My research is concerned with the understanding of neurobiological and psychological processes of fear and anxiety with the main focus on the mechanisms of change in the treatment of anxiety and related disorders. Although cognitive behavioural therapy (CBT) is effective in reducing fear for most anxiety disorders, a high percentage of patients experience a relapse even after apparently successful treatment. The prevailing view on the return of fear is that CBT can eliminate all fearful responding , but does not erase the original fear memory. Partial or full reappearance of fear may be explained by intact fear memories that resurface. Once a fear memory has been established, it is held to be forever. Insights from neuroscience suggest that it is unnecessarily defeatist to regard fear memory as irreversible. Fear conditioning research in animals and humans shows that reactivation of a consolidated fear memory can turn it to a labile, sensitive state in which the memory trace can be changed. Disruption of fear memory reconsolidation may prevent the return of fear and is thereby a promising therapeutic strategy for patients with anxiety and related disorders. We utilise the fear-conditioning paradigm to achieve a better understanding of the optimal and boundary conditions of changing fear memory. I believe that basic research is required for a step-change improvement of treatment for psychiatric disorders.