Seasonal variation in mood and behavior was examined in 87 American men and
women who spent the 1991 austral winter at three different research statio
ns in Antarctica. The South Pole station (90 degrees S) crew reported a sig
nificant decline in tension/anxiety, depression, anger, confusion, and fati
gue from March to August, followed by a significant increase in tension/anx
iety and fatigue and a significant decline in vigor from August to October.
The McMurdo station (78 degrees 51 ' S) crew also reported a significant d
ecline in tension/anxiety from March to July and a significant increase in
tension/anxiety from Jury to August. In contrast, the Palmer station (64 de
grees 46' S) crew experienced no significant changes in any mood subscale f
rom May to October. The nonlinear pattern of change in mood suggests that a
daptation to prolonged isolation and confinement in an extreme environment
occurs in two or three stages.