Recent systematic review s have shown that  light therapy  is an efficacious and well-tolerated treatment for SAD .
There is also evidence for efficacy of pharmacotherapy to treat and prevent SAD .
SAD is a common condition with significant psychosocial impairment .
BACKGROUND Seasonal affective disorder ( SAD ) consists of recurrent major depressive episodes in the fall/winter with remissions in spring/summer .
RESULTS A careful history is important to make the diagnosis and differentiate SAD from other similar conditions such as subsyndromal SAD and atypical depression .
Seasonal patterns with winter worsening are also recognized in " nonseasonal " depression as well as many other psychiatric conditions , and comorbidity with SAD is common .
The pathophysiology of SAD seems to be heterogeneous as research on circadian , neurotransmitter function and genetic hypotheses have shown discrepant results .
A dual vulnerability model with differential loading on separate seasonal and depression factors has been proposed to explain these findings .
Multicenter, placebo-controlled study of fluoxetine in seasonal affective disorder.
OBJECTIVE The authors investigated the efficacy and safety of fluoxetine in the treatment of winter seasonal affective disorder . METHOD Sixty-eight out patients who met the DSM-III-R criteria for recurrent major depressive episodes , seasonal ( winter ) pattern , were r and omly assigned to 5 weeks of treatment with fluoxetine , 20 mg/day ( N = 36 ) , or placebo ( N = 32 ) . The outcome measures included the 29-item modified Hamilton Depression Rating Scale , administered by experienced clinicians , and the self-rated Beck Depression Inventory ; adverse events and safety data were also recorded . Clinical response was defined as a greater than 50 % reduction in depression score between baseline and study termination . RESULTS Both groups showed significant improvement . The fluoxetine group had lower depression scores at termination than the placebo group , but these differences did not achieve statistical significance . However , the rate of clinical response in the fluoxetine group ( 59 % ) was superior to that in the placebo group ( 34 % ) . Post hoc analyses showed that the greatest fluoxetine responses were in the most markedly depressed patients and that overall response was greater for patients studied later in the season . Fluoxetine was well tolerated , and few subjects dropped out because of adverse events . CONCLUSIONS On the basis of clinical response rate , fluoxetine appears to be an effective , well-tolerated treatment for seasonal affective disorder . Because the differences between fluoxetine and placebo in the continuous outcome measures did not reach statistical significance , further studies with larger study groups and longer treatment periods are required to conclusively demonstrate efficacy of fluoxetine for seasonal affective disorder
Recent systematic review s have shown that  light therapy  is an efficacious and well-tolerated treatment for SAD .
There is also evidence for efficacy of pharmacotherapy to treat and prevent SAD .
SAD is a common condition with significant psychosocial impairment .
BACKGROUND Seasonal affective disorder ( SAD ) consists of recurrent major depressive episodes in the fall/winter with remissions in spring/summer .
RESULTS A careful history is important to make the diagnosis and differentiate SAD from other similar conditions such as subsyndromal SAD and atypical depression .
Seasonal patterns with winter worsening are also recognized in " nonseasonal " depression as well as many other psychiatric conditions , and comorbidity with SAD is common .
The pathophysiology of SAD seems to be heterogeneous as research on circadian , neurotransmitter function and genetic hypotheses have shown discrepant results .
A dual vulnerability model with differential loading on separate seasonal and depression factors has been proposed to explain these findings .