Letters to the Editor
Posttraumatic Mood Disorder: A New Concept
Dear Editor:
A recent study found that comorbidity of posttraumatic stress disorder (PTSD) and depression was associated with global psychosocial impairment, distress, social impairment, and occupational disability and that this distinction remained when the comorbid group was compared directly with a pure PTSD group (1). These findings raised the question whether comorbid PTSD and depression should be recognized as a core posttraumatic affective disorder.
Neurobiological findings support the notion that posttraumatic mood disorder can be recognized as a separate disorder. Maes and others reported an association between PTSD with concurrent major depression and lower affinity of alpha 2 adrenoreceptors, as well as higher plasma tyrosine availability to the brain, not found in patients suffering from PTSD alone (2). This indicates that monoaminergic mechanisms may play a role in the pathophysiology of comorbid PTSD and depression. Woodward and others found that patients with comorbid PTSD and depression exhibited less slow wave sleep and less facial (mentalis) electromyographic activity, compared with PTSD patients without comorbid depression (3).
Cortisol response to placebo or fenfluramine was examined in depression patients with or without comorbid PTSD and in a control group of healthy volunteers (4). Depression patients with comorbid PTSD had the lowest plasma cortisol; depression patients without comorbid PTSD had the highest plasma cortisol; and healthy volunteers had intermediate levels. Sher and others compared the effect of age on postchallenge cortisol levels in depression patients with or without comorbid PTSD and in healthy volunteers (5). We found that cortisol levels increased with age in depression patients with PTSD alone; they did not increase in depression patients with comorbid PTSD or in healthy volunteers. Family studies suggest a shared liability for PTSD and major depression, with familial loading for major depression predicting chronic PTSD in trauma survivors (6). Future studies of comorbid PTSD and depression should include large samples, independent ratings of exposure severity, ratings of psychological health done independently of exposure, reliable information on the timing of the disorders’ onset and offset, and measures of putative biological markers (7). Studies of comorbid PTSD and depression may produce important results.
References
1. Momartin S, Silove D, Manicavasagar V, Steel Z. Comorbidity of PTSD and depression: association with trauma exposure, symptom severity and functional impairment in Bosnian refugees resettled in Australia. J Affect Disord 2004;80:231–48.
2. Maes M, Lin AH, Verkerk R, Delmeire L, Van Gastel A, Van der Planken M, and others. Serotonergic and noradrenergic markers of post-traumatic stress disorder with and without major depression. Neuropsychopharmacology 1999;20:188–97.
3. Woodward SH, Friedman MJ, Bliwise DL. Sleep and depression in combat-related PTSD inpatients. Biol Psychiatry 1996;39:182–92.
4. Oquendo MA, Echavarria G, Galfalvy HC, Grunebaum MF, Burke A, Barrera A, and others. Lower cortisol levels in depressed patients with comorbid post-traumatic stress disorder. Neuropsychopharmacology 2003;28:591–8.
5. Sher L, Oquendo MA, Galfalvy HC, Cooper TB, Mann JJ. Age effects on cortisol levels in depressed patients with and without comorbid posttraumatic stress disorder, and healthy volunteers. J Affect Disord 2004;82:53–9.
6. Davidson JR, Tupler LA, Wilson WH, Connor KM. A family study of chronic post-traumatic stress disorder following rape trauma. J Psychiatr Res 1998;32:301–9.
7. Neria Y, Bromet EJ. Comorbidity of PTSD and depression: linked or separate incidence. Biol Psychiatry 2000;48:878–80.
Leo Sher, MD
New York, New York
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