Treating depression with botulinum toxin: a pooled analysis of randomized controlled trials

INTRODUCTION

Botulinum toxin A (BTA) injection into the glabellar region is currently being studied as a treatment for major depressive disorder (MDD). Here we explore efficacy data of this novel approach in a pooled analysis.

METHODS

A literature search revealed 3 RCTs on this topic. Individual patient data and clinical end points shared by these 3 trials were pooled and analyzed as one study (n=134) using multiple regression models with random effects.

RESULTS

In the pooled sample, the BTA (n=59) and the placebo group (n=75) did not differ in the baseline variables. Efficacy outcomes revealed BTA superiority over placebo: Improvement in the Hamilton Depression Rating Scale or Montgomery-Asberg Depression Rating Scale 6 weeks after baseline was 45.7% for BTA vs. 14.6% for placebo (p<0.0001), corresponding to a BTA response rate of 54.2% (vs. 10.7%) and a BTA remission rate of 30.5% (vs. 6.7%).

DISCUSSION

Equalling the status of a meta-analysis, this study increases evidence that a single treatment of BTA into the glabellar region can reduce symptoms of MDD. Further studies are needed to better understand how BTA exerts its mood-lifting effect.

Plasma leptin in men and women with seasonal affective disorder and in healthy matched controls

Seasonal affective disorder (SAD) is a specific clinical entity characterized by recurrent episodes of depression, which typically occur during the winter with periods of remission during the spring and summer. These depression episodes are accompanied by hyperphagia with cravings for carbohydrates and moderate weight gain, and usually respond to light therapy. We examined potential relationships between leptin, a hormone known to affect appetite and weight regulation, and seasonal changes in mood and appetite by measuring plasma leptin, clinical severity of depression, appetite scores, and body mass index (BMI) in 19 women and 8 men with SAD and matched controls (20 women and 8 men) in the summer and winter. Plasma leptin was positively correlated with BMI in patients and controls during both seasons. Women and men with SAD both experienced depression in the winter, which was associated with increased appetite, caloric intake, and carbohydrate craving. Increased body weight during the winter in subjects with SAD was paralleled by a lack of concomitant changes in plasma leptin, which suggests that leptin sensitivity to changes in body weight may be influenced by seasons in subjects with SAD, similar to seasonal mammals.

A circadian signal of change of season in patients with seasonal affective disorder

BACKGROUND

In animals, the circadian pacemaker regulates seasonal changes in behavior by transmitting a signal of day length to other sites in the organism. The signal is expressed reciprocally in the duration of nocturnal melatonin secretion, which is longer in winter than in summer. We investigated whether such a signal could mediate the effects of change of season on patients with seasonal affective disorder.

METHODS

The duration of melatonin secretion in constant dim light was measured in winter and in summer in 55 patients and 55 matched healthy volunteers. Levels of melatonin were measured in plasma samples that were obtained every 30 minutes for 24 hours in each season.

RESULTS

Patients and volunteers responded differently to change of season. In patients, the duration of the nocturnal period of active melatonin secretion was longer in winter than in summer (9.0 +/- 1.3 vs 8.4 +/- 1.3 hours; P=.001) but in healthy volunteers there was no change (9.0 +/- 1.6 vs 8.9 +/- 1.2 hours; P=.5).

CONCLUSIONS

The results show that patients with seasonal affective disorder generate a biological signal of change of season that is absent in healthy volunteers and that is similar to the signal that mammals use to regulate seasonal changes in their behavior. While not proving causality, this finding is consistent with the hypothesis that neural circuits that mediate the effects of seasonal changes in day length on mammalian behavior mediate effects of season and light treatment on seasonal affective disorder.

Band-specific electroencephalogram and brain cooling abnormalities during NREM sleep in patients with winter depression

BACKGROUND

We previously reported that delta wave activity and facial skin temperatures, an index of brain cooling activity, were both abnormal during sleep in patients with winter depression (SAD). Because other electroencephalographic (EEG) frequencies may also convey relevant thermal, homeostatic, and circadian information, we sought to spectrally analyze delta, theta, alpha, and sigma frequencies during sleep from 23 patients with SAD and 23 healthy control subjects.

METHODS

We computed means for delta, theta, alpha, and sigma power during both NREM and REM sleep. We also generated 22 cross-correlation functions for each group by crossing facial and rectal temperature with each other, as well as with delta, theta, alpha, and sigma frequencies.

RESULTS

We found that delta, theta, and alpha frequency activities were all increased during NREM, but not REM sleep, in patients with SAD. In addition, there were significant and abnormal cross-correlations between facial temperatures and delta and theta frequencies during NREM sleep in patients with SAD.

CONCLUSIONS

Patients with winter depression exhibit correlated abnormalities of sleep homeostasis and brain cooling during NREM sleep. Their EEG profiles during NREM sleep resemble the EEG profiles of subjects who have been sleep deprived. Further studies of NREM sleep homeostasis in patients with SAD seem warranted.

Early response to light therapy partially predicts long-term antidepressant effects in patients with seasonal affective disorder

OBJECTIVE

To determine if the antidepressant effect of 1 hour of light therapy is predictive of the response after 1 and 2 weeks of treatment in patients with seasonal affective disorder (SAD).

PATIENTS

Twelve patients with SAD.

SETTING

National Institutes of Health Clinical Center, Bethesda, Md.

INTERVENTIONS

Light therapy for 2 weeks.

OUTCOME MEASURES

Scores on the Seasonal Affective Disorder Version of the Hamilton Depression Rating Scale (SIGH-SAD) on 4 occasions (before and after 1 hour of light therapy and after 1 and 2 weeks of therapy) in the winter when the patients were depressed. Change on typical and atypical depressive scores at these time points were compared.

RESULTS

Improvement of atypical depressive symptoms after 1 hour of light therapy positively correlated with improvement after 2 weeks of therapy.

CONCLUSION

In patients with SAD, the early response to light therapy may predict some aspects of long-term response to light therapy, but these results should be treated with caution until replicated.

