The Immunological Alterations in Major Depression Are Not Caused by Antidepressant Medication




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