Vol 5 n° 4 - Chronobiology and Mood Disorders
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easonal affective disorder (SAD), as originally described in 1984,1 is a condition characterized by the annual recurrence of depressive episodes in fall and win- ter followed by remission of depressive symptoms in spring and summer.1 Patients with SAD have to meet diagnostic criteria for major depression, recurrent, or bipolar disorder. In the latest version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), SAD is listed as a specifier of either bipolar or recurrent major depressive disorder, with a seasonal pattern of major depressive episodes.2 Subsyndromal SAD is a dis- order  with  similar  but  milder  symptoms  that  do  not grossly disrupt patients social and occupational func- tioning.3 The four central features characterizing SAD are listed in Table I. Patients with SAD have the usual symptoms of depression, including low mood, lack of drive, decreased concentration, and reduced interest. Typically, many SAD patients also tend to have a specific symptom cluster consisting of the so-called reverse veg- etative or atypical depressive symptoms.These symptoms include increased sleep (70%-90% of SAD patients), increased appetite (70%-80%), carbohydrate craving (80%-90%), and weight gain (70%-80%).4 Pathophysiology The etiology of SAD remains unclear. It is thought that the decreasing daylight period as winter approaches trig- gers  depressive  episodes  in  individuals  vulnerable  to SAD. However, although bright light exposure is used in the treatment of SAD, no causal relation can be drawn between the occurrence of SAD and the shortage of light in fall and winter. Patients with SAD may be sensitive to factors that are common to various forms of recurrent Keywords:   seasonal   affective   disorder;   depression;   light   therapy;   pharmacotherapy; treatment guidelines Author  affiliations:  Centre  for  Addiction  and  Mental  Health,  PET  Centre, Toronto, ON, Canada Address for correspondence: Nicole Praschak-Rieder, MD, Centre for Addiction and Mental Health, PET Centre, 250 College Street, Toronto, Ontario, Canada M5T 1R8 (e-mail: nicole@camhpet.on.ca) C l i n i c a l   r e s e a r c h 3 8 9 Treatment of seasonal affective disorders Nicole Praschak-Rieder, MD; Matthäus Willeit, MD S Seasonal affective disorder (SAD) is a subform of major depressive disorder, recurrent, or bipolar disorder with a regular onset of depressive episodes at a certain time of year, usually the winter. The treatment of SAD is similar to that of other forms of affective disorder, except that bright  light  therapy  is  recommended  as  the  first-line option. Light therapy conventionally involves exposure to visible light of at least 2500 lux intensity at eye level. The effects of light therapy are thought to be mediated exclu- sively by the eyes, not the skin, although this assumption has not yet been verified. Morning light therapy has proven  to  be  superior  to  treatment  regimens  in  the evening. Response rates to light therapy are about 80% in selected patient populations, with atypical depressive symptoms being the best predictor of a favorable treat- ment outcome. Data from randomized, controlled trials suggest that antidepressants are effective in the treat- ment of SAD. Three double-blind, placebo-controlled tri- als have been conducted showing promising results for the selective serotonin reuptake inhibitors (SSRIs) sertra- line  and  fluoxetine,  as  well  as  for  moclobemide,  a reversible inhibitor of monoamine oxidase A. © 2003, LLS SAS Dialogues Clin Neurosci. 2003;5:389-398. Copyright © 2003 LLS SAS.  All rights reserved www.dialogues-cns.org