Edwin M. Tam

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.

Efficacy of Bright Light Treatment, Fluoxetine, and the Combination in Patients With Nonseasonal Major Depressive Disorder: A Randomized Clinical Trial

IMPORTANCE Bright light therapy is an evidence-based treatment for seasonal depression, but there is limited evidence for its efficacy in nonseasonal major depressive disorder (MDD). OBJECTIVE To determine the efficacy of light treatment, in monotherapy and in combination with fluoxetine hydrochloride, compared with a sham-placebo condition in adults with nonseasonal MDD. DESIGN, SETTING, AND PARTICIPANTS Randomized, double-blind, placebo- and sham-controlled, 8-week trial in adults (aged 19-60 years) with MDD of at least moderate severity in outpatient psychiatry clinics in academic medical centers. Data were collected from October 7, 2009, to March 11, 2014. Analysis was based on modified intent to treat (randomized patients with ≥1 follow-up rating). INTERVENTIONS Patients were randomly assigned to (1) light monotherapy (active 10,000-lux fluorescent white light box for 30 min/d in the early morning plus placebo pill); (2) antidepressant monotherapy (inactive negative ion generator for 30 min/d plus fluoxetine hydrochloride, 20 mg/d); (3) combination light and antidepressant; or (4) placebo (inactive negative ion generator plus placebo pill). MAIN OUTCOMES AND MEASURES Change score on the Montgomery-Åsberg Depression Rating Scale (MADRS) from baseline to the 8-week end point. Secondary outcomes included response (≥50% reduction in MADRS score) and remission (MADRS score ≤10 at end point). RESULTS A total of 122 patients were randomized (light monotherapy, 32; fluoxetine monotherapy, 31; combination therapy, 29; placebo, 30). The mean (SD) changes in MADRS score for the light, fluoxetine, combination, and placebo groups were 13.4 (7.5), 8.8 (9.9), 16.9 (9.2), and 6.5 (9.6), respectively. The combination (effect size [d] = 1.11; 95% CI, 0.54 to 1.64) and light monotherapy (d = 0.80; 95% CI, 0.28 to 1.31) were significantly superior to placebo in the MADRS change score, but fluoxetine monotherapy (d = 0.24; 95% CI, -0.27 to 0.74) was not superior to placebo. For the respective placebo, fluoxetine, light, and combination groups at the end point, response was achieved by 10 (33.3%), 9 (29.0%), 16 (50.0%), and 22 (75.9%) and remission was achieved by 9 (30.0%), 6 (19.4%), 14 (43.8%), and 17 (58.6%). Combination therapy was superior to placebo in MADRS response (β = 1.70; df = 1; P = .005) and remission (β = 1.33; df = 1; P = .02), with numbers needed to treat of 2.4 (95% CI, 1.6 to 5.8) and 3.5 (95% CI, 2.0 to 29.9), respectively. All treatments were generally well tolerated, with few significant differences in treatment-emergent adverse events. CONCLUSIONS AND RELEVANCE Bright light treatment, both as monotherapy and in combination with fluoxetine, was efficacious and well tolerated in the treatment of adults with nonseasonal MDD. The combination treatment had the most consistent effects. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00958204.

Electroretinography in patients with winter seasonal affective disorder.

A retinal sensitivity abnormality has been hypothesized in seasonal affective disorder (SAD). To explore this hypothesis, the electroretinogram (ERG) was used to assess retinal sensitivity at the level of the rod photoreceptor system. We examined 27 depressed patients who met DSM-III-R criteria for major depression, recurrent, with a seasonal (winter) pattern and 23 normal control subjects who were age-paired and sex-matched as much as possible with the SAD patients. ERG testing was performed in dark-adapted, dilated eyes in winter between 10:00 and 15:00 h. Retinal sensitivity was based on the light stimulus intensity necessary to reach a 50-microV amplitude threshold. We found that retinal sensitivity was significantly lower (0.21 log units) in SAD patients compared with normal control subjects and that 55% of the patients had a retinal sensitivity value one standard deviation lower than the mean value of the control subjects. These results are consistent with a retinal hyposensitivity hypothesis for SAD, but the explanation for lower rod photoreceptor sensitivity in SAD is not known. We hypothesize that brain neurotransmitter dysregulation may be at the origin of both the mood disorder and retinal sensitivity change.

