Health Anxiety Inventory-18

What it measures?

• The items of the HAI-18 are intended to evaluate health anxiety regardless of physical health status. These items measure concerns about health, awareness of bodily sensations or changes, and the feared consequences of having an illness.
• The HAI-18 (also known as the SHAI) is an 18-item abbreviated version of the original 64-item Health Anxiety Inventory (HAI; Salkovskis et al. 2002).
• To develop the SHAI, Salkovskis et al. selected the 14 items from the HAI that had the highest item-total correlation in a sample of health care patients. They then added four additional items based on theoretical considerations. A two-factor solution best represents the SHAI items in both nonclinical and clinical samples (Abramowitz et al. 2007b; Wheaton et al. 2010).
• Many earlier studies, including a systematic review have supported a two-factor structure, consisting of Illness Likelihood (items 1-14; i.e: fear of developing a serious health condition or illness) and Negative Consequences (sometimes referred to as Illness Severity; items 1-15; i.e. affective concerns about the negative ramifications of acquiring an illness or health condition; Alberts et al., 2010; Fergus & Valentiner, 2011; Wheaton et al., 2010). More recent research has found only weak support for the proposed subscales, arguing that HAI-18 items tap a single underlying construct (Axelsson et al., 2023). These authors found that “worry about health and the fear of serious illness was at the core of the trait health anxiety constructel” (Axelsson et al., 2010, p. 11).

Who is it for?

Adults aged 18 years +

Instrument Quality

• The shorter version of the health anxiety measure has been widely used in various settings and has demonstrated comparable performance to other well-established health anxiety assessment tools (Axelsson et al., 2023).

Structure

• 18 items
• 4-point Likert scale
• For each item, respondents must choose from several statements assessing the extent of health- and somatic-related concerns during the past 6 months (e.g. “I occasionally worry about my health”).
• Each item is scored from 0 to 3 points, with less healthy responses yielding a higher item score.

Scoring instructions

• Sum all item responses to derive the full-scale HAI-18 score.

Score Interpretation

What higher scores mean?

• Higher scores on the HAI-18 indicate more severe health anxiety. Research by Axelsson and colleagues (2023) supports the following severity ranges: Normative range (0-25): Indicates non-clinical levels of health anxiety according to other established health anxiety measures. In a sample of healthy volunteers (N = 88) the mean HAI-18 score was 8.1 (SD = 4.5). Mild pathological health anxiety (26-32): Indicates pathological health anxiety at a mild level, which may require some clinical attention. For comparison with other established measures of health anxiety, a cutoff of 26 roughly corresponds to a score of 22 on the HAI-14, 82–83 on the HAI-64, 52–53 on the IAS, and 7–8 on the WI-14. Moderate pathological health anxiety (33-39): Indicates symptoms of health anxiety that are not quite within severe and clinical range—but not mild either. The ‘moderate’ label is not explicitly referenced by Axelsson and colleagues (2023), but is inferred through their comparison of HAI-18 severity ranges with those of other health anxiety assessment instruments. In patients diagnosed with Somatic Symptom Disorder or Illness Anxiety Disorder (N = 335), based on the DSM-5 criteria, the average HAI-19 score was 35.5 (SD = 6.2; Axelsson et al., 2023). Clinical (severe) pathological health anxiety (40-53): Indicates ‘substantial’ health anxiety symptoms that are likely to be within a clinical range. The patient is likely to be experiencing significant distress. Maximum (54): A score of 54 on the HAI-18 is the highest possible score, reflecting severe health anxiety.

Instrument developers

• Salkovskis, P. M., Rimes, K. A., Warwick, H. M. C., & Clark, D. M. (2002). The Health Anxiety Inventory: Development and validation of scales for the measurement of health anxiety and hypochondriasis. Psychological Medicine, 32(5), 843 853. https://doi.org/10.1017/S0033291702005822.

Refrences

* Axelsson, E., Österman, S., & Hedman-Lagerlöf, E. (2023). Joint factor analysis and approximate equipercentile linking of common trait health anxiety measures: a cross-sectional study of the 14-, 18-and 64-item health anxiety inventory, the illness attitude scale, and the 14-item Whiteley Index. BMC psychiatry, 23(1), 658. * Fergus, T. A., & Valentiner, D. P. (2011). The short health anxiety inventory and multidimensional inventory of hypochondriacal traits: A comparison of two self-report measures of health anxiety. Cognitive Therapy and research, 35, 566-574. * Salkovskis, P. M., Rimes, K. A., Warwick, H. M. C., & Clark, D. M. (2002). The Health Anxiety Inventory: Development and validation of scales for the measurement of health anxiety and hypochondriasis. Psychological Medicine, 32(5), 843–853. https://doi.org/10.1017/S0033291702005822. * Warwick, H. M. & Salkovskis, P. M. (1990). Hypochondriasis. Behaviour Research and Therapy 28, 105–117. * Warwick, H. M., Clark, D. M., Cobb, A. M., & Salkovskis, P. M. (1996). A controlled trial of cognitive–behavioural treatment of hypochondriasis. The British Journal of Psychiatry, 169(2), 189-195. * Wheaton, M. G., Berman, N. C., Franklin, J. C., & Abramowitz, J. S. (2010). Health anxiety: Latent structure and associations with anxiety-related psychological processes in a student sample. Journal of Psychopathology and Behavioral Assessment, 32, 565-574.