The word anxiety comes from the latin word anxieta which means troubled in the mind about some uncertain event, and has a Greek root anxo which means to squeeze, strangle or press tight. Anxiety disorders are a group of disorders with symptomatology that are different from each other, yet show the same basic emotion of anxiety as its predominant symptom.
Patients with such disorders often cope by avoidance behaviour. Anxiety disorders are common and these include generalised anxiety disorder, panic disorder, phobic disorder, obsessive compulsive disorder and post-traumatic stress disorder.
In a community survey of 3,020 persons aged 13 to 65 years in Singapore, the 12-month prevalence for any anxiety disorder was 9.3 % (CSL Fones, EH Kua, TP Ng, SM Ko Singapore Medical Journal 1998; 39(6): 251-255). As the latter two have distinct characteristics, they will be discussed in separate chapters (Chapters 12 and 13).