Atypical depressive symptoms and clusters in unipolar and bipolar depression

In order to examine differences in the atypical symptoms of depression between unipolar and bipolar patients, we studied 109 depressed patients (79 unipolar and 30 bipolar subjects) diagnosed with DSM‐IV criteria. Patients were assessed using the Atypical Depression Diagnostic Scale (ADDS), a semi‐structured interview that rates mood reactivity and other atypical depressive symptoms. Although atypical depression was common in this sample (28% of cases with definite atypical depression), no differences were found between the unipolar and bipolar patients in either the atypical symptom profile or the prevalence of an atypical depression diagnosis. The interrelationships between the atypical symptoms were also examined using a hierarchical cluster analysis. A five‐cluster solution maximized differences between groups, with results suggesting that atypical depression may be a heterogeneous diagnosis.

A controlled trial of the Litebook light-emitting diode (LED) light therapy device for treatment of Seasonal Affective Disorder (SAD)

BackgroundRecent research has emphasized that the human circadian rhythm system is differentially sensitive to short wavelength light. Light treatment devices using efficient light-emitting diodes (LEDs) whose output is relatively concentrated in short wavelengths may enable a more convenient effective therapy for Seasonal Affective Disorder (SAD).MethodsThe efficacy of a LED light therapy device in the treatment of SAD was tested in a randomized, double-blind, placebo-controlled, multi-center trial. Participants aged 18 to 65 with SAD (DSM-IV major depression with seasonal pattern) were seen at Baseline and Randomization visits separated by 1 week, and after 1, 2, 3 and 4 weeks of treatment. Hamilton Depression Rating Scale scores (SIGH-SAD) were obtained at each visit. Participants with SIGH-SAD of 20 or greater at Baseline and Randomization visits were randomized to active or control treatment: exposure to the Litebook LED treatment device (The Litebook Company Ltd., Alberta, Canada) which delivers 1,350 lux white light (with spectral emission peaks at 464 nm and 564 nm) at a distance of 20 inches or to an inactivated negative ion generator at a distance of 20 inches, for 30 minutes a day upon awakening and prior to 8 A.M.ResultsOf the 26 participants randomized, 23 completed the trial. Mean group SIGH-SAD scores did not differ significantly at randomization. At trial end, the proportions of participants in remission (SIGH-SAD less than 9) were significantly greater (Fishers exact test), and SIGH-SAD scores, as percent individual score at randomization, were significantly lower (t-test), with active treatment than with control, both in an intent-to-treat analysis and an observed cases analysis. A longitudinal repeated measures ANOVA analysis of SIGH-SAD scores also indicated a significant interaction of time and treatment, showing superiority of the Litebook over the placebo condition.ConclusionThe results of this pilot study support the hypothesis that light therapy with the Litebook is an effective treatment for SAD.Trial registrationClinicaltrials.gov: NCT00139997

Effects of rapid tryptophan depletion in patients with seasonal affective disorder in natural summer remission

BACKGROUND Serotonergic mechanisms have been proposed for the pathophysiology of seasonal affective disorder (SAD) and the therapeutic effect of bright-light treatment. Previously, we showed that SAD patients, in clinical remission with light therapy during the winter, experienced transient depressive relapses after a rapid tryptophan depletion (RTD) technique, which results in decreased brain serotonin levels. The objective of this study was to investigate the effect of RTD in SAD patients who were in natural summer remission. METHODS Twelve drug-free patients with SAD by DSM-IV criteria and 10 normal subjects participated in this double-blind, placebo-controlled, crossover study. SAD patients were in natural summer remission for at least 8 weeks. Behavioural ratings and plasma tryptophan levels were obtained before, and 5 h after, ingesting an amino acid (AA) mixture +/- tryptophan. Experimental RTD and control sessions were scheduled 1 week apart. RESULTS The RTD session resulted in significant reduction in total and free plasma tryptophan levels compared to the control session. The behavioural data were analysed using repeated measures analysis of variance. This analysis found significant main effects of time (higher scores after AA ingestion) and diagnosis (higher scores in SAD patients), but no main effect of session or significant interaction effects between the three factors. Thus, there were no significant behavioural effects of RTD compared to the sham depletion control session. CONCLUSIONS The summer remission experienced by SAD patients is not dependent on plasma tryptophan levels (and presumably brain serotonin function) in the same manner as that of remission after light therapy. These results conflict with those of other laboratories, perhaps because of differences in study samples.

