Light treatment in seasonal and nonseasonal depression

A 6-day combined wake and light therapy trial for unipolar depression

BACKGROUND

There are a dozen studies on double or triple chronotherapy in depression (sleep deprivation [wake therapy] + light therapy + sleep advance/stabilization). We investigated efficacy and feasibility of a modified triple chronotherapy protocol.

METHODS

Thirty-five hospitalized patients with moderately severe non-seasonal depressive disorder, mostly free from antidepressants, underwent a 6-day protocol consisting of partial sleep deprivation late in the second half of the night (from 4:00 to 8:00) in a light therapy room (blue-enhanced white light increased hourly from 600→1300→2200→2800 lx) alternating with recovery nights with morning light treatment from 7:00 to 8:00. Patients were randomized to wear glasses with no filter (clear, N = 19) or filtering blue wavelength (orange-appearance, light intensity diminution by ∼70%, N = 16) during the treatments. Sleep was targeted to be shifted at least 1 h earlier. Depression was scored using HDRS-17 (Hamilton Depression Rating Scale) and BDI-II (Beck Depression Inventory-II) - before and after the 6-days treatment, HDRS-6-SR - daily, and visual analogue scales (VAS) for mood and energy - several times every day.

RESULTS

Depression levels significantly declined following the first night and after 6-days treatment, with no difference between white and orange lights. Nevertheless, some superiority of white light emerged with respect to response rate (mood VAS), immediate effect during the 4-h treatment sessions (energy VAS), and expected treatment outcomes. All patients successfully advanced bedtime/wake-up (by 30-40 minutes) and resisted naps during daytime.

LIMITATIONS

Relatively small sample size.

CONCLUSIONS

The modified triple chronotherapy was well tolerated and improved depression. Light spectrum/intensity plays some role in the response.

Moderators of Cognitive Therapy and Bright Light Therapy Effects on Depressive Symptoms in Patients with Breast Cancer

BACKGROUND

Cognitive therapy (CT) and bright light therapy (BLT) have been found to be effective to treat depressive symptoms in breast cancer patients. No study has investigated the baseline patients' characteristics that are associated with better outcomes with CT vs. BLT in this population. This study aimed to assess, in breast cancer patients, the moderating role of eight clinical variables on the effects of CT and BLT on depressive symptoms.

METHODS

This is a secondary analysis of a randomized controlled trial conducted in 59 women who received an 8-week CT or BLT and completed questionnaires evaluating depression and possible moderating variables.

RESULTS

Patients benefited more from BLT when they had no prior history of major depressive disorder, higher depression scores on the Hospital Anxiety and Depression Scale (HADS-D) at baseline, a greater initial preference for BLT, and when they received BLT during spring or summer. Patients benefited more from CT when they had a lower initial preference for receiving CT, higher depression scores on the HADS-D, and seasonal depressive symptoms.

CONCLUSIONS

Although replication is needed, findings of this study suggest the existence of different profiles of patients more likely to benefit from CT and BLT.

TRIAL REGISTRATION

NCT01637103 https://clinicaltrials.gov/ct2/show/NCT01637103.

Rate of switch from bipolar depression into mania after morning light therapy: A historical review

Light therapy (LT) is efficacious for bipolar depression with effect sizes equivalent to those in antidepressant pharmacotherapy trials. Patients with bipolar disorder (BD) show a 15-40% rate of manic switches during antidepressant drug treatment. The rate of manic switches during LT has never been estimated. We searched all the literature studies reporting effects of antidepressant LT in BD. 41 studies described 799 patients with BD treated with antidepressant LT, from among which 7 (0.9%) switched into mania and 11 (1.4%) switched into hypomania. The method of assessment of treatment-emergent symptoms significantly influenced the detection of switches into mania: 0% when no method was reported, 0.8% with clinical mental state examination, and 3% with rating scales (χ² = 14.805, d.f. 4, p = 0.005). The rate of switch increased to 18.8% when considering the 16 patients with rapid-cycling BD. Switches occurred independent of treatment modality (light intensity, duration, and circadian timing of administration). The available literature shows that the highest reported rate of switch from bipolar depression into mania after LT is closely similar to the 4% switch rate expected during the placebo treatment of BD, thus not justifying specific concerns when using this treatment option.