Pleiotropy of the serotonin transporter gene for seasonality and neuroticism

Pleiotropy refers to the ability of a single gene to influence multiple traits. A polymorphism in the regulatory region of the serotonin transporter gene (5-HTTLPR) has previously been found to be associated both with the personality trait of neuroticism and with seasonal changes in mood and behavior, or seasonality. Hypothesizing that the contribution of the serotonin transporter gene to seasonality is specific, i.e. independent of neuroticism, we measured 5-HTTLPR genotypes and both psychological traits in 236 healthy volunteers. The results indicated that the 5-HTTLPR contributions to variation in the two traits are largely independent; approximately three-quarters of the effect of the gene on seasonality are not related to its effects on neuroticism. Moreover, the gene has a larger effect on the covariation between neuroticism and seasonality than it does on either trait alone. Sibling-pair analysis confirmed that the effects of the 5-HTTLPR are due to genetic pleiotropy rather than population stratification.

Self-reported sensitivity to chemical exposures in five clinical populations and healthy controls

Two hundred and twenty-five subjects, including normal volunteers and patients with previously documented seasonal affective disorder (SAD), chronic fatigue syndrome (CFS), Cushing's syndrome, Addison's disease and obsessive-compulsive disorder (OCD), completed a self-rated inventory of reported sensitivity to various chemical exposures. Patients with CFS, Addison's disease and SAD self-reported more sensitivity to chemical exposures than normal controls. In addition, women reported more sensitivity than men. This report suggests that chemical sensitivity may be a relevant area to explore in certain medical and psychiatric populations. A possible relationship between reported chemical sensitivity and hypothalamic-pituitary-adrenal (HPA)-axis functioning is discussed.

Ultradian oscillations in cranial thermoregulation and electroencephalographic slow-wave activity during sleep are abnormal in humans with annual winter depression

The level of core body, and presumably brain temperature during sleep varies with clinical state in patients with seasonal affective disorder (SAD), becoming elevated during winter depression and lowered during clinical remission induced by either light treatment or summer. During sleep, brain temperatures are in part determined by the level of brain cooling activity, which may be reflected by facial skin temperatures. In many animals, the level of brain cooling activity oscillates across the NREM-REM sleep cycle. Facial skin temperatures during sleep in patients with winter depression are abnormally low and uncorrelated with rectal temperatures, although their relationship to EEG-defined sleep stages remains unknown. We therefore measured the sleep EEG, core body and facial skin temperatures in 23 patients with winter depression and 23 healthy controls, and tested the hypothesis that ultradian oscillations in facial skin temperatures exist in humans and are abnormal in patients with winter depression. We found that facial skin temperatures oscillated significantly across the NREM-REM sleep cycle, and were again significantly lower and uncorrelated with rectal temperatures in patients with winter depression. Mean slow-wave activity and NREM episode duration were significantly greater in patients with winter depression, whereas the intraepisodic dynamics of slow-wave activity were normal in patients with winter depression. These results suggest that brain cooling activity oscillates in an ultradian manner during sleep in humans and is reduced during winter depression, and provide additional support for the hypothesis that brain temperatures are elevated during winter depression.

Seasonal variations in mood and behavior among Chinese medical students

OBJECTIVE

The goal of this study was to estimate the frequency of seasonal variations in mood and behavior among Chinese medical students.

METHOD

A total of 1,358 medical students were surveyed with Chinese versions of the Seasonal Pattern Assessment Questionnaire and the Beck Depression Inventory in Jining, China.

RESULTS

The mean global seasonality score was 8.3 (SD=3.6) out of a possible 24; 81.7% (N=1,110) of the subjects reported some trouble adapting to changing seasons. Summer difficulties were more common than winter difficulties by a ratio of 3:2; estimated rates of summer seasonal affective disorder and subsyndromal seasonal affective disorder were 4.4% and 8.0%, respectively, compared with corresponding winter rates of 2.4% and 5.7%.

CONCLUSIONS

These results suggest that seasonal variations in mood and behavior are common in China. The predominance of summer difficulties stands in contrast to that in most Western studies and is consistent with the only other published study performed in Asia.

Summer and winter patterns of seasonality in Chinese college students: a replication

The goal of this study is to replicate an earlier epidemiological finding of seasonal changes in mood and behavior among Chinese medical students using an independent study population. Three hundred nineteen college students were surveyed with a Chinese version of the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Beck Depression Inventory (BDI) in Jining, China, during March of 1996. The frequency of seasonal patterns and prevalence rates of seasonal affective disorder (SAD) were estimated and compared with data from the medical student survey conducted in the same city. The mean Global Seasonality Score (GSS) of this college student sample was 9.9 +/- 4.9; 84% of the subjects reported some problems with the changing seasons. Summer difficulties were more prevalent than winter difficulties by a ratio of 1.9 to 1 (38.9% v 20.1%). The estimated rates of summer SAD and subsyndromal-SAD (s-SAD) were 7.5% and 11.9%, respectively, as compared with the corresponding winter figures of 5.6% and 6.3%. In addition, the prevalence estimates of winter pattern or winter SADs were higher in males than in females, but the corresponding summer figures showed no gender difference. Compared with the data from the medical student survey, this college student sample had a higher GSS (P < .01) but comparable summer to winter and female to male ratios for the prevalence of SADs (P > .05). These results replicate our previous findings that seasonal problems are common in China, but the predominant problems are summer difficulties rather than winter difficulties, and there is no female preponderance in the prevalence estimates of such problems. Both findings stand in contrast to most Western studies but are consistent with the only other published study performed in the Orient.

A patient who changed my practice: Herb Kern, the first light therapy patient

This paper presents the case of Herb Kern, the first patient with clear-cut seasonal mood cycles in whom light therapy was used to reverse depression. His successful treatment was an inspiration to the author to define the syndrome of Seasonal Affective Disorder (SAD) and use light therapy as a systematic controlled treatment for this condition. This is an example of how a single patient can lead to the recognition of a common condition and a novel treatment modality.

