Fear Conditioning Paradigm in Obesity (GenAllertOB)

Implicit Reactions to Threats in Individuals With Obesity: Primary Evidence From Fear Conditioning Paradigm

Fear processing in obesity and specifically the ability to i) learn and remember threatening stimuli, and ii) implicitly (i.e., unconsciously) and explicitly (consciously) discriminate them from neutral ones, will be investigated in affected individuals through the fear-conditioning paradigm.

Study Overview

• Status: Completed
• Conditions: Obesity
• Intervention / Treatment: Behavioral: Fear Conditioning

• Study Type: Observational
• Enrollment (Actual): 48

Contacts and Locations

Study Locations

• Italy
  • VCO
    • Piancavallo, VCO, Italy, 28824
      • IRCCS Istituto Auxologico Italiano - Ospedale San Giuseppe

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 50 years (Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Participants with obesity will be recruited at the beginning of a rehabilitative treatment at the Istituto Auxologico Italiano, IRCCS, San Giuseppe Hospital (Italy). Controls will be recruited out of the hospital.

Description

Inclusion criteria:

• Right-handed
• diagnosis of obesity (the level of body mass index - BMI - higher or equal to 30).

Exclusion criteria:

• concurrent neurological, neurodevelopmental (e.g., autism), motor, somatosensory and/or psychiatric disorders.

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Cases; Participants affected by obesity (the level of body mass index (BMI) higher or equal to 30).	Behavioral: Fear Conditioning; It is a 2-day paradigm. Participants will undergo an auditory fear conditioning task in 3 phases: (1) pre-conditioning habituation, (2) unconditioned stimulus (US) calibration, where USs will be delivered to set the individual stimulation intensity threshold, and (3) fear conditioning, in which participants will be exposed to the conditioned stimulus (CS) associated with the US with an 80% pairing rate. 24 hours later, the (1) implicit recognition of the CS and novel stimuli (NSs), and the (2) explicit recognition, through an alternative forced-choice task will be assessed. Also, (3) the perceptual discrimination (among the CS and NSs) will be tested. Event-related skin conductance responses (SCRs) will be collected as an implicit index of defensive fear responses, while the accuracy in detecting and discriminating the CS from NSs as the explicit index. Psychological questionnaires about anxiety symptoms will be also administered.
Controls; Not-hospitalized participants with a healthy weight	Behavioral: Fear Conditioning; It is a 2-day paradigm. Participants will undergo an auditory fear conditioning task in 3 phases: (1) pre-conditioning habituation, (2) unconditioned stimulus (US) calibration, where USs will be delivered to set the individual stimulation intensity threshold, and (3) fear conditioning, in which participants will be exposed to the conditioned stimulus (CS) associated with the US with an 80% pairing rate. 24 hours later, the (1) implicit recognition of the CS and novel stimuli (NSs), and the (2) explicit recognition, through an alternative forced-choice task will be assessed. Also, (3) the perceptual discrimination (among the CS and NSs) will be tested. Event-related skin conductance responses (SCRs) will be collected as an implicit index of defensive fear responses, while the accuracy in detecting and discriminating the CS from NSs as the explicit index. Psychological questionnaires about anxiety symptoms will be also administered.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
SCRs)	The event-related skin conductance responses (SCRs) in the case of the CS will be measured. This will represent the implicit index.	Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recognition %	Level of accuracy (in %) in recognizing and discriminating the CS from NS will be computed. This will represent the explicit index.	baseline

Collaborators and Investigators

• Sponsor: Istituto Auxologico Italiano

Study record dates

Study Major Dates

• Study Start (Actual): June 7, 2022
• Primary Completion (Actual): January 10, 2024
• Study Completion (Actual): January 10, 2024

Study Registration Dates

• First Submitted: February 22, 2023
• First Submitted That Met QC Criteria: March 3, 2023
• First Posted (Actual): March 14, 2023

Study Record Updates

• Last Update Posted (Estimated): August 27, 2025
• Last Update Submitted That Met QC Criteria: August 20, 2025
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: anxiety; fear conditioning; fear processing
• Additional Relevant MeSH Terms: Mental Disorders; Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity; Anxiety Disorders
• Other Study ID Numbers: 21X101

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No