Patients' Experience of Winter Depression and Light Room Treatment

Background. There is a need for more knowledge on the effects of light room treatment in patients with seasonal affective disorder and to explore patients' subjective experience of the disease and the treatment. Methods. This was a descriptive and explorative study applying qualitative content analysis. A purposeful sample of 18 psychiatric outpatients with a major depressive disorder with a seasonal pattern and a pretreatment score ≥12 on the 9-item Montgomery-Åsberg Depression self-rating scale was included (10 women and 8 men, aged 24-65 years). All patients had completed light room treatment (≥7/10 consecutive weekdays). Data was collected two weeks after treatment using a semistructured interview guide. Results. Patients described a clear seasonal pattern and a profound struggle to adapt to seasonal changes during the winter, including deterioration in sleep, daily rhythms, energy level, mood, activity, and cognitive functioning. Everyday life was affected with reduced work capacity, social withdrawal, and disturbed relations with family and friends. The light room treatment resulted in a radical and rapid improvement in all the major symptoms with only mild and transient side effects. Discussion. The results indicate that light room treatment is essential for some patients' ability to cope with seasonal affective disorder.

FORMAL AND MODEL DRIVEN DESIGN OF THE BRIGHT LIGHT THERAPY SYSTEM LUXAMET

Seasonal depression seriously diminishes the quality of life for many patients. To improve their condition, we propose LUXAMET, a bright light therapy system. This system has the potential to relieve patients from some of the symptoms caused by seasonal depression. The system was designed with a formal and model driven design methodology. This methodology enabled us to minimize systemic hazards, like blinding patients with an unhealthy dose of light. This was achieved by controlling race conditions and memory leaks, during design time. We prove that the system specification is deadlock as well as livelock free and there are no invariant violations. These proofs, together with the similarity between specification model and implementation code, make us confident that the implemented system is a reliable tool which can help patients during seasonal depression.

[The current state of research in bright light therapy]

The significance of light for the human organism and especially for the mental health is well-established for a long time. Therefore, the impact of light on mood and the use of bright light as a treatment-option for affective disorders have been studied extensively by scientists. Today bright light therapy is the treatment of choice for saisonal affective disorders. In the last years several clinical trials could demonstrate the therapeutic efficacy of bright light therapy for different neurological and psychiatric disorders such as sleep disorders, non-seasonal affective disorders or dementia. This article will give an overview about the neurobiological basis for light therapy and discuss different disorders responsive to light therapy. Finally a short overview about technical aspects of light therapy and new developments in light engineering will be presented.

Intensity and pleasantness of sucrose taste in patients with winter depression

OBJECTIVES

Increased consumption of carbohydrates and craving for sweets are considered core features of winter depression. Unfortunately, little is known about neural and behavioral correlates of these symptoms. The primary aim of the present study was to evaluate taste responses to sucrose solutions in depressed patients with seasonal affective disorder (SAD).

METHODS

Intensity and pleasantness ratings of sucrose solutions, electrogustometric thresholds, and taste identification abilities were assessed in depressed patients with SAD and non-seasonal affective disorder (non-SAD), and in non-depressed controls.

RESULTS

Electrogustometric thresholds and identification abilities did not differ between the study groups. There were no differences between the groups in intensity or pleasantness ratings of sucrose solutions (1-30%). The proportion of 'sweet likers', i.e. subjects rating the highest sucrose concentration as most pleasant, was similar in the controls, SAD, and non-SAD patients.

DISCUSSION

The present results suggest that: (i) winter depression is not associated with major alterations in gustatory function; and (ii) sweet craving and increased consumption of carbohydrates in patients with winter depression is not secondary to altered responses to sweet tastants. More studies are needed to characterize hedonic responses of patients with SAD to other sweet and non-sweet foods.

Clinical applications of melatonin in circadian disorders

Chronobiological disorders and syndromes include seasonal affective disorder (SAD), total blindness, advanced and delayed sleep phase syndrome, jet lag, and shift work maladaptation. These disorders are treated by adjusting circadian phase, using appropriately timed bright light exposure and melatonin administration (at doses of 0.5 mg or less). In some cases, it may be necessary to measure internal circadían phase, using the time when endogenous melatonin levels rise.

