Melatonin Sensitivity to Dim White Light in Affective Disorders

• Published in: Neuropsychopharmacology (New York, N.Y.) Vol. 21; no. 3; pp. 408 - 413
• Main Authors: Nathan, Pradeep J, Burrows, Graham D, Norman, Trevor R
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.09.1999; Nature Publishing
• Subjects: Adolescent; Adult; Adult and adolescent clinical studies; Affective disorders; Aged; Biological and medical sciences; Biological marker; Biomarkers - blood; Bipolar Disorder - blood; Bipolar disorders; Circadian rhythms; Depression; Depressive Disorder, Major - blood; Dim-light; Humans; Light; Light-sensitivity; Medical sciences; Melatonin; Melatonin - blood; Middle Aged; Mood disorders; Mood Disorders - blood; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Seasonal Affective Disorder - blood; Suppression; Circadian rhythms; Melatonin; Affective disorders; Suppression; Biological marker; Light-sensitivity; Dim-light; Mood disorder; Human; Affective disorder; Night; Light; Bipolar disorder; Sensitization; Circadian rhythm; Light stimulus; Pineal hormone
• ISSN: 0893-133X; 1740-634X
• DOI: 10.1016/S0893-133X(99)00018-4

Both dim and bright light has been shown to suppress the nocturnal secretion of the pineal hormone melatonin. Early reports suggests that an abnormal response to light occurs in patients with bipolar affective disorder, where as patients with major depressive disorder respond similarly to controls. It has been suggested that this abnormal sensitivity of the melatonin response to light could be a trait marker of bipolar affective disorder. However reports lack consistency. Hence, we investigated the melatonin suppression by dim light (200 lux) in patients with bipolar affective disorder, seasonal affective disorder and major depressive disorder. Results suggest that a supersensitive melatonin suppression to light in bipolar affective disorder (p < .005), and seasonal affective disorder (p < .05), whereas patients with major depressive disorder display similar suppression to controls. The supersensitivity may be a mechanism where by phase-delayed rhythms, are re-synchronised to a new circadian position. Conversely, an abnormality may exist in the pathway from the retina to the suprachiamatic nucleus.