Free thyroxine and thyroid-stimulating hormone levels in patients with seasonal affective disorder and matched controls

Seasonal affective disorder (SAD) is characterized by recurrent episodes of depression in the fall and winter that alternate with nondepressed periods in the spring and summer. Because some symptoms of SAD, such as decreased energy and weight gain, also occur in hypothyroidism, it is possible that individuals with SAD have a subtle decrease in thyroid function. To test this hypothesis, we studied blood levels of free thyroxine (T4) and thyroid-stimulating hormone (TSH) in SAD patients and matched controls in the winter. We found that free T4 blood levels were slightly but significantly lower in patients than in healthy volunteers. The difference between TSH levels in SAD patients and controls was not statistically significant. Future research will be needed to determine whether the difference in thyroid function between SAD patients and controls is an epiphenomenon or is related to the biological mechanisms that cause symptoms of SAD.

Monorhinal odor identification and depression scores in patients with seasonal affective disorder

BACKGROUND

Visual and olfactory pathways are interconnected. Olfactory deafferentation unmasks photoperiodic responsiveness in some nonphotoperiodic animals such as laboratory rats. By analogy, we hypothesized that olfactory deficits may unmask seasonal rhythms in certain individuals, namely those with seasonal affective disorder (SAD). Since previous studies suggest lateralized hemispheric dysfunction in SAD, and since olfactory neurons' primary projections are largely ipsilateral, we assessed olfactory identification performance on both the right and left side of the nose.

METHODS

Twenty-four patients with SAD and 24 matched controls were studied using a phenyl ethyl alcohol detection threshold test bilaterally and the University of Pennsylvania Smell Identification Test unilaterally. Subjects rated their mood using the Self Assessment Mood Scale for SAD. Patients' testing was done in both 'depressed' and 'improved on light' states.

RESULTS

No difference in olfactory performance was found between patients and controls or between patients before and after light treatment. However, right-side identification scores were negatively correlated with 'typical' depression scores (r = -0.56, P = 0.006), while left-side olfactory scores were not. Atypical depression scores were unrelated to olfactory performance. Similar correlations emerged between the olfactory identification laterality quotient (Right - Left)/(Right + Left) and typical depressive scores (r = - 0.64, P < 0.001) and total depression scores (r = - 0.59, P < 0.004).

LIMITATIONS

We studied a demographically heterogeneous sample and did not control for menstrual factors.

DISCUSSION

Our results add to previous evidence of lateralized hemispheric involvement in SAD and suggest that olfaction may be related to seasonal emotional rhythms in humans.

Seasonal mood change and neuroticism: the same construct?

The personality trait of neuroticism has been found to be associated with a polymorphism in the regulatory region of the serotonin (5-HT) transporter gene (5-HTTLPR). This same genetic polymorphism has also been associated with seasonal changes in mood and behavior, or seasonality. The purpose of the current study was to determine whether seasonality and neuroticism are actually the same construct given that they are both associated with the same genetic polymorphism. We administered the Seasonal Pattern Assessment Questionnaire (SPAQ), which measures the severity of seasonality, and the Revised NEO Personality Inventory (NEO-PI-R), which measures the severity of neuroticism, to 45 subjects diagnosed with seasonal affective disorder (SAD). SAD is a clinical expression of seasonality in which patients develop a major depressive disorder in the winter that remits in the summer and can be treated with light therapy. No significant correlation was found between neuroticism and seasonality. We conclude that seasonality and neuroticism are not the same construct, even though the 5-HTTLPR polymorphism is a genetic risk factor for each.

The role of genetic factors in the etiology of seasonal affective disorder and seasonality

The study of the genetic basis of seasonal affective disorder (SAD), a condition where depressions in fall and winter alternate with nondepressed periods in the spring and summer, has recently received attention. The data on the genetics of seasonal affective disorders are of three types: 1. Familiality: Studies on the prevalence of psychiatric disorders among relatives of patients with SAD suggested a familial contribution to the development of SAD; 2. Heritability: A survey of a cohort of twins showed that genetic effects exert a global influence across a variety of behavioral traits and accounted for at least 29% of the variance in seasonality in men and women; 3. Molecular genetic research: two genetic variants related to serotonergic transmission, the 5-HTTLPR and the 5-HT2A-1438G/A gene promoter polymorphisms, are associated with SAD; the former but not the latter polymorphism is related to seasonality. Future research may clarify the role of different genes in the development of SAD.

Gender differences in glycosylated hemoglobin levels in seasonal affective disorder patients and controls

Seasonal affective disorder (SAD) has been shown to manifest different symptoms in female and male patients. Specifically, women with SAD have been shown to have greater increases in overeating, weight gain, and increased sleep as compared with their male counterparts. Given these dietary changes, we predicted that female SAD patients would exhibit increased glycosylated hemoglobin (HbA1) levels, indicative of chronically elevated glucose levels. Twenty-two patients (15 women and seven men) and matched controls were enrolled during the winter season and tested for HbA1 levels. A three-way analysis of variance (ANOVA; gender x group x season) was insignificant and the result was a negative study. After the initial hypothesis was rejected, we undertook a post-hoc analysis of the data, from which emerged that in winter, women patients had higher HbA1 levels as compared with matched controls. As our original hypothesis was rejected, we cannot accept the results of the post-hoc study. However, numerous other studies have demonstrated that female and male SAD patients differ in their pathophysiology, and are suggestive that in future analyses ought to consider analyzing subjects separately across gender.

