THE IMMUNOLOGICAL ALTERATIONS IN MAJOR
DEPRESSION ARE NOT CAUSED BY ANTIDEPRESSANT MEDICATION
Marion
Peters*, Matthias Rothermundt, Volker Arolt and Holger
Kirchner. University of Lübeck, Germany
Immune dysfunction as one
possible factor in the pathogenesis of depression has been
under investigation for two decades. Altered numbers of
immunocompetent cells and their activity as well as changes
in cytokine or acute phase protein production have been
demonstrated. Most reported results point into the direction
of immune activation in the acute clinical state of major
depression. One major confounding variable of these results
is psychotropic medication. Several in vitro and in vivo
investigations have lead to conflicting results.
In order to investigate
possible medication effects on the immunological changes in
major depression we conducted a study on 39 inpatients
suffering from major depression over a period of 6 weeks. 16
patients received antidepressant medication plus
psychotherapeutic treatment while 23 patients were treated
only by psychotherapy. The patients were immunologically and
psychiatrically investigated on admission, after 2, 4, and 6
weeks of treatment. The results were compared with those of
age and sex matched healthy controls.
On admission the counts of
monocytes and natural killer cells in depressed patients were
significantly increased. After 6 weeks of treatment they
approached the counts of the healthy controls. The production
of interferon gamma upon mitogen stimulation and the levels
of the soluble IL-2 receptor in the supernatants were also
significantly increased on admission compared to healthy
controls. These results of the whole group of depressed
patients were also found in medicated and unmedicated
subgroups. No significant differences concerning demographic
data, psychopathology and immunological functions between
both subgroups were observed.
In this study we were able to
reproduce the reported immunological findings in major
depression. Since these immunological changes are present in
medicated as well as unmedicated depressed patients it is
unlikely that they are caused by psychotrophic medication.
They rather may represent an altered immune function in major
depression that may play a role in the pathogenesis of the
disease.