Intolerance of Uncertainty Scale - Short Form (IUS-12)
What it is
The IUS-12 is a 12-item self-report measure of intolerance of uncertainty — the dispositional tendency to find ambiguous or uncertain situations distressing and difficult to tolerate. It is a shortened version of the original 27-item Intolerance of Uncertainty Scale (IUS), developed by Carleton, Norton, and Asmundson (2007) through factor analysis to retain the most psychometrically robust items.
Intolerance of uncertainty is recognised as a transdiagnostic process that contributes to a range of conditions, including generalised anxiety disorder, social anxiety, obsessive-compulsive disorder, depression, and eating disorders. The IUS-12 is widely used in research and clinical settings to assess this construct quickly and reliably.
How is it used
- Suitable for adults aged 18 and over
- Takes approximately 2–4 minutes to complete
- Can be used at baseline and follow-up to monitor change in response to therapy, particularly cognitive-behavioural interventions targeting worry and uncertainty
- Useful as a transdiagnostic indicator across anxiety, mood, and obsessive-compulsive presentations
The IUS-12 captures two related but distinct dimensions of intolerance of uncertainty:
- Prospective Anxiety: the tendency to find future uncertainty distressing and to seek predictability
- Inhibitory Anxiety: the extent to which uncertainty interferes with action and day-to-day functioning
What do the scores mean?
Each item is rated on a five-point scale from 1 (not at all characteristic of me) to 5 (entirely characteristic of me). The total score is the sum of all 12 items, ranging from 12 to 60. Higher scores indicate greater intolerance of uncertainty.
As a general guide for the total score:
- 12–21: Low intolerance of uncertainty
- 22–32: Moderate intolerance of uncertainty
- 33–60: High intolerance of uncertainty
Two subscales can also be calculated:
- Prospective Anxiety (items 1, 2, 4, 5, 8, 11): score range 6–30
- Inhibitory Anxiety (items 3, 6, 7, 9, 10, 12): score range 6–30
The IUS-12 is best interpreted alongside other clinical information. Higher scores are consistently associated with greater symptoms of worry, anxiety, depression, and obsessive-compulsive features, and reductions in scores are often seen following targeted CBT interventions.
Developer
The original 27-item IUS was developed in French by Freeston and colleagues (1994) and translated into English by Buhr and Dugas (2002). The 12-item short form was developed and validated by Carleton, Norton, and Asmundson (2007).
References:
Carleton, R. N., Norton, M. A. P. J., & Asmundson, G. J. G. (2007). Fearing the unknown: A short version of the Intolerance of Uncertainty Scale. Journal of Anxiety Disorders, 21(1), 105–117.
Freeston, M. H., Rhéaume, J., Letarte, H., Dugas, M. J., & Ladouceur, R. (1994). Why do people worry? Personality and Individual Differences, 17(6), 791–802.
Buhr, K., & Dugas, M. J. (2002). The Intolerance of Uncertainty Scale: Psychometric properties of the English version. Behaviour Research and Therapy, 40(8), 931–945.