Effects of light on low nocturnal bilirubin in winter depression: a preliminary report.
BACKGROUND
The light-absorbing pigments involved in the induction of treatment of winter depression are unknown. It has been proposed that circulating bilirubin serves as a photoreceptor, in part because of its similarity to the chromophore of phytochrome, a primary time-setting plant molecule.


METHODS
We measured nocturnal bilirubin levels in nine patients with winter depression, and seven age- and gender-matched normal comparison volunteers.


RESULTS
Nocturnal bilirubin levels were lower in patients than in controls (p <.02), increased in both groups during the night (p <.0001), and increased in patients after 2 weeks of morning light treatment (p =.0009), which was accompanied by clinical improvement.


CONCLUSIONS
Low nocturnal bilirubin levels may be associated with winter seasonal depression.
Oren
Dan A
DA
VA Connecticut Healthcare System and Yale School of Medicine, Department of Psychiatry, West Haven, CT 06516, USA.
Desan
Paul H
PH
Boutros
Nashaat
N
Anand
Amit
A
Charney
Dennis S
DS
D000328:Adult; D001663:Bilirubin / Q000097:blood*; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010789:Phototherapy; D016574:Seasonal Affective Disorder / Q000097:blood / Q000628:therapy*; D016896:Treatment Outcome
D001663:Bilirubin