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 .
Effects of fluoxetine versus bright light in the treatment of seasonal affective disorder.
BACKGROUND Disturbances of serotonergic neurotransmission appear to be particularly important for the pathophysiology of winter depression . This study investigated whether fluoxetine has antidepressant effects comparable to bright light in the treatment of seasonal affective disorder ( winter type ) . METHOD A r and omized , parallel design was used with rater and patients blind to treatment conditions . One week of placebo ( phase I ) was followed by 5 weeks of treatment ( phase II ) with fluoxetine ( 20 mg per day ) and a placebo light condition versus bright light ( 3000 lux , 2 h per day ) and a placebo drug . There were 40 patients ( 20 in each treatment condition ) suffering from seasonal affective disorder ( SAD ) according to DSM-III-R who had a total score on the Hamilton Depression Scale of at least 16 . RESULTS Forty patients entered phase II and 35 completed it ( one drop-out in the fluoxetine group and four in the bright light group ) . Fourteen ( 70 % ) of the patients treated with bright light and 13 ( 65 % ) of those treated with fluoxetine were responders ( NS ) . The remission rate in the bright light group tended to be superior ( bright light 50 % , fluoxetine 25 % ; P = 0.10 ) . Light therapy  improved HDRS scores significantly faster , while fluoxetine had a faster effect on atypical symptoms . Light treatment in the morning produced a significantly faster onset of improvement , but at the end of treatment the time of light application seemed not to be crucial . CONCLUSION Both treatments produced a good antidepressant effect and were well tolerated . An apparently better response to bright light requires confirmation in a larger sample
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 .