Improvement in Fatigue, Sleepiness, and Health-Related Quality of Life with Bright Light Treatment in Persons with Seasonal Affective Disorder and Subsyndromal SAD

Objective. To investigate the effects of bright light treatment for secondary outcome measures and to explore and validate empirically derived subgroups and treatment effects in subgroups. Methods. A descriptive design. A sample of forty-nine persons (mean age of 45.8) with clinically assessed seasonal affective disorder (SAD) or subsyndromal SAD (S-SAD) participated in a two-group clinical trial evaluating the effects of treatment with bright light therapy. A person-oriented cluster analysis was applied to study treatment effects in subgroups. Results. For the merged group, sleepiness (Epworth Sleepiness Scale), fatigue (fatigue questionnaire), and health-related quality of life (SF-36) were improved at posttreatment, and results were maintained at the one-month followup. Three distinct subgroups had a high level of fatigue in common, while the level of excessive daytime sleepiness and depressed mood differed between the subgroups. Over time, all subgroups improved following ten days treatment in a light room. Conclusion. Fatigue, excessive daytime sleepiness, and health-related quality of life improve in a similar way as depressed mood following treatment with bright light. The treatment was effective irrespective of the severity of the disorder, that is, for persons with SAD and subsyndromal SAD.

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.

Light room therapy effective in mild forms of seasonal affective disorder--a randomised controlled study

BACKGROUND

The most common way to provide bright light therapy to Swedish patients with Seasonal Affective Disorder (SAD), is treatment in a light therapy room. Since few studies have evaluated treatment provided in this setting and few have evaluated the effect of bright light in sub-clinical SAD (S-SAD), such a study including a one-month follow-up was designed.

METHODS

Fifty adults recruited from a previous prevalence study and clinically assessed as having SAD or S-SAD, were randomised to treatment in a light room or to a three-week waiting-list control group. The Hamilton Depression Rating Scale-Seasonal Affective Disorders Self-rating 29-items Version (SIGH-SAD/SR) was used to measure depressive mood at baseline, directly following treatment and at the one-month follow-up.

RESULTS

ANCOVA with adjustment for baseline depression score, showed a significant main effect for the light room therapy group (p<0.001). Fifty-four percent (n=13/24) improved > or = 50% while no such improvement was seen in the control condition (n=0/24). After merging the two groups, repeated measures ANOVA confirmed the experimental analysis (p<0.001). At the one-month follow-up, 83.0% (n=39/47) had improved > or = 50% and 63.8% (n=30/47) had normal depression scores, i.e. < or = 8.

CONCLUSIONS

Light room therapy was effective in reducing depressive symptoms in subjects with winter depressive mood. Results were maintained over a period of one month.

The circadian basis of winter depression

The following test of the circadian phase-shift hypothesis for patients with winter depression (seasonal affective disorder, or SAD) uses low-dose melatonin administration in the morning or afternoon/evening to induce phase delays or phase advances, respectively, without causing sleepiness. Correlations between depression ratings and circadian phase revealed a therapeutic window for optimal alignment of circadian rhythms that also appears to be useful for phase-typing SAD patients for the purpose of administering treatment at the correct time. These analyses also provide estimates of the circadian component of SAD that may apply to the antidepressant mechanism of action of appropriately timed bright light exposure, the treatment of choice. SAD may be the first psychiatric disorder in which a physiological marker correlates with symptom severity before, and in the course of, treatment in the same patients. The findings support the phase-shift hypothesis for SAD, as well as suggest a way to assess the circadian component of other psychiatric, sleep, and chronobiologic disorders.

Therapeutic mechanism in seasonal affective disorder: do fluoxetine and light operate through advancing circadian phase?

In the context of Lewy's phase delay hypothesis, the present study tested whether effective treatment of winter Seasonal Affective Disorder (SAD) is mediated by advancing of circadian phase. Following a baseline week, 78 outpatients with SAD were randomized into 8 weeks of treatment with either fluoxetine and placebo light treatment or light treatment and placebo pill. Depression levels were measured on the Ham17+7 and the BDI-II, and circadian phase was estimated on the basis of daily sleep logs and self-reported morningness-eveningness. Among the 61 outpatients with complete data, both treatments were associated with significant antidepressant effect and phase advance. However, pre- and post-treatment comparisons found that the degree of symptom change did not correlate with the degree of phase change associated with treatment. The study therefore provides no evidence that circadian phase advance mediates the therapeutic mechanism in patients with SAD. Findings are discussed in terms of the limitations of the circadian measures employed.

