The present invention relates to the use of bombesin / gastrin releasing peptide antagonist in the preparation of pharmaceutical composition, said pharmaceutical composition is used for treating inflammatory diseases and immune-mediated inflammatory diseases, especially sepsis , acute lung injury and rheumatoid arthritis and for the treatment or prevention of brain disorders, preferably bipolar disorders, and in particular of different types and / or subtypes of bipolar disorders such as mania, acute mania, Severe mania, hypomania, depression, moderate depression, dysthymia, major depressive disorder, manic and / or depressive episodes, psychotic / psychotic symptoms (e.g., hallucinations, delusions), mixed bipolar states, Bipolar I disorder, bipolar II disorder, and / or rapid cycling bipolar disorder. In particular, specific nonapeptides with antagonist properties against bombesin or bombesin-like peptides such as gastrin-releasing peptide can be used in the treatment of inflammatory and immune-mediated inflammatory diseases and brain disorders .