 The study hypothesis is that quetiapine XR has anxiolytic properties. The study aims to investigate the putative anxiolytic properties of quetiapine XR in patients with anxiety disorders. Therefore, in a proof-of-concept design patients with simple phobia will be selected to investigate specific anxiolytic and antipanic activity during acute anxiety. Moreover, in a combined fMRIvisual stimulus presentation paradigm activity of fear-network associated brain structures such as the amygdala will be investigated under treatment with quetiapine XR or placebo. Additionally, genetic factors potentially mediating anxiolytic properties of quetiapine will be studied. 