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%.

Association of morning illumination and window covering with mood and sleep among post-menopausal women

The antidepressant and sleep-promoting effects of light exposure might be useful for treating age-related mood and sleep disorders. In view of recent evidence suggesting beneficial effects of morning light, this study examined the associations of mood and sleep with morning light exposure, 24 h environmental illumination, and the degree to which the volunteers' bedroom windows were covered in the morning. We examined 459 postmenopausal women participating an ancillary study of the Women's Health Initiative conducted at the University of California, San Diego Clinical Center, San Diego, CA, USA. At baseline, volunteers completed a 4-week sleep-recall questionnaire. Volunteers were then assessed for 5-7 days in their home environments with actigraphic wrist monitors. During home recording, self-reported mood was assessed. Morning illumination during the first 4 h after arising, 24-h illumination mesor (cosine-fitted mean), and illumination acrophase (cosine-fitted peak time) were calculated. Sleep was scored each night using validated wrist actigraphic methods. A sleep diary was completed each morning. During two 24-h periods, urine was collected approximately every 2 h during wakefulness and following any voidings during the sleep period. Cosine-fitting established the acrophase of urinary 6-sulfatoxymelatonin (aMT6s) excretion. Morning illumination and 24-h illumination were modestly associated with better mood and sleep. Associations of light with mood and sleep were consistently greater for subjects whose body clocks were delayed relative to the group median. Less morning window covering in the subjects' bedrooms was associated with more morning light and less depressed mood. The results suggest that both morning and 24-h light exposure may be beneficial for older adults.

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).

Light therapy for non-seasonal depression

BACKGROUND

Efficacy of light therapy for non-seasonal depression has been studied without any consensus on its efficacy.

OBJECTIVES

To evaluate clinical effects of bright light therapy in comparison to the inactive placebo treatment for non-seasonal depression.

SEARCH STRATEGY

We searched the Depression Anxiety & Neurosis Controlled Trials register (CCDANCTR January 2003), comprising the results of searches of Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (1966 -), EMBASE (1980 -), CINAHL (1982 -), LILACS (1982 -), National Research Register, PsycINFO/PsycLIT (1974 -), PSYNDEX (1977 -), and SIGLE (1982 - ) using the group search strategy and the following terms: #30 = phototherapy or ("light therapy" or light-therapy). We also sought trials from conference proceedings and references of included papers, and contacted the first author of each study as well as leading researchers in the field.

SELECTION CRITERIA

Randomized controlled trials comparing bright light with inactive placebo treatments for non-seasonal depression.

DATA COLLECTION AND ANALYSIS

Data were extracted and quality assessment was made independently by two reviewers. The authors were contacted to obtain additional information.

MAIN RESULTS

Twenty studies (49 reports) were included in the review. Most of the studies applied bright light as adjunctive treatment to drug therapy, sleep deprivation, or both. In general, the quality of reporting was poor, and many reviews did not report adverse effects systematically. The treatment response in the bright light group was better than in the control treatment group, but did not reach statistical significance. The result was mainly based on studies of less than 8 days of treatment. The response to bright light was significantly better than to control treatment in high-quality studies (standardized mean difference (SMD) -0.90, 95% confidence interval (CI) -1.50 to -0.31), in studies applying morning light treatment (SMD -0.38, CI -0.62 to -0.14), and in sleep deprivation responders (SMD -1.02, CI -1.60 to -0.45). Hypomania was more common in the bright light group compared to the control treatment group (risk ratio 4.91, CI 1.66 to 14.46, number needed to harm 8, CI 5 to 20). Twenty studies (49 reports) were included in the review. Most of the studies applied bright light as adjunctive treatment to drug therapy, sleep deprivation, or both. Treatment

REVIEWERS' CONCLUSIONS

For patients suffering from non-seasonal depression, bright light therapy offers modest though promising antidepressive efficacy, especially when administered during the first week of treatment, in the morning, and as an adjunctive treatment to sleep deprivation responders. Hypomania as a potential adverse effect needs to be considered. Due to limited data and heterogeneity of studies these results need to be interpreted with caution.

