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charge. Some of these scales are available in languages other than English. Anxiety disorders F.1 9 IACAPAP Textbook of Child and Adolescent Mental Health Genetic factors There is little doubt that anxiety disorders are heritable. Best estimates suggest that around 40% of the variance in anxiety symptoms and in diagnoses of anxiety disorder is mediated by genetic factors. This estimate is even higher if one looks at stability of anxiety over time. Slightly less research – but with similar findings – has been done on anxiety specifically during the childhood years. Twin studies of anxiety in children indicate that around 30% to 40% of the variance in symptoms and disorders can be attributed to heritability (Gregory & Eley, 2007). There is some evidence (albeit with limitations) that heritability estimates for temperamental risk for anxiety (e.g., inhibition) is slightly higher (Rapee & Coplan, 2010). As mentioned above, genetic risk across anxiety disorders appears to be largely general and seems to primarily load on a very broad factor such as general neuroticism (Gregory & Eley, 2007). Work on specific genes underlying anxiety disorders is less extensive and, to date, no evidence exists linking any individual gene specifically to anxiety. Many candidates have been explored; the most widely studied being the promoter region of the serotonin transporter gene (5HTTLPR). However, polymorphisms on this gene have been associated with different disorders and it is unlikely that it would play a specific role in anxiety. In fact, one theory states that having two short alleles on the 5HTT gene may generally increase an individual’s overall responsiveness to environmental events (both positive and negative) (Belsky et al, 2009). Temperamental factors Temperamental risk for anxiety is probably the best studied and most clearly established risk factor (Fox et al, 2005; Rapee et al, 2009). A variety of similar temperaments have been associated with child anxiety including: behavioural inhibition, withdrawal, shyness, and fearfulness. I will refer to these various temperaments in this section under the general term inhibition. Extensive research has shown that very young children who are identified as high on inhibition are at greater risk for later anxiety disorders. As described above, research has also linked inhibition with anxiety disorders in first degree relatives. The most common assessment of inhibition occurs in children from around two to five years of age. This may be done via questionnaires or direct observation. Common features of inhibition include: • Withdrawal in the face of novelty • Slowness to warm up to strangers or peers • Lack of smiling • Close proximity to an attachment figure • Lack of talk • Limited eye contact or “coy” eye gaze • Unwillingness to explore new situations. Children who show these characteristics during preschool age are two to four times more likely to meet criteria for anxiety disorders by middle childhood and this increased risk has been shown to continue at least into adolescence (Fox et al, 2005). Some evidence has also indicated that infants (aged 3-6 months) who show high levels of arousal and emotionality are at greater risk to show high inhibition by two to five years. Therefore, it seems to be possible to identify increased risk for anxiety from a few months of age (Kagan & Snidman, 1991). Theoretically, the main complication with this research is the extensive overlap between the constructs of inhibition and anxiety disorders. Thus, one could argue that inhibition is simply a less clear version or an early manifestation of an anxiety disorder. There is some evidence that inhibition and disorder have Jerome Kagan, professor of psychology at Harvard University, is one of the scholars who contributed to developing the concept of temperament, which he defined as stable behavioural and emotional reactions that appear early in life. He described two types of temperament: inhibited and uninhibited. The former applies to children who are shy, timid, socially withdrawn and fearful, while the latter refers to children who are outgoing, sociable and daring. Anxiety disorders F.1 10 IACAPAP Textbook of Child and Adolescent Mental Health some unique features and thereby represent distinct constructs but the issue is far from settled (Rapee & Coplan, 2010). Parent and family factors Given the evidence for the transmission of anxiety within families described above, it has commonly been assumed that parents and the family environment must contribute to the development of anxiety disorders. However, evidence has been difficult to obtain and data have not been entirely consistent. The most extensive research has focussed on parenting and parent-child interactions. There is now little doubt that the parenting of anxious children is characterised by overprotection, intrusiveness and, to a lesser extent, negativity (McLeod et al, 2007). Whether this relationship is causal is much harder to determine and, to date, there has been very little examination of this issue. Theories argue that the parent-child relationship is likely to reflect cyclical interactions. That is, inhibited children are likely to elicit overprotection from their parents and, in turn, overprotective parenting is likely to lead to further anxiety (Hudson & Rapee, 2004; Rubin et al, 2009). Few longitudinal studies have addressed this relationship, but at least some
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