Protocol | Published:

Assessing fear and anxiety in humans using the threat of predictable and unpredictable aversive events (the NPU-threat test)

Nature Protocols volume 7, pages 527532 (2012) | Download Citation

Abstract

The threat of predictable and unpredictable aversive events was developed to assess short-duration (fear) and long-duration (anxiety) aversive states in humans. A typical experiment consists of three conditions: a safe condition (neutral (N)), during which participants are safe from aversive stimuli, and two threat conditions—one in which aversive events are administered predictably (P) (i.e., signaled by a threat cue), and one in which aversive stimuli are administered unpredictably (U). During the so-called NPU-threat test, ongoing change in aversive states is measured with the startle reflex. The NPU-threat test has been validated in pharmacological and clinical studies and can be implemented in children and adults. Similar procedures have been applied in animal models, making the NPU-threat test an ideal tool for translational research. The procedure is relatively short (35 min), simple to implement and generates consistent results with large effect sizes.

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Acknowledgements

This research was supported by the Intramural Research Program of the NIMH (MH002798 and MH002804-09).

Author information

Affiliations

  1. Genetic Epidemiology Research Branch, National Institute of Mental Health (NIMH), Bethesda, Maryland, USA.

    • Anja Schmitz
  2. Section on the Neurobiology of Fear and Anxiety, NIMH, Bethesda, Maryland, USA.

    • Christian Grillon

Authors

  1. Search for Anja Schmitz in:

  2. Search for Christian Grillon in:

Contributions

C.G. developed the NPU-threat test and edited the protocol. A.S. drafted the manuscript and contributed to paradigm modifications.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Anja Schmitz.

Supplementary information

PDF files

  1. 1.

    Supplementary Methods 1

    Questionnaire

  2. 2.

    Supplementary Table 1

    This table shows an example of the timing of all stimuli for a block. The table starts with 4 startle stimuli followed by the sequence PNUNUNP. Note that ITI stands for inter trial interval, which refers to the period without cue

  3. 3.

    Supplementary Methods 2

    Instructions

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DOI

https://doi.org/10.1038/nprot.2012.001

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