Seasonal affective disorders: relevance of Icelandic and Icelandic-Canadian evidence to etiologic hypotheses

OBJECTIVE

This study tests the suggestion of earlier studies concerning the importance of genetic factors in the etiology of winter seasonal affective disorders (SADs) and subsyndromal winter SAD (S-SAD).

METHOD

Two study populations of Winnipeg, Manitoba residents were canvassed: 250 adults of wholly Icelandic descent and 1000 adults of non-Icelandic descent. We distributed the Seasonal Pattern Assessment Questionnaire by mail to these 2 populations, yielding 204 and 449 valid responses, respectively.

RESULTS

Rates of SAD and S-SAD proved markedly lower in the Icelandic population than those in the non-Icelandic population.

CONCLUSIONS

These differences seem unexplained by differences in ambient light or climate, thus indicating that genetic factors contribute to the expression of SADs. Compared with earlier findings from a group of adults of wholly Icelandic descent living in nearby rural Manitoba, the etiologic importance of as-yet-undetermined environmental factors unrelated to latitude or ambient light is also indicated.

Seasonal depression: the dual vulnerability hypothesis revisited

OBJECTIVE

In DSM-IV, winter seasonal affective disorder (SAD) is classified as a seasonal pattern of recurrent major depressive episodes in winter with full remission of symptoms in summer. However, other groups with "winter depression" have been identified, including patients with incomplete summer remission (ISR) and subsyndromal SAD (sub-SAD, winter depressive symptoms that do not meet criteria for major depression). In this study, we compare the clinical characteristics of these three seasonal groups and their response to light therapy.

METHOD

558 patients assessed at a specialized SAD Clinic were diagnosed using DSM-III-R or DSM-IV criteria. Clinical information was recorded using a checklist at index assessment. A subset of patients (N=192) were treated with an open, 2 week trial of light therapy using a 10000 lux fluorescent light box for 30 min per day in the early morning. Patients were assessed before and after treatment with the 29 item modified Hamilton Depression Rating Scale and clinical response was defined as greater than 50% improvement in scores.

RESULTS

The rates of some melancholic symptoms, anxiety, panic, suicidal ideation, and family history of mood disorder were lowest in the sub-SAD group. The clinical response rates to light therapy were highest in the sub-SAD group (N=32, 78%), intermediate in the SAD group (N=113, 66%), and lowest in the ISR group (N=47, 51%).

LIMITATIONS

This was a retrospective study of patients seen in a specialty clinic, although information was obtained in a standardized format. The light therapy trial had an open design so that placebo response could not be determined.

CONCLUSIONS

There are differences in both the patterns of clinical symptoms and the response to light therapy in these three groups with winter depression. These results are consistent with a dual vulnerability hypothesis that considers these groups to result from interaction of separate factors for seasonality and depression.

Sleep deprivation as a predictor of response to light therapy in major depression

BACKGROUND

While the majority of depressed patients benefit from total sleep deprivation (TSD), light therapy is regarded as a first-line treatment only for seasonal affective disorder (SAD). The results of light therapy in nonseasonal major depressive disorder have been non-conclusive. We examined the correlation of TSD response and light therapy response in major depressed patients.

METHODS

40 inpatients with major depressive disorder (seven with seasonal pattern, 33 without seasonal pattern) were deprived of a night's sleep. The TSD responders, as well as the TSD nonresponders, were randomly assigned to receive adjunct light therapy either with bright white light (2500 lux) or dim red light (50 lux) during 2 weeks beginning on the third day after TSD.

RESULTS

The 20 TSD responders improved significantly better under the light therapy than the 20 TSD nonresponders (according to the Hamilton Depression Rating Scale and the self-rating depression scale Bf-S; v. Zerssen).

LIMITATIONS

No significant difference could be found between the two light intensities. Since the patients were additionally treated with medication an interaction with the two adjunctive therapies cannot be excluded.

CONCLUSION

Our results indicate that a positive TSD response in major depressed patients can be predicative of beneficial outcome of subsequent light therapy.

