Patients with seasonal affective disorder have lower odor detection thresholds than control subjects.
BACKGROUND
Behavioral changes in patients with seasonal affective disorder resemble seasonal changes in photoperiodic animals. Because the olfactory system has a modulatory role in seasonal photoperiodic responses in certain species, we hypothesized that olfactory function may differ between patients with seasonal affective disorder and healthy control subjects.


METHODS
Fourteen patients who had winter seasonal affective disorder and 16 healthy volunteers were studied once in winter and once in the subsequent summer. We administered a phenyl ethyl alcohol detection threshold test to each side of the nose in a counterbalanced order, with the nostril contralateral to the tested site occluded. Patient and control data were compared using a 4-way repeated measure analysis of covariance (with group and gender as between-subjects factors, season and side-of-the-nose as within-subjects factors, and age as a covariate).


RESULTS
The patients exhibited lower thresholds than did the controls (F(1,25) = 9.2; P =.006). There was no main effect of season.


CONCLUSIONS
In humans, marked seasonal behavioral rhythms with recurrent winter depression may be associated with a more acute sense of smell.
Postolache
Teodor T
TT
Section on Biological Rhythms, National Institute of Mental Health/NIH, 10 Center Dr, Room 3S-231, Bethesda, MD 20892, USA. postolache@nih.gov
Wehr
Thomas A
TA
Doty
Richard L
RL
Sher
Leo
L
Turner
Erick H
EH
Bartko
John J
JJ
Rosenthal
Norman E
NE
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010555:Personality Inventory; D012016:Reference Values; D016574:Seasonal Affective Disorder / Q000175:diagnosis* / Q000523:psychology; D012684:Sensory Thresholds; D012903:Smell