Anxiety Disorders (ADs) are the most prevalent mental disorders worldwide and are characterized by a wide variety of psychological and somatic symptoms, which are often misinterpreted as symptoms of a medical condition. ADs carry a large disease burden that impacts negatively on patients’ health-related quality of life and global life satisfaction and disrupts important activities of daily living. In this chapter we analyze the epidemiology and clinical presentation of ADs, highlighting recent innovations and changes in the classification of anxiety disorders in DSM-5 and ICD-11. Main available pharmacological and nonpharmacological therapies for the treatment of ADs, based on the most recent clinical evidence and updated literature, are presented as well. Lastly, we focus the attention on future perspectives about ADs, examining clinical correlations of peripheral biomarkers, neuroimaging, genetics, epigenetics, and microbiota data. These features may be useful to achieve further insight in terms of physiopathology, to support early diagnosis, and to facilitate the prediction of illness susceptibility and treatment response, in order to support clinicians’ practice and to develop personalized treatment strategies.