Mood and energy regulation in seasonal and non-seasonal depression before and after midday treatment with physical exercise or bright light

The effects of two non-drug treatments (physical exercise and bright light) on mood, body weight and oxygen consumption were compared in age-matched groups of female subjects with winter depression, non-seasonal depression or without depression. It was found that oxygen consumption in the pre-treatment condition was similar in non-depressed subjects (n=18) and depressed non-seasonals (n=18), while comparatively lower values were obtained in winter depression (n=27). Neither mood nor metabolic parameters changed significantly in the group of nine untreated winter depressives. One week of physical exercise (1-h pedaling on a bicycle ergometer between 13.00 and 14.00 h) increased oxygen consumption in the group of nine winter depressives and lowered oxygen consumption in nine-subject groups of depressed and non-depressed non-seasonals. One week of bright light treatment (2-h exposure to 2500 lux between 14.00 and 16.00 h) increased oxygen consumption in nine winter depressives and nine non-depressed subjects, while no significant change in oxygen consumption was found in nine subjects with non-seasonal depression. Weight loss was observed in the groups treated with physical exercise and in the group of light-treated winter depressives. Winter depression responded equally well to exercising and light, while a significant therapeutic difference in favor of exercising was found in non-seasonal depression. Overall, the results of the study suggest that energy-regulating systems are implicated in the antidepressant action of the non-drug treatments.

Seasonal affective disorder

Seasonal affective disorder (SAD) is a form of recurrent depressive or bipolar disorder, with episodes that vary in severity. Seasonal patterns of depressive episodes are common, but SAD seems to be less common than such patterns suggest. SAD was at first believed to be related to abnormal melatonin metabolism, but later findings did not support this hypothesis. Studies of brain serotonin function support the hypothesis of disturbed activity. The short-allele polymorphism for serotonin transporter is more common in patients with SAD than in healthy people. Atypical depressive symptoms commonly precede impaired functioning, and somatic symptoms are frequently the presenting complaint at visits to family physicians. The best treatment regimens include 2500 Ix of artificial light exposure in the morning. When patients seem to have no response or to prefer another treatment, antidepressants should be considered.

Platelet serotonergic functions and light therapy in seasonal affective disorder

We investigated platelet 14C-serotonin uptake and platelet [3H]LSD and [3H]paroxetine binding in 11 patients with seasonal affective disorder (SAD). Patients were reinvestigated after light therapy, applied at 07.00-09.00 h for 10 consecutive days. The degree of depression was rated before and after light therapy using the Comprehensive Psychopathological Rating Scale (CPRS). Baseline data in patients were compared with data from a control group consisting of 11 age- and sex-matched healthy volunteers. Seven patients responded to light therapy with a > 50% reduction in CPRS scores. In non-responders, the reduction in CPRS was 24.7 +/- 5.5%. There was a significant inverse correlation (P = 0.014) between Km for platelet 14C-serotonin uptake and CPRS scores. Patients had significantly higher Bmax for platelet [3H]LSD binding (P = 0.04) and significantly lower Bmax for platelet [3H]paroxetine binding (P = 0.016). There was a strong, multiple correlation between Bmax for [3H]LSD, as the dependent variable, and Km, Vmax and Bmax for [3H]paroxetine binding in patients (P < 0.0001) but not in controls. Responders to light therapy had significantly higher Km (P = 0.023) and significantly lower Bmax for [3H]paroxetine binding (P = 0.028) than non-responders. Bmax for [3H]paroxetine binding increased significantly to normal levels after light therapy. The results indicate that SAD is associated with aberrations in the serotonin uptake mechanism. The enhanced 5-HT2-receptor density may reflect a consequential up-regulation.

Testing the hypothesis of a circadian phase disturbance underlying depressive mood in nonseasonal depression

In a crossover design, 8 nonseasonal depressed subjects, selected on the presence of diurnal mood variations, and 8 sex- and age-matched controls were exposed to dim light (< 10 lux) in the evening (18:00-21:00 h) and bright light (2500 lux) in the morning (ML, 6:00-9:00 h), to dim light in the morning and bright light in the evening (EL), or to dim light both in the evening and in the morning (DL) during 3 consecutive days in each of these conditions. There were no initial phase differences between depressed and healthy subjects in the timing of dim light melatonin onset, sleep termination, and body temperature. The phase shifts after EL and ML in both healthy and depressed subjects were as expected on the basis of a human phase response curve. On average, there was no therapeutic effect of the light exposure in the depressed patients. Two patients improved, but these effects do not seem to be related to shifts in the circadian system.

