Aetiology and mechanisms of anxiety disorders.

Theories on the aetiology of pathological anxiety abound. A critical review is given of the most influential approaches (e.g. psychoanalytical, "somatogenic", behavioural, psychophysiological and "biological" theories), with emphasis on panic and agoraphobic disorders. Evidence is presented from epidemiological and genetic research and from observations on the course of illness. A surprisingly constant prevalence of anxiety syndromes, and a familial distribution suggesting a pivotal importance of genetic factors, speak in favour of a biological model. The course of illness, however, points to the importance of environmental influences as triggering factors, and to cognitive and behavioural mechanisms for the perpetuation of the symptoms. Treatment responses hitherto documented support the biological and behavioural concepts, but the cognitive and psychophysiological theories are also supported to some extent. An attempt is made to combine these findings with biochemical and pharmacological findings in an integrated model of panic and agoraphobia. This model takes the form of a vicious circle, and is compatible with biological and neuropharmacological as well as evolutionary and psychological concepts.