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 .
Bright light therapy: side effects and benefits across the symptom spectrum.
BACKGROUND Bright light therapy has been established for treatment of winter depression , or seasonal affective disorder ( SAD ) . Analysis of side effects most often have focused on a narrow set of suspected symptoms , based on clinical observation ( e.g. , headache , eyestrain , nausea , insomnia , and hyperactivity ) . This study broadens the purview to a set of 88 physical and subjective symptoms that might emerge , remit , or remain unchanged relative to baseline , thus reducing bias toward assessment of presumed side effects . METHOD Eighty-three patients with SAD ( DSM-III-R criteria for mood disorders with seasonal pattern [ winter type ] and National Institute of Mental Health criteria for SAD ) received bright light therapy at 10,000 lux for 30 minutes daily in the morning or evening for 10 to 14 days . They completed a question naire ( Systematic Assessment for Treatment Emergent Effects ) , rating symptom severity before and after treatment . Results were compared for morning or evening treatment and for responders and nonresponders . RESULTS Several side effects emerged -- mostly mildly -- including jumpiness/jitteriness ( 8.8 % ) , headache ( 8.4 % ) , and nausea ( 15.9 % ) , mirroring findings of past studies with a less inclusive scope . In most cases , remission rate equalled or exceeded emergence rate . Several nondepressive symptoms also showed large improvement , including poor vision and skin rash/itch/irritation . Being overactive/excited/elated showed greater emergence under morning light and greater remission under evening light . Emergence of nausea was greater than remission in responders . CONCLUSION The dominant effect of light treatment was improvement in bothersome symptoms . Although patients should be advised of side effects and guided in dose manipulations to reduce them , attention also should be drawn to the substantial benefit-to-risk ratio . Improvement of symptoms outside the depressive cluster , seen in both responders and nonresponders , may point to new therapeutic uses of light therapy
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 .