Cortisol in light treatment of seasonal and non-seasonal depression: relationship between melatonin and cortisol

The effect of bright light on cortisol and the relationship between melatonin and cortisol were studied in 63 depressed patients (42 patients with a seasonal pattern and 21 patients with a non-seasonal pattern). The patients were matched for age, time of treatment and severity of depression. Before and after light treatment the severity of the depression was rated with the Comprehensive Psychopathological Rating Scale (23 items) and the Hamilton Depression Rating scale (18 items), and serum cortisol and melatonin were drawn at nine time-points between 20.00 and 08.00 hours. Two hours of light treatment (350 cd m-2) was given daily for 10 days either in the morning (06.00-08.00 hours) or in the evening (18.00-20.00 hours). As reported earlier, patients with a seasonal pattern improved significantly more than patients with a non-seasonal pattern of depression, and no significant differences were found between the treatment efficacy of morning compared to evening light. A cosinor analysis showed that the cortisol batyphase was significantly advanced by morning light, but was not delayed by evening light. A delay in batyphase cortisol showed a weak significant correlation with a decrease in the absolute and relative sum of scores. The batyphase of cortisol occurred approximately 3 h earlier than the acrophase of melatonin. Of the changes in the melatonin acrophase 43% were reflected in a change of cortisol batyphase, indicating a hierarchical relationship with melatonin as the co-ordinating hormone transducing part of the information of the external light to the phase position of cortisol. No significant differences between patients with a seasonal or a non-seasonal pattern were seen in mesor, amplitude or batyphase of cortisol before treatment, and no significant changes in mesor or amplitude were seen as a result of light treatment.

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.

Will light brighten the future of the depressed patient?

The present explosive growth of interest in the therapeutic possibilities of exposure to light was triggered by a patient, Herbert Kern. He suffered from episodic depressive and manic complaints and discovered, by registering these over the years, a seasonal pattern in their occurrence. Discussions with scientists of the NIMH resulted in his participation in a bright light-treatment experiment when he was depressed in the winter of 1980-1981. He recovered. Next, the same group of investigators defined the criteria for a new syndrome, Seasonal Affective Disorder (SAD): a history of major affective disorder (according to the Research Diagnostic Criteria), at least two consecutive years in which the depressions have occurred during fall or winter and remitted in the following spring or summer, and the absence of any clear-cut seasonally changing psychosocial variable, such as work, stress and so on.

Seasonal changes in affective state in samples of Asian and white women

Seasonality of the affective state has been reported to vary in direct proportion to latitude in temperate regions. The frequency of seasonal affective disorder (SAD) and the severity of the symptoms associated with it have been reported to be greater in higher than in lower latitudes. In addition, recent research has suggested a genetic loading for SAD. Most of the research on the seasonality of affect has been done in high latitude areas, seasonal mood cycles have been infrequently investigated in tropical areas, and no study has so far measured and compared seasonal changes in affect and behaviour in indigenous and populations non-indigenous to high latitudes. To rule out the biases associated with retrospective designs, a prospective longitudinal study was designed to investigate seasonal mood variations in indigenous white and non-indigenous Asian populations. Since previous research has indicated the excessive vulnerability of women to winter depression, it was decided to measure seasonality of the affective state only in women. To examine the relative effects of genetic predispositions and physical environment, the Asian group was further divided into "Asian" and "Asian-British". The former group comprised women who were living in England but who had been born and had spent considerably more time in their country of origin, while the latter group consisted of women who were born in England and who had lived there all their lives. The three groups of 25 women each were matched for age and socio-economic status, and were interviewed every month for 1 year using the Hospital Anxiety and Depression Scale (HAD), a Behavioural Change Inventory (BCI), the Ladder Scale of General Well-being (LSW) and a Monthly Stress Inventory (MSI). One retrospective scale was administered at the end of the study year to compare the extent of seasonal change in affect with that on the HAD-depression subscale. The results showed that seasonal depression peaked in winter in all three groups, with the incidence of winter depression being highest in the Asian group. Seasonal changes on several dimensions of behaviour were in the direction of winter depression for all three groups. States other than depression (anxiety and general well-being) did not show any seasonal variation. Hours of daylight was found to be the best predictor of seasonal variation in mood among environmental and psychosocial variables. There was no evidence to support a genetic hypothesis for SAD.

