Letters to the Editor
Reply: Evidence Supports Validity of Seasonal Affective Disorder
Dear Editor:
Let me thank Dr Michalak and Dr Lam for bringing to our attention an issue
of major clinical importance—seasonal affective disorder (SAD). To illustrate
the potential significance of such a disorder: if it were proven to recur
consistently in the same season it could be treated intermittently, without
exposing patients to the well-known adverse effects of chronic pharmacotherapy.
Dr Michalak and Dr Lam express surprise that I do not share their belief
in SAD as a distinct subtype. The reason is simple, as I mentioned in my
editorial: “In clinical course, genetic, and treatment studies, there is
still no convincing justification” (1, p 124) for such an entity—and I
am in good company when I conclude that SAD remains an elusive fiction
(2,3).
A striking seasonality of episode onsets certainly exists for groups of
patients with mood disorders, but individuals who experience recurrences
in the same season for a few years lose this pattern later. The database
from an international study of 1309 patients, developed and published before
the present enchantment with SAD, shows that individual patients do not
experience recurrences in the same season more often than might be expected
by chance (4). Further, there is not a single patient in the study with
recurrences continuing in the same season over the lifetime. Studies demonstrating
that patients who initially meet the SAD criteria continue meeting them
over time, are also missing in the literature.
To defend their belief, Dr Michalak and Dr Lam refer to what they consider
to be indisputable authorities: the DSM-IV (5) and the International Guidelines
(6). However, the DSM-IV committees refused to recognize SAD as an entity,
politely downgrading it to a simple “qualifier.” When I questioned Dr M
Bauer, chair of the group that produced the International Guidelines, about
the 2-paragraph statement on SAD, he wrote that the statement was based
exclusively on “a review of literature, not on investigation.” Interestingly,
the Guidelines’ authoritative literature turns out to be a couple of papers
by none other than Dr Lam himself.
I agree with Dr Michalak and Dr Lam on 2 points. First, I agree that light
therapy works—but it is similarly helpful in nonseasonal mood disorders
(7), and some medications, such as tranylcypromin, work even better in
reputed cases of SAD. Second, I agree that a large number of articles have
indeed been published about SAD—but frequent repetition alone does not
make the disorder real. In fact, that’s how myths have often been created
in psychiatry: consider, for example, the extensive earlier literature
on entities such as “involutional melancholia” and “anniversary depression”
(the psychoanalytic precursor of SAD). Without evidence, such entities
sooner or later become history.
I have collected lifetime data on the clinical course of nearly 2000 patients
with mood disorders, and I have approached 2 colleagues who claim to specialize
in SAD, yet I still have not come across a single patient with several
recurrences limited mostly to a particular season. If Dr Michalak and Dr
Lam have at least a couple of patients who actually continue meeting the
criteria for SAD for an extended period, I would be happy to interview
the patients and publicly recant my solid skepticism about SAD.
References
1. Grof P. Mood disorders—new definitions, treatment, directions, and understanding
[editorial]. Can J Psychiatry 2002;47:123–4.
2. Eastwood MR, Peter AM. Epidemiology and seasonal affective disorder
[editorial]. Psychol Med 1988;18:799–806.
3. Van Praag HM. “Make-believes” in psychiatry. New York: Brunner-Mazel;
1993.
4. Angst J, Baastrup PC, Grof P, Hippius H, Poldinger W, Weiss P. Clinical
course of affective disorders. Psychiatry 1973;76:489–500.
5. American Psychiatric Association. Diagnostic and statistical manual
of mental disorders. 4th ed. Washington (DC): American Psychiatric Association;
1994.
6. Bauer M, Whybrow PC, Angst J, Versiani M, Moller H-J. World Federation
of Societies of Biological Psychiatry (WFSBP) guidelines for biological
treatment of unipolar depressive disorders, part 1: acute and continuation
treatment of major depressive disorder. World Journal of Biological Psychiatry
2002;3:5–43.
7. Kripke DF. Light treatment for nonseasonal major depression: are we
ready? In: Lam RW, editor. Seasonal affective disorder and beyond. Washington
(DC): American Psychiatric Press; 1998. p 159–72.
Paul Grof, MD, FRCPC
Ottawa, Ontario
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