Psychophysiological and functional neuroimaging techniques in the study of anxiety disorders

Physiological responses are intimately associated with both normal and pathological anxiety states and are essential for the formal diagnosis of several anxiety disorders. However, clinical research and practice rely almost exclusively on self-report. Emotions manifest themselves in the cognitive, behavioural and physiological domains, even though these domains do not always (and should not necessarily) correlate. Psychophysiological variables can be useful in predicting the subsequent development of anxiety disorders and even clinical outcome with various treatments. They can also be used as measures of treatment change. Functional neuroimaging techniques permit very accurate localization of the brain regions involved in anxiety disorders, even in the absence of behavioural differences between patients and healthy controls. Finally, these techniques can potentially increase our understanding of the mechanisms of action of various treatments, which are yet to be fully understood, but this type of research is still in its infancy.