Anxiety disorders are among the most common conditions affecting children and adolescents (Costello and Angold, 1995) with most modern epidemiological reports estimating the prevalence of significant anxiety disorders at greater than 10% worldwide (Pine, 1994) and from 12% to 20% in the USA (Kessler et al., 1994; Achenbach et al., 1995; Shaffer et al., 1996). Nevertheless, and in spite of the high prevalence, anxiety in childhood has not been as well studied as many other less common childhood disorders, possibly due to the incorrect perception that this problem is typically transient and innocuous (Benjamin et al., 1990). Over the last decade, however, our understanding of the phenomenology, prevalence, and treatment of childhood anxiety has increased dramatically. Although cognitive factors are presumed to play an important role in the expression and maintenance of childhood anxiety and most treatments contain at least some cognitive techniques specifically addressing these factors, only a handful of studies have been published investigating cognitive aspects of anxiety in children and adolescents.

In addition to the epidemiological findings, recent studies suggest that anxiety disorders in childhood are highly comorbid, relatively stable over time, and associated with significant impairment both acutely and over the long term. Clinic and community studies suggest that 50–75% of anxious children demonstrate two or more anxiety diagnoses (Costello and Angold, 1995; Last et al., 1987), and that comorbidity with both mood and externalizing disorders is also common (Bernstein and Borchardt, 1991; Ollendick and King, 1994).