomnia, lethargy and increased appetite, particularly with a preference for carbohydrates. Central serotonin pathways participate in the regulation of mood and behavioural impulsivity, and modulate eating patterns qualitatively and quantitatively. Depressives with PMS og SAD benefit, in general, from treatments with serotonin potentiating drugs, suggesting that brain serotonin plays a role in the pathophysiology. Ingestion of carbohydrates increases the plasma ratio of tryptophan to other large neutral amino acids in man and animal, and the serotonin synthesis in the rat brain. Based on these findings it has been suggested that the excessive carbohydrate intake by patients with PMS and SAD reflects a self-medication that temporarily relieves the vegetative symptoms via an increased central serotonergic activity.

Contrasts between symptoms of summer depression and winter depression

Epidemiological studies and studies of clinical populations suggest that there are primarily two opposite patterns of seasonally recurring depressions: summer depression and winter depression. In addition, there is preliminary evidence that the two seasonal types of depression may have opposite types of vegetative symptoms. In the present study, we prospectively monitored symptoms of depression in 30 patients with recurrent summer depression and 30 sex-matched patients with recurrent winter depression and compared the symptom profiles of the two groups. Consistent with predictions based on the earlier reports, we found that winter depressives were more likely to have atypical vegetative symptoms, with increased appetite, carbohydrate craving, weight gain and hypersomnia, and that summer depressives were more likely to have endogenous vegetative symptoms, with decreased appetite and insomnia. A cluster analysis performed on the patients' symptom profiles without reference to season of occurrence of their episodes separated 78% of the summer depressives and winter depressives from each other on the basis of their symptoms (chi 2 = 19.29, P less than 0.001).