Seasonal changes in affective state measured prospectively and retrospectively

BACKGROUND

The study was designed to investigate whether seasonal mood and behavioural changes are detectable prospectively in a non-clinical population in the way they have been reported in retrospective studies. The specificity of any seasonal fluctuation in affective state was also investigated by measuring anxiety as well as depression.

METHOD

To measure seasonal fluctuations in affect and behaviour prospectively, 25 women were interviewed every month for one year using four scales (depression, anxiety, stress, and behavioural change). Retrospective accounts of mood and behaviour at the end of the year were collected with the Seasonal Pattern and Assessment Questionnaire (SPAQ).

RESULTS

Seasonal depression peaked in winter as did atypical behaviour when measured either prospectively or retrospectively, but the difference between winter and summer was much more pronounced in the retrospective data. No seasonal effect was found for anxiety or psychosocial stressors.

CONCLUSIONS

The results obtained by retrospective techniques have limited reliability. In the future, more prospective studies with unbiased, standardised instruments are recommended to measure seasonal variations in affect and behaviour.

Biological rhythms in the human life cycle and their relationship to functional changes in the suprachiasmatic nucleus

Biological rhythms play a prominent role in the human life cycle. The endogenous rhythms are entrained by the environment and have an astronomical counterpart which is obvious for daily, monthly, and yearly rhythms, and may possibly also be present in weekly rhythms. Circadian rhythms are present in, e.g. testosterone levels, spontaneous birth, strokes, and death from cardiovascular causes. Circaseptan rhythms are present in, e.g. spontaneous birth, 17-ketosteroid levels, myocardial infarctions, and strokes. The relationship of these rhythms with the suprachiasmatic nucleus (SCN) has not yet been established. Circatrigintan rhythms, such as the menstrual cycle, have so far not been associated with the SCN. Circannual rhythms are present in, e.g. mood, suicides, reproduction, birth weight, sleep and season of birth of psychiatric patients. The human SCN shows strong circadian and circannual fluctuations in the number of neurons expressing vasopressin. The vasopressin and VIP cell population of the SCN develop late, i.e. for a major part postnatally. After the age of 50 the amplitudes of circadian and circannual fluctuations of the vasopressin cell numbers are reduced whereas the number of vasopressin expressing neurons decreases after the age of 80 and do so even more and earlier in Alzheimer's disease. Sex differences are present in the shape of the vasopressin subnucleus of the SCN and in the vasoactive intestinal polypeptide (VIP) cell number. The sex differences in the SCN, the doubling of the number of vasopressin neurons in the SCN of homosexual men, and a variety of animal experimental observations indicate that the SCN is involved in sexual behavior and reproduction. The exact role of the SCN in these processes is subject to current research.

Melatonin in light treatment of patients with seasonal and nonseasonal depression

Melatonin as a marker of circadian rhythm and the effect of bright light on melatonin were studied in 63 depressed patients, 42 with a seasonal pattern and 21 with a nonseasonal pattern. The patients were matched for age, time of treatment and severity of depression. Before light treatment, blood was sampled for melatonin and depression was clinically rated with the Comprehensive Psychopathological Rating Scale and Hamilton Depression Rating Scale. Two hours of light treatment, 350 cd/m2, was given daily for 10 days 0600 to 0800 or 1800 to 2000. Of the 42 patients with seasonal depression, 26 were treated with morning light and, 16 with evening light. The melatonin amplitude was significantly decreased by light, and the melatonin phase position was advanced by morning light and delayed by evening light. All patients except for 3 in each group changed in the expected direction. Although the patients with seasonal pattern had a more favorable outcome than patients with nonseasonal pattern, there was no difference in therapeutic outcome related to the baseline melatonin phase position. The hypothesis that the short term clinical effects of light therapy either in the morning or evening are related to pretreatment melatonin levels or alteration of melatonin amplitude or phase position was not supported in the study. There was also no significant difference between the seasonal and nonseasonal patients related to the degree of light suppression of melatonin and the rebound effect of serum melatonin levels following bright level exposure between 2200 and 2300 before regular light treatment.