Serotonin hypothesis of winter depression: behavioral and neuroendocrine effects of the 5-HT(1A) receptor partial agonist ipsapirone in patients with seasonal affective disorder and healthy control subjects

Winter depressions in seasonal affective disorder (SAD) are associated with central serotonergic (5-HT) dysfunction. SAD patients demonstrate rather specific, state-dependent, abnormal increases in 'activation-euphoria' ratings following intravenous infusion of the 5-HT receptor agonist meta-chlorophenylpiperazine (m-CPP). Several studies are also consistent with abnormal serotonergic regulation of the hypothalamic-pituitary-adrenal (HPA) axis in SAD. Here, we investigated the effects of the 5-HT1A receptor partial agonist ipsapirone, which produces behavioral effects and HPA-axis activation, to further characterize the 5-HT receptor subtype-specificity of these disturbances in SAD. Eighteen SAD patients and 18 control subjects completed two drug challenges (ipsapirone 0.3 mg/kg and placebo) separated by 3-5 days in randomized order. We measured behavioral responses with the NIMH self-rating scale, and plasma ACTH, cortisol, and prolactin concentrations. Compared with placebo, ipsapirone was associated with significant increases in self-rated 'functional deficit' and 'altered self-reality', and in each of the hormones. There were no differences between groups on any measures. The level of depression in SAD patients was inversely correlated with their ipsapirone-induced cortisol responses. There were significant drug x order effects on baseline 'anxiety' scores, ACTH and cortisol concentrations, such that subjects were significantly more stressed (higher 'anxiety', ACTH and cortisol) prior to their first challenge compared with their second. In conclusion, post-synaptic 5-HT1A receptors appear to function normally in SAD. The previously observed m-CPP-induced behavioral abnormality may be mediated by either 5-HT2C or 5-HT7 receptors.

No coding variant of the tryptophan hydroxylase gene detected in seasonal affective disorder, obsessive-compulsive disorder, anorexia nervosa, and alcoholism

BACKGROUND

The goal of this study was to evaluate the role of genetic variation in the coding sequence of tryptophan hydroxylase (TPH) in the pathogenesis of several psychiatric diseases in which altered serotonin function has been implicated: bipolar affective disorder (BP), obsessive-compulsive disorder (OCD), anorexia nervosa (AN), seasonal affective disorder (SAD), panic disorder (PD), and alcoholism (Alc).

METHODS

Ninety-three percent of the TPH coding sequence was screened by polymerase chain reaction single-strand conformation polymorphism (SSCP) for DNA sequence variations in 128 AN, 88 OCD, 72 SAD, 45 PD, and 36 BP patients and 142 normal volunteers. Also included in the screening were 61 Alc randomly selected from a Finnish alcoholic population in which an association of a TPH intron 7 polymorphism with suicidality was previously observed. Polymorphisms detected by SSCP were characterized by DNA sequencing and by allele-specific restriction enzyme digestion. Genotyping was then performed in 34 Finnish alcoholic suicide attempters.

RESULTS

A rare silent mutation was identified in exon 10 and is designated T1095C. The C1095 allele was found in 1 OCD and in 2 AN subjects; all 3 individuals were heterozygous (C1095/T1095) for the variant allele. No association was observed between this TPH T1095C variant with either OCD, AN, Alc, or suicidality.

CONCLUSION

These results suggest that the coding sequence of the TPH gene does not contain abundant variants, and may not play a major role in vulnerability to several psychopathologies in which reduced serotonin turnover has been implicated.

The effects of seasons and light therapy on G protein levels in mononuclear leukocytes of patients with seasonal affective disorder

BACKGROUND

Information-transducing heterotrimeric G proteins have been implicated previously in the mechanism of action of mood stabilizers and in the pathophysiology of mood disorders. Mononuclear leukocytes of patients with unipolar and bipolar depression have been characterized by reduced measures of the stimulatory and inhibitory G proteins. In this study, patients with seasonal affective disorder (SAD) were measured for mononuclear leukocyte G protein levels while depressed during the winter, following light therapy, and in remission during the summer.

METHODS

Twenty-six patients with SAD and 28 healthy subjects were assessed in the study. The immunoreactivities of Gs alpha, Gi alpha, and Gbeta subunit proteins were determined by Western blot analysis of mononuclear leukocyte membranes with selective polyclonal antibodies for the various G subunit proteins, followed by densitometric quantitation using an image analysis system.

RESULTS

Untreated patients with SAD and winter, atypical-type depression showed significantly reduced mononuclear leukocyte immunoreactive levels of Gs alpha and Gi alpha proteins, similar to previous observations in patients with nonseasonal major depression. The reduced G protein levels were normalized with 2 weeks of light therapy. The same patients while in remission during the summer had G protein levels that were similar to those of healthy subjects.

CONCLUSIONS

G protein-immunoreactive measures in patients with SAD are suggested as a state marker for winter depression, which is normalized by light treatment and during the summer. We speculate that light may exert its effects via normalization of transducin (Gt protein) levels, which are thought to be reduced in winter depression.

Association between seasonal affective disorder and the 5-HT2A promoter polymorphism, -1438G/A

Genes involved in serotonin metabolism are good candidates for the pathogenesis of seasonal affective disorder (SAD). A functional variant in the serotonin transporter promoter, 5-HTTLPR, has recently been shown to be associated with SAD and seasonality. The purpose of this study was to determine whether -1438G/A, a polymorphism in the 5-HT2A promoter, is associated with SAD and seasonality, and whether it has additive effects with 5-HTTLPR on seasonality. Sixty-seven individuals with SAD and 69 normal volunteers, all screened with the SCID and diagnosed according to DSM-III-R criteria, were genotyped for the -1 438G/A 5-HT2A promoter polymorphism. All had been previously genotyped for 5-HTTLPR and had been assessed for seasonality by the Global Seasonality Scale. There was a significant increase in the frequency of the -1438A variant allele of the 5-HT2A promoter polymorphism in SAD patients (0.47) compared to matched controls (0.36) (P < 0.01). The difference in genotype distribution was also significant (P < 0.05). We found no association between the -1438G/A polymorphism and seasonality scores, and there was no additive effect with 5-HTTLPR on seasonality. In conclusion, we have shown that the -1438G/A 5-HT2A promoter variant is associated with SAD but not with seasonality. We suggest that the association may instead be with the depressive symptoms of SAD. However, these results should be treated with caution until replicated because of the possibility of false-positive findings in case-control association studies.

