Asthma nervosa: old concept, new insights.

S tress has long been recognised to be associated with asthma. Hippocrates stated that to prevent an asthma attack ''the asthmatic should guard himself against his own anger'' [1]. Maimonides in his treatise of asthma suggested that ''mental anguish, fear, mourning or distress'' may cause asthma whereas ''gaiety and joy'' which ''gladden the heart and stimulate the blood and mental activity'' may have the opposite effect [2]. In his treatise, H.H. Salter wrote that ''asthma is essentially, and with perhaps the exception of a single class of cases, exclusively a nervous disease; the nervous system is the seat of the essential pathological condition'' [3], and W. Osler referred to asthma as ''a neurotic affection'' [4]. Thus, until the second half of the 20th century, asthma was predominantly viewed as a psychosomatic disorder in which emotional stress and imbalances in the nervous system were key factors in its aetiology. As a result, relief of anxiety was considered the main therapeutic intervention for ''asthma nervosa''; as it has been referred to historically. Although the increased awareness in the second half of the 20th century of other triggers of asthma (allergens and air pollution) has shifted the focus away from psychosocial factors, these old concepts are going through a renaissance, with an increasing number of publications reporting consistent positive associations between psychosocial stress and asthma. Associations with asthma have been shown for a wide range of stressors including: post-traumatic stress disorder (PTSD) [5, 6]; psychiatric disorders [7, 8]; community violence [9]; stressful life events [10]; partner violence and housing quality [11]; war-related stress [12]; neuroticism and relational problems [13]; perceived safety [14]; social depravity and high crime rates [15]; anxiety and attention disorders [16]; psychological distress [17]; maternal anxiety [18]; maternal depression and paternal PTSD [19]; and work-related stress [20]. Conversely, the prevalence of asthma has been shown to be elevated in those suffering from anxiety disorders [21]. The cross sectional nature of most of these studies has prevented firm conclusions from being drawn regarding causality and direction of the relationship. However, there is now a growing body of evidence within the last decade (table 1), and even prior to this [27], suggesting that emotional stress, anxiety and PTSD precedes the development of asthma both in children and adults. Similarly, there is evidence that asthma precedes panic disorders and that panic disorders may exacerbate pre-existing asthma [21]. These associations remain even after adjusting …