The Anxiety Sensitivity Index (ASI) is a 16-item self-report instrument that provides a measure of anxiety sensitivity (AS), a psychological construct that has been shown to be a central cognitive risk factor relevant to anxiety and its disorders.
Note: The ASI was only used in the Pilot questionnaire of assessment 1A, and was filled in by 2730 adult participants.
After the pilot, the ASI was dropped in favor of other personality tests: Neo-PI and PANAS.

AS is defined as the fear of arousal-related sensations (e.g., fear of heart palpitations), which arise from beliefs that these anxiety-related sensations have harmful consequences ¹⁾. Individual differences in AS are hypothesized to emerge from both genetic and maladaptive learning experiences that lead to the acquisition of beliefs about the aversive consequences of arousal and anxiety-related states ²⁾³⁾.

Taylor and colleagues developed the ASI-3 in order to assess the basic dimensions of anxiety sensitivity: (1) fear of physical symptoms, (2) fear of cognitive symptoms, and (3) fear of publicly observable symptoms ⁴⁾. Robust dimensions of anxiety sensitivity: Development and initial validation of the Anxiety Sensitivity Index-3. Psychological Assessment, 19, 176-188. DOI: 10.1037/1040-3590.19.2.176)). Each dimension predicts different types of psychopathology (e.g., fear of physical symptoms is most closely associated with panic disorder). The analysis of the dimensions of anxiety sensitivity provides are more nuanced way of examining the relationship between specific types of anxiety sensitivity and specific types of psychopathology.
Reiss (2013) has expanded the concept of a “motivational sensitivity” into a comprehensive theory of human motivation, known as the theory of 16 basic desires, or Reiss Motivation Profile. Everybody wants to be safe and avoid anxiety, for example, but people with high anxiety sensitivity place a significantly higher value on their safety than does the average person. Reiss's model is based on research on the largest cross-cultural database of human motives ever collected. It identifies 16 motivational sensitivities, one of which is called need for tranquillity, which is the same as anxiety sensitivity.

The validity and reliability of the 16-item ASI was tested in the general population ⁵⁾ and more recently in a population of Dutch young adults ⁶⁾.
There is a long list of papers describing the links between a high ASI-score and the development of disorders such as phobia and panic disorders, amongst others. A recent book by Steven Taylor ((Anxiety Sensitivity, 2014) gives a thorough overview.

Participants score 16 items on a 5-point Likert scale, ranging from “this does not apply to me at all” to “this does very much apply to me”.

Appendix 1. Overview of SUBSECTION_NAME variables.

Variable Question VMID Age Base question: Could you indicate to what extent the following statement applies to you (if you have never experienced the situation, try to answer the question imagining how you would feel if you would experience the situation). ASI1 Ik vind het belangrijk om niet zenuwachtig over te komen. 1 18-65 ASI2 When I cannot keep my mind on a task, I worry that I might be going crazy. Als ik ergens mijn aandacht niet bij kan houden, ben ik bang gek te worden. 1 18-65 ASI3 It scares me when I feel shaky (trembling). Het maakt me bang wanner ik me draaierig (trillerig) voel. 1 18-65 ASI4 It scares me when I feel faint. Het maakt me bang wanneer ik me duizelig voel. 1 18-65 ASI5 It is important to me to stay in control of my emotions. Ik vind het belangrijk om mijn emoties de baas te blijven 1 18-65 ASI6 It scares me when my heart beats rapidly. Het maakt mij bang wanneer mijn hart snel klopt. 1 18-65 ASI7 It embarrasses me when my stomach growls. Ik ben van slag wanneer mijn maag knort. 1 18-65 ASI8 It scares me when I am nauseous. Het maakt me bang wanneer ik me misselijk voel. 1 18-65 ASI9 When I notice that my heart is beating rapidly, I worry that I might have a heart attack. Wanneer ik merk dat mijn hart snel klopt, ben ik bang een hartaanval te krijgen. 1 18-65 ASI10 It scares me when I become short of breath. Het maakt me bang wanneer ik adem tekort kom. 1 18-65 ASI11 When my stomach is upset, I worry that I might be seriously ill. Wanneer mijn maag van streek is, ben ik bang erg ziek te worden. 1 18-65 ASI12 It scares me when I am unable to keep my mind on a task. Het maakt me bang wanneer ik ergens mijn aandacht niet bij kan houden. 1 18-65 ASI13 Other people notice when I feel shaky. Anderen merken aan mij dat ik me draaierig voel. 1 18-65 ASI14 Unusual body sensations scare me. Ongewone lichamelijke sensaties maken me bang. 1 18-65 ASI15 When I am nervous, I worry that I might be mentally ill. Wanneer ik me zenuwachtig voel, ben ik bang gek te worden. 1 18-65 ASI16 It scares me when I am nervous. Het maakt me bang wanneer ik me zenuwachtig voel. 1 18-65