Greater improvement in summer than with light treatment in winter in patients with seasonal affective disorder

OBJECTIVE

The authors sought to compare the degree of mood improvement after light treatment with mood improvement in the subsequent summer in patients with seasonal affective disorder.

METHOD

By using the Seasonal Affective Disorder Version of the Hamilton Depression Rating Scale, the authors rated 15 patients with seasonal affective disorder on three occasions: during winter when the patients were depressed, during winter following 2 weeks of light therapy, and during the following summer. They compared the three conditions by using Friedman's analysis of variance and the Wilcoxon signed ranks test.

RESULTS

The patients' scores on the depression scale were significantly higher after 2 weeks of light therapy in winter than during the following summer.

CONCLUSIONS

Light treatment for 2 weeks in winter is only partially effective when compared to summer. Further studies will be necessary to assess if summer's light or other factors are the main contributors to this difference.

Serotonin 1A receptors, melatonin, and the proportional control thermostat in patients with winter depression

BACKGROUND

In patients with seasonal affective disorder, light treatment lowers core temperature during sleep in proportion to its antidepressant efficacy. The regulation of the level of core temperature during sleep is linked with a proportional control thermostat in the central nervous system whose operation appears abnormal in patients with seasonal affective disorder. Because both melatonin and serotonin 1A receptor activation also lower core temperature, we investigated the relationship between (1) endogenous melatonin and core temperature profiles, (2) the proportional control thermostat, and (3) the core hypothermic response to the serotonin 1A receptor partial agonist ipsapirone hydrochloride in patients with seasonal affective disorder and healthy controls.

METHODS

Eighteen patients with seasonal affective disorder and 18 controls first completed a 24-hour study in which their melatonin profiles were characterized. Subjects then returned 3 to 5 days later for the first of 2 drug challenges (ipsapirone hydrochloride, 0.3 mg/kg, or placebo), each separated by 3 to 5 days. Overnight rectal and facial temperatures were recorded before and after each drug challenge.

RESULTS

The magnitudes of the core hypothermic responses to ipsapirone were (1) not different between groups and (2) independently correlated with both the levels of the previous nights' core temperature minima (P=.002) and the amounts of nocturnal melatonin secreted (P<.001).

CONCLUSION

The daytime regulation of core temperature by serotonin 1A receptors appears normal in seasonal affective disorder. The magnitude of serotonin 1A receptor-activated hypothermia is governed by a central nervous system proportional control thermostat whose operation appears modulated by both melatonin and the level of the core temperature minimum.

Effects of tryptophan depletion vs catecholamine depletion in patients with seasonal affective disorder in remission with light therapy

BACKGROUND

Although hypotheses about the therapeutic mechanism of action of light therapy have focused on serotonergic mechanisms, the potential role, if any, of catecholaminergic pathways has not been fully explored.

METHODS

Sixteen patients with seasonal affective disorder who had responded to a standard regimen of daily 10000-lux light therapy were enrolled in a double-blind, placebo-controlled, randomized crossover study. We compared the effects of tryptophan depletion with catecholamine depletion and sham depletion. Ingestion of a tryptophan-free amino acid beverage plus amino acid capsules was used to deplete tryptophan. Administration of the tyrosine hydroxylase inhibitor alpha-methyl-paratyrosine was used to deplete catecholamines. Diphenhydramine hydrochloride was used as an active placebo during sham depletion. The effects of these interventions were evaluated with measures of depression, plasma tryptophan levels, and plasma catecholamine metabolites.

RESULTS

Tryptophan depletion significantly decreased plasma total and free tryptophan levels. Catecholamine depletion significantly decreased plasma 3-methoxy-4-hydroxyphenylethyleneglycol and homovanillic acid levels. Both tryptophan depletion and catecholamine depletion, compared with sham depletion, induced a robust increase (P<.001, repeated-measures analysis of variance) in depressive symptoms as measured with the Hamilton Depression Rating Scale, Seasonal Affective Disorder Version.

CONCLUSIONS

The beneficial effects of light therapy in the treatment of seasonal affective disorder are reversed by both tryptophan depletion and catecholamine depletion. These findings confirm previous work showing that serotonin plays an important role in the mechanism of action of light therapy and provide new evidence that brain catecholaminergic systems may also be involved.

Role of serotonin transporter promoter repeat length polymorphism (5-HTTLPR) in seasonality and seasonal affective disorder

Seasonal variations in mood and behavior (seasonality) and seasonal affective disorder (SAD) have been attributed to seasonal fluctuations in brain serotonin (5-HT). the short (s), as opposed to the long (l), allele of the 5-HT transporter linked polymorphism (5-HTTLPR) has been associated with neuroticism and depression. We hypothesized that this short allele would also be associated with SAD and with higher levels of seasonality. Ninety-seven SAD patients and 71 non-seasonal healthy controls with low seasonality levels were genotyped for 5-HTTLPR and compared statistically. Patients with SAD were less likely to have the l/l genotype (27.8% vs 47.9%; P < 0.01) and more likely to have the s allele (44.8% vs 32.4%; P < 0.02) as compared to controls. The three 5-HTTLPR genotypes were also differentially distributed in patients and controls (P < 0.03). The SAD patients with the l/l genotype had a lower mean seasonality score than did patients with the other two genotypes (mean +/- s.d. = 15.3 +/- 2.8 vs 17.1 +/- 3.4 respectively; P < 0.02). The 5-HTTLPR short allele contributes to the trait of seasonality and is a risk factor for SAD, providing further evidence for a relationship between genetic variation in the 5-HT transporter (5-HTT) and behavior.

