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.

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Effects of Tryptophan Depletion on Drug-Free Patients With Seasonal Affective Disorder During a Stable Response to Bright Light Therapy

Archives of General Psychiatry ◽

10.1001/archpsyc.1997.01830140043008 ◽

1997 ◽

Vol 54 (2) ◽

pp. 133 ◽

Cited By ~ 80

Author(s):

Alexander Neumeister

Keyword(s):

Affective Disorder ◽

Seasonal Affective Disorder ◽

Bright Light ◽

Light Therapy ◽

Tryptophan Depletion ◽

Bright Light Therapy ◽

Drug Free

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Melatonine en stemmingsstoornissen

Acta Neuropsychiatrica ◽

10.1017/s0924270800037376 ◽

1995 ◽

Vol 7 (3) ◽

pp. 75-79

Author(s):

J. Beullens

Keyword(s):

Pineal Gland ◽

Affective Disorder ◽

Premenstrual Syndrome ◽

Affective Disorders ◽

Seasonal Affective Disorder ◽

Bright Light ◽

Light Therapy ◽

Melatonin Level ◽

Melatonin Secretion ◽

The Relationship

SummaryMelatonin is a hormone secreted by the pineal gland mainly during the night. The discovery that this melatonin secretion decreases under the influence of bright light, gave rise to the use of light therapy in some affective disorders. The literature on the relationship between melatonin secretion and mood is reviewed concerning seasonal affective disorder, non-seasonal affective disorder and premenstrual syndrome. Light therapy could reduce an abnormal high melatonin secretion back to normal proportions. None of the affective disorders, however, is accompanied by an unusual high melatonin level. Nevertheless, light therapy as well as other therapies that suppress melatonin have a therapeutic effect. This is not the case with the administration of melatonin. Mood is not affected by extra melatonin in seasonal affective disorder but it is in both other affective disorders. Melatonin plays a part in the pathogenesis of the affective disorders but it is not yet clear which one.

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The Diagnosis, Symptomatology, and Epidemiology of Seasonal Affective Disorder

CNS Spectrums ◽

10.1017/s1092852900019593 ◽

2005 ◽

Vol 10 (8) ◽

pp. 625-634 ◽

Cited By ~ 99

Author(s):

Andres Magnusson ◽

Timo Partonen

Keyword(s):

Affective Disorder ◽

Seasonal Affective Disorder ◽

Bright Light ◽

Light Therapy ◽

International Classification Of Diseases ◽

Emotional Symptoms ◽

Diagnostic And Statistical Manual ◽

Northern Latitudes ◽

Classification Of Diseases ◽

Operational Criteria

AbstractThe operational criteria for seasonal affective disorder (SAD) have undergone several changes since first proposed in 1984. SAD is currently included as a specifier of either bipolar or recurrent major depressive disorder in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. The International Classification of Diseases, Tenth Edition has provisional diagnostic criteria for SAD. The most characteristic quality of SAD is that the symptoms usually present during winter and remit in the spring. Furthermore, the symptoms tend to remit when the patients are exposed to daylight or bright light therapy. The cognitive and emotional symptoms are as in other types of depression but the vegetative symptoms are the reverse of classic depressive vegetative symptoms, namely increased sleep and increased appetite. SAD is a common condition, but the exact prevalence rates vary between different studies and countries and is consistently found to be more common in women and in youth. SAD probably possibly occurs in children although not as commonly as in young adults. Some studies have found that certain ethnic groups who live at high northern latitudes may have adapted to the long arctic winter.

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