Atypical depressive symptoms in seasonal and non-seasonal mood disorders

The authors examined the rates of atypical depression and prevalence of specific atypical symptoms in patients with seasonal versus non-seasonal depression. Fifty-three patients with seasonal affective disorder (SAD) were compared to 54 patients with non-seasonal major depressive disorder (MDD) using the atypical depression diagnostic scale (ADDS). SAD patients scored significantly higher than non-seasonal MDD patients in hyperphagia and hypersomnia, and significantly lower in interpersonal sensitivity and other rejection avoidance. There was no difference in the rate of ADDS diagnosis of atypical depression. Differences between atypical depression and SAD suggest that they are separate subtypes of depression with an overlapping symptom picture.

Effects of Alpha-Methyl-Para-Tyrosine-Induced Catecholamine Depletion in Patients with Seasonal Affective Disorder in Summer Remission

Noradrenergic and dopaminergic mechanisms have been proposed for the pathophysiology of seasonal affective disorder (SAD). We investigated the effects of catecholamine depletion using α-methyl-para-tyrosine (AMPT), an inhibitor of tyrosine hydroxylase, in patients with SAD in natural summer remission. Nine drug-free patients with SAD by DSM-IV criteria, in summer remission for at least eight weeks, completed a double-blind, crossover study. Behavioral ratings and serum HVA and MHPG levels were obtained for 3-day sessions during which patients took AMPT or an active control drug, diphenhydramine.The active AMPT session significantly reduced serum levels of HVA and MHPG compared with the control diphenhydramine session. The AMPT session resulted in higher depression ratings with all nine patients having significant clinical relapse, compared with two patients during the diphenhydramine session. All patients returned to baseline scores after drug discontinuation. Catecholamine depletion results in significant clinical relapse in patients with SAD in the untreated, summer-remitted state. AMPT-induced depressive relapse may be a trait marker for SAD, and/or brain catecholamines may play a direct role in the pathogenesis of SAD.

L-tryptophan augmentation of light therapy in patients with seasonal affective disorder

Objective Up to one-third of patients with seasonal affective disorder (SAD) do not have a full response to light therapy. Given the evidence for serotonergic dysregulation in SAD, we examined the possible role of l-tryptophan as an augmentation strategy for nonresponders and partial responders to light therapy. Method Eligible drug-free patients meeting DSM-IV criteria for SAD were treated for 2 weeks using a standard morning light therapy regimen (10 000 lux cool-white fluorescent light for 30 minutes). Partial and nonresponders were treated for 2 weeks with open-label l-tryptophan (1 g 3 times daily) while light therapy was continued. Ratings at baseline and follow-up included the 29-item Structured Interview Guide for the Hamilton Depression Rating Scale, SAD version (SIGH-SAD) and the Clinical Global Impression (CGI) scale. Results Sixteen patients began the l-tryptophan augmentation phase. Two patients discontinued medications within 3 days because of side effects. In the 14 patients completing treatment, the addition of l-tryptophan resulted in significant reduction of mean depression scores. Nine of 14 patients (64%) showed very good clinical responses to combined treatment and minimal side effects. Conclusion This open-label study suggests that l-tryptophan may be an effective augmentation strategy for those patients with SAD who show limited or poor response to bright light therapy. Further placebo-controlled studies are warranted to demonstrate efficacy.

Cortisol, Hypothermic, and Behavioral Responses to Ipsapirone in Patients with Bipolar Depression and Normal Controls

To examine if 5-HT1A receptor function is involved in the pathophysiology of bipolar depression, we measured the cortisol, hypothermic and behavioral responses to ipsapirone, a 5-HT1A receptor agonist, in 8 patients with bipolar depression and 26 normal controls. After obtaining blood samples for baseline cortisol levels and measuring baseline body temperature, a single dose of 0.3 mg/kg of ipsapirone was administered orally to all the subjects, and further blood and temperature readings were obtained every 30 min for 3 h. The results showed that the administration of ipsapirone led to a significant increase in cortisol release and a significant decrease in body temperature both in bipolar depressed patients and normal controls. There was no significant difference in the cortisol or hypothermic responses to ipsapirone between groups. However, there was a significant positive correlation between the Hamilton Depression Rating (HAMD) scores and the hypothermic response in the depressed patients, while the HAMD scores were not significantly correlated with the cortisol response. Comparing our findings with those of previous studies, we suggest that the alterations in 5-HT1A receptor sensitivity in depressed patients may be related to the severity of depression, and they may only occur in more severely depressed patients.