Lack of seasonal variation of symptoms in patients with chronic fatigue syndrome

Several of the symptoms involved in chronic fatigue syndrome (CFS) such as fatigue, hypersomnia, hyperphagia, weight gain, and mood show seasonal variations in the general population. The aim of this study was to investigate whether patients with CFS experience seasonal fluctuations in these symptoms as well. Seasonal variation of symptoms was assessed in a group of 41 patients with CFS and 41 controls closely matched for age, gender, and city of residence. Participants were recruited across the US and were asked to complete the Seasonal Pattern Assessment Questionnaire (SPAQ) and the Profile of Mood States (POMS). CFS patients showed significantly lower scores on multiple SPAQ-derived measures as compared with controls. These included seasonal variation in energy, mood, appetite, weight, and sleep length. Patients also reported a significantly reduced sensitivity toward sunny, dry, and long days than controls. No association was noted between intensity of seasonal changes and severity of depressive symptoms. Patients with CFS exhibit an abnormally reduced seasonal variation in mood and behavior and would not be expected to benefit from light therapy.

Case series: pediatric seasonal affective disorder. A follow-up report

Six subjects who as children had received a diagnosis of seasonal affective disorder consented to participate in a 7-year follow-up study. Structured and semistructured interviews were conducted to assess the course of illness, response to treatment, and current clinical state. Seasonal patterns of symptoms and response to light therapy remained relatively stable over a 7-year period. Two subjects were using adjunctive fluoxetine. Seasonal affective disorder can occur in children and adolescents, responds to light therapy, and should be considered in the differential diagnosis of pediatric affective symptoms or cyclic school performance.

Effects of exogenous melatonin administration and withdrawal in five patients with rapid-cycling bipolar disorder

BACKGROUND

The ready availability of exogenous melatonin means that its use in patients with mood disorders is probably not uncommon. Nonetheless, few controlled trials of exogenous melatonin in these patients have been conducted.

METHOD

Five patients with rapid-cycling DSM-III-R bipolar disorder were treated with melatonin 10 mg q.d. at 10:00 p.m. for 12 weeks. Melatonin was added to a stable regimen of medication and administered in a double-blind, placebo-controlled fashion.

RESULTS

Melantonin administration had no positive effects. One patient developed a free-running (unentrained) sleep-wake cycle after melatonin withdrawal. In addition, in both this and a second patient, there is evidence that the administration of exogenous melatonin may have suppressed the secretion of endogenous melatonin.

CONCLUSION

The administration of melatonin had no significant effects on mood or sleep. However, melatonin withdrawal delayed sleep onset time and may have had some mild mood-elevating effects.

Seasonal variation in core temperature regulation during sleep in patients with winter seasonal affective disorder

Nocturnal core temperature during sleep is elevated during depression compared with remission in nonseasonally depressed patients. Similarly, nocturnal core temperature is higher during winter depression compared with remission induced by light treatment in seasonal affective disorder (SAD) patients. We investigated whether nocturnal core temperature in SAD patients naturally becomes lower in summer (during remission) compared with winter (during depression). Twenty-four-hour core temperature profiles were obtained in winter and summer in 22 SAD patients and 22 controls. The nocturnal core temperature minima were lower in summer compared with winter in SAD patients (p < .005), but not controls (p > .4). The seasonal changes in nocturnal core temperatures in SAD patients may reflect a unique physiological responsiveness of SAD patients to the change of seasons, and may be intimately related to the seasonal disturbances of mood and energy that are characteristic of SAD.

Seasonality and pituitary volume

Pituitary volume in humans has been reported to change size in response to experimental manipulations of photoperiod, and to be increased during an episode of non-seasonal major depression. We wanted to determine whether pituitary volume changes either across the seasons or during an episode of winter depression. Nineteen patients with winter-seasonal affective disorder and 19 sex-, age-, height-, and weight-matched controls underwent magnetic resonance imaging of the pituitary gland in both winter and summer. Images were obtained using 0.7-mm contiguous slices and the areas of all slices were summed to compute the final volume for each gland. We found no main effects or interactions involving either diagnosis or season in our primary analysis. In a post-hoc analysis, we found a trend towards a season x gender effect (P = 0.06), such that pituitary volume increased slightly (+4.0%) across seasons in women, whereas it decreased slightly (-4.3%) across seasons in men. The results suggest that neither winter depression nor the change of seasons is associated with a significant change in pituitary size.

A controlled trial of light therapy for the treatment of pediatric seasonal affective disorder

OBJECTIVE

To evaluate the efficacy of light therapy for the treatment of pediatric seasonal affective disorder (SAD).

METHOD

28 children (aged 7 to 17 years) at two geographically distinct sites were enrolled in a double-blind, placebo-controlled, crossover trial of bright-light treatment. Subjects initially entered a week-long baseline period during which they wore dark glasses for an hour a day. They were then randomly assigned to receive either active treatment (1 hour of bright-light therapy plus 2 hours of dawn simulation) or placebo (1 hour of clear goggles plus 5 minutes of low-intensity dawn simulation) for 1 week. The treatment phase was followed by a second dark-glasses phase lasting 1 to 2 weeks. After this phase, the children received the alternate treatment. Response was measured using the parent and child versions of the Structured Interview Guide for the Hamilton Depression Rating Scale, Seasonal Affective Disorders version (SIGH-SAD).

RESULTS

Data were analyzed as change from baseline. SIGH-SAD-P total depression scores were significantly decreased from baseline during light therapy compared with placebo (one-way analysis of variance, rho = .009), and no differences were found between the placebo and control phases. Subscores of atypical and typical depression were also significantly decreased during the active treatment (rho = .004 and .028, respectively). A similar trend was noted with the SIGH-SAD-C, but this did not reach significance. At the end of the study, 78% of the parents questioned and 80% of the children questioned rated light therapy as the phase during which the child "felt best."

CONCLUSION

Light therapy appears to be an effective treatment for pediatric SAD.

