The Role of Inflammatory Processes in Development and Treatment of Depression

The study investigates the influence of inflammatory processes on the development and the course of uni- and bipolar depression. It is assumed, that the concentrations of certain inflammatory proteins have an influence on the development of depression, its clinical severity, the response to treatment and the risk of relapse. To verify this hypothesis, a total of 145 patients, which were hospitalized für treatment of a depressive disorder in the study centers in Germany, Italy and France, were screened according to the criteria set out in the study protocol. Finally, 104 patients with moderate to severe depressive symptoms were included in the study. The severity of the symptoms was classified using well-established clinical rating scales like Montgomery-Asberg Depression Rating Scale (MADRS) and Hamilton rating scale for depression (HAMD). All enrolled patients were treated according to the recommendations of the German Association for Psychiatry, Psychotherapy and Psychosomatics (DGPPN) treatment guidelines.

In order to make drug-induced changes in the serum concentrations of the examined proteins as comparable as possible, it was determined in advance, that all patients should be treated with either sertraline (first choice) or venlafaxine (second choice) as an oral antidepressant. Apart from that, the antidepressive therapy, ie psychotherapy and similar procedures, had not been standardized. The treatment of study participants did not differ from the treatment of other patients hospitalized because of depression, who did not participate in the study. The patients were examined for the presence and severity of depressive symptoms at the time of study enrollment, as well as after 4 and 8 weeks, using standardized clinical test procedures. In addition blood was taken. In the serum of the patients, the concentrations of specific inflammatory proteins were measured using Cytometric Bead Array (CBA) and Enzyme-linked Immunosorbent Assay (ELISA) and then correlated with the clinical data. The investigated proteins include high-sensitivity CRP (C-Reactive-Protein), Interleukin 4, Interleukin 6, Interleukin 12, tumor necrosis factor-α, Eotaxin, Intercellular adhesion molecule 1 (CD54), Interferone-gamma and monocyte chemotactic protein 1 (MCP-1).

Inclusion criteria

• Patients with uni- or bipolar depression, diagnosed according to the criteria of the Diagnostic and Statistical Manual Version IV (DSM-IV) via Mini-international neuropsychiatric interview Version 6.0 (MINI 6.0) diagnostic tool.
• At the time of inclusion in the study, the symptoms must meet at least the requirements of a moderately severe depression, defined by a minimum score of ≥ 22 on the Montgomery-Asberg Depression Scale.

Exclusion criteria

• Patients with severe somatic, rheumatic, endocrine or neurological comorbidities. This includes in particular neurological disorders associated with cognitive disorder, severe liver, kidney and cardiac diseases.
• Patients, who are being treated permanently with anti-inflammatory or immunosuppressive drugs (e.g. corticosteroids or alpha / beta-a(nta)gonists, immuno suppressant drugs).
• Patients with severe psychiatric disorders (Axis I) such as schizophrenia, dementia, attention deficit hyperactivity disorder, obsessive-compulsive disorder, current alcohol, drugs or drug addiction.
• Patients who have already been treated unsuccessfully with sertraline and all alternate medications allowed in the study.
• Pregnant or lactating (breast feeding) women.