Interpersonal therapy of depression was created and established in American psychiatry in the 80ties. At that time european and especially german psychiatry was still dominated by the concept of endogenous depression, which suggested a somehow biologically determined aetiology which was not very likely to be influenced by psychotherapeutic access.

However, the empiric approach to evaluate therapy regardless of aetiology, which is very typical for IPT, produced strong evidence for the effectiveness of IPT in unipolar depression and many other psychiatric disorders.

On this basis, a diversity of biological studies became possible which aimed to the elucidation of neurobiological mechanisms of psychotherapy.

The first data indicate that biological state markers change when the patient responds, regardless if he received Psycho- or pharmacotherapy. However, no empirical findings suggested, how IPT might be linked to neurobiological phenomena.

We followed the suggestion by E. Kandel, that the phosphorylation of cAMP-responsive-binding-protein (pCREB) could be a crucial factor in the process of psychic improvement. Therefore we studied pCREB in human T-lymphocytes under different treatment conditions in unipolar depression. The results will be presented.