A naturally occurring amino acid substitution of the human serotonin 5-HT2A receptor influences amplitude and timing of intracellular calcium mobilization

Recently, two naturally occurring amino acid substitutions were identified in the C-terminal region of the serotonin 5-HT2A receptor. One of these, His452Tyr, has a rarer allele Tyr frequency of 9%. If 452Tyr alters 5-HT2A function, it would thus be a candidate allele for human neurobehavioral variation. The present study was designed to evaluate the potential influence of the 452His and 452Tyr alleles on cellular 5-HT2A functions. Platelet 5-HT2A binding and 5-HT-induced Ca2+ response were compared in eight 452His/452His homozygous and eight 452His/452Tyr heterozygous individuals matched for sex, age, and diagnosis (all were patients with seasonal affective disorder). There was no difference in 5-HT2A binding measured using 125I-lysergic acid diethylamide. Nor were levels of G-protein subunits or PKC alpha, delta, epsilon, or zeta significantly altered. However, when Ca2+ response was stimulated by 2, 5, 10, or 25 microM 5-HT, significant differences were found. In 452His/452Tyr heterozygotes, 452Tyr was associated with both smaller peak amplitude in Ca2+ mobilization and a different time course of response, with slower peak latency and longer half-time in 452His/452Tyr heterozygotes compared with 452His/452His homozygotes. The overall difference in the response of the 5-HT2A receptor in individuals with 452Tyr was a blunting of the shape of the Ca2+ mobilization peak. The data reported here suggest that the primary sequence of this intracellular domain is important in function of the receptor and that the 452His and 452Tyr 5-HT2A alleles should be carefully evaluated for effects on human neurobehavioral variation.

Effects of meta-chlorophenylpiperazine infusions in patients with seasonal affective disorder and healthy control subjects. Diurnal responses and nocturnal regulatory mechanisms

BACKGROUND

Multiple lines of evidence suggest that brain serotonergic systems may be disturbed in seasonal affective disorder (SAD). Previously, we found that the serotonergic agent meta-chlorophenylpiperazine (m-CPP) produced increases in activation and euphoria in depressed patients with SAD, but not in patients with SAD following light treatment or in the summer, nor in healthy control subjects in any condition. In the present study, we attempted to replicate and extend this finding using better methods.

METHODS

Seventeen outpatients with SAD and 15 control subjects underwent successive 3-week periods of bright light treatment and light avoidance in a randomized order. During the third week of each condition, on 2 different occasions, subjects were admitted to the hospital for a night of sleep (core temperatures were recorded), followed by infusions of m-CPP (0.08 mg/kg) or placebo the next morning. Dependent measures included the 24-item National Institute of Mental Health Self-Rating Scale, plasma corticotropin, cortisol, prolactin, growth hormone, and norepinephrine concentrations, and core temperatures.

RESULTS

Meta-chlorophenylpiperazine produced (1) significant increases in "activation-euphoria" ratings only in depressed patients with SAD in the untreated condition and (2) blunted corticotropin and norepinephrine responses in patients with SAD compared with controls across both light treatment conditions. In both groups, light treatment was associated with significant reductions in nocturnal core temperatures, which were correlated with similarly significant reductions in mean diurnal growth hormone concentrations. In patients with SAD, (1) the reductions in nocturnal core temperatures also were correlated with the reductions in baseline depression ratings and (2) the reductions in mean growth hormone concentrations were significantly smaller compared with controls.

CONCLUSIONS

The abnormal m-CPP-induced activation-euphoria responses represent a replicated state marker of winter depression in patients with SAD. The blunted m-CPP-induced responsiveness of the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system may represent traitlike abnormalities. The improvements in mood following light treatment in patients with SAD seem to be associated with the lowering of nocturnal core temperatures. The findings, although not easily explained based on a uniform abnormality of serotonin receptors, are nonetheless compatible with the notion that selected regions of the central nervous system are deficient in serotonin transmission during winter depression.

Two naturally occurring amino acid substitutions of the 5-HT2A receptor: similar prevalence in patients with seasonal affective disorder and controls

We screened the 5-HT2A receptor gene coding region in 50 patients with seasonal affective disorder (SAD) using a single strand conformational polymorphism analysis and estimated the frequencies of two synonymous and two non-synonymous substitutions we detected in 70 Centre d'Etude du Polymorphism Humain (CEPH) population controls and 62 normal controls. Both of the amino acid substitutions: Ala447-Val447 and His452-Tyr452, were located within the cytoplasmic. C-terminal tail of the receptor. Rarer allele frequencies in CEPH were 0.7% and 9.3% for Val447 and Tyr452, respectively. Allele frequencies of all four polymorphisms, including the two amino acid substitutions, were not significantly different in SAD patients as compared to CEPH and normal controls. Lack of association of Val447 and Tyr452 to SAD is consistent with observations showing normal 5-HT2A receptor Ca2+ response in platelets with this disorder, however, the two 5-HT2A amino acid substitutions may lead to differences in behavioral phenotypes.

Subsyndromal seasonal affective disorder in Antarctica

The seasonality of depressed mood was examined in 70 men and women who spent the 1991 austral winter at three American research stations in Antarctica. Seasonal Pattern Assessment Questionnaire global seasonality scores increased significantly from late summer (February/March) to midwinter (July/August; p < .001). Only one case of seasonal affective disorder (SAD) was found during midwinter, but the prevalence of subsyndromal SAD increased significantly, from 10.5 to 28.4 per 100, during this period. Station latitude was significantly associated with SAD-specific symptoms and global Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorders Version scores in midwinter and in early spring (October). The results suggest that even clinically normal individuals are likely to experience symptoms of subsyndromal SAD in high latitude environments, that these variations become more pronounced with increasing latitude, and that they can be detected through repeated administrations of instruments such as the Seasonal Pattern Assessment Questionnaire and Structured Interview Guide for the Hamilton Depression Rating Scale-Seasonal Affective Disorders Version.

Winter seasonal affective disorder: a follow-up study of the first 59 patients of the National Institute of Mental Health Seasonal Studies Program

OBJECTIVE

The purpose of this study was to characterize the long-term course of patients with seasonal affective disorder.

METHOD

The first 59 patients with winter seasonal affective disorder who had entered winter protocols were retrospectively followed up after a mean interval of 8.8 years. Detailed life charts were constructed through use of a semistructured interview and collateral records.

RESULTS

The disorder of 25 patients (42%) remained purely seasonal, with regular recurrences of winter depression and no depression or treatment through any summer. The course of illness was complicated by varying degrees of nonseasonal depression in 26 patients (44%). The disorders of eight patients (14%) had fully remitted. Certain features of the group with complicated seasonal affective disorder suggested that they were more severely ill. Twenty-four patients (41%) continued to use light treatment regularly throughout the follow-up period. Light treatment was preferred to medication for winter recurrences, although antidepressants had been used in the winter by most (63%) of the patients who still used lights at follow-up.

CONCLUSIONS

The pattern of winter depressions and summer remissions remained fairly persistent over time in this group of patients. The temporal distribution of depressive episodes both within and across individual patients was consistent with the results of several recent follow-up studies of seasonal affective disorder, providing support for the predictive and construct validity of the Rosenthal et al. diagnosis of winter seasonal affective disorder. Light treatment, while remaining a safe and satisfactory treatment for many, may be insufficient for more severely ill patients. The appearance of nonseasonal depressions in patients with winter seasonal affective disorder may be associated with greater severity of illness and less responsiveness to light treatment.

Relationship between sleep and mood in patients with rapid-cycling bipolar disorder

The relationship between sleep and mood was examined in a longitudinal, naturalistic data set derived from out-patients with rapid-cycling bipolar disorder. Eleven patients completed daily self-ratings of mood and sleep logs for 18 months. Using logistic regression with autoregressive terms, we examined the effect of prior sleep (sleep duration, time of sleep onset, and time of wake onset) on the probability of being in a depressed, manic, or hypomanic episode on one or more subsequent days. Of the three sleep parameters, decreased sleep duration was the best predictor of mania or hypomania the next day, followed by wake onset time. The association between sleep duration and subsequent mood was less consistent for depression than for mania or hypomania. Four of the patients showed no relationship between mood and any of the sleep variables measured. These results reinforce the importance of monitoring, and perhaps controlling, sleep duration and wake onset time in at least some patients with rapid-cycling bipolar disorder.

Circadian profiles of cortisol, prolactin, and thyrotropin in seasonal affective disorder

To determine whether circadian profiles of various plasma hormones are abnormal in patients with winter seasonal affective disorder (SAD), we obtained 24-hour profiles of plasma cortisol, prolactin, and thyrotropin in subsets of a sample of 22 depressed patients with SAD on and off light therapy and in subsets of a sample of 24 normal controls. Cortisol levels did not differ between patients and controls, and levels in patients were not affected by light therapy. Prolactin levels were lower in patients than in controls throughout the day (p < 0.03) but were unaffected by light therapy. Independent of patient vs. control status, prolactin levels were higher in women than in men throughout the day (p < 0.003). Thyrotropin levels were no different in patients and controls, but levels in patients were lower following light therapy (p < 0.05).

Seasonal changes in mood and behavior. The role of genetic factors

BACKGROUND

Seasonal rhythms in mood and behavior (seasonality) have been reported to occur in the general population. Seasonal affective disorder, a clinically diagnosed syndrome, is believed to represent the morbid extreme of a spectrum of seasonality. Two types of seasonality have been clinically described: one characterized by a winter pattern and a second by a summer pattern of depressive mood disturbance.

METHODS

By using methods of univariate and multivariate genetic analysis, we examined the relative contribution of genetic and environmental factors to the risk of seasonality symptoms that were assessed by a mailed questionnaire of 4639 adult twins from a volunteer-based registry in Australia.

RESULTS

Seasonality was associated with a winter rather than a summer pattern of mood and behavioral change. In each behavioral domain (ie, mood, energy, social activity, sleep, appetite, and weight), a significant genetic influence on the reporting of seasonal changes was found. Consistent with the hypothesis of a seasonal syndrome, genetic effects were found to exert a global influence across all behavioral changes, accounting for at least 29% of the variance in seasonality in men and women.

CONCLUSIONS

There is a tendency for seasonal changes in mood and behavior to run in families, especially seasonality of the winter type, and this is largely due to a biological predisposition. These findings support continuing efforts to understand the role of seasonality in the development of mood disorders.

Effects of season on electro-oculographic ratio in winter seasonal affective disorder

Low electro-oculographic (EOG) ratios have been reported in patients with seasonal affective disorder (SAD) during the winter. This study evaluated the effects of the changing seasons on EOG ratios in SAD patients. Sixteen outpatients with SAD and 16 age-, sex-, and medication-matched normal volunteers had EOG testing during the winter and again during the summer. There was a significant season x group interaction in EOG ratios, with normal subjects showing higher ratios in winter than in summer--a seasonal variation not observed in SAD patients. SAD patients may have a subsensitivity to environmental light that leads them to experience symptoms during the winter.

Serotonin and thermoregulation. Physiologic and pharmacologic aspects of control revealed by intravenous m-CPP in normal human subjects

Meta-chlorophenylpiperazine (m-CPP), a probe of central serotonergic function, elevates core temperature in rodents, nonhuman primates, and humans via serotonin receptor-mediated mechanisms. To further characterize the thermoregulatory aspects of this response, we studied 16 healthy volunteers using multiple core and skin temperature recording sites. Compared to placebo, intravenous m-CPP (0.08 mg/kg) produced statistically significant biphasic changes in rectal temperature, characterized by initial hypothermia (-0.04 degrees C at 12 minutes) followed by progressive hyperthermia (+0.17 degrees C at 90 minutes). m-CPP also produced significant increases in plasma norepinephrine concentrations. Analysis of the skin temperature recordings suggests that the effector mechanism primarily responsible for m-CPP-induced core hyperthermia is increased metabolic thermogenesis. Individual differences in the magnitude of the hyperthermia were independent of m-CPP plasma concentrations but were found to be linearly correlated with the level of the previous night's core rectal temperature minimum and mean. It appears that m-CPP activates a mode of metabolic thermogenesis governed by a nocturnally sensitive proportional control mechanism. The operation of such a proportional controller is characterized by a set point and a gain, and has been implicated in the general economy of mammalian energy balance.