Effectiveness of a Cognitive and Behavioral Treatment Program in People With Idiopathic Environmental Intolerance (IEI)

Last updated: August 7, 2025
Sponsor: Institut National de la Santé Et de la Recherche Médicale, France
Overall Status: Active - Recruiting

Phase

N/A

Condition

Hypochondriasis

Treatment

Cognitive Behavioral Therapy

Clinical Study ID

NCT05973214
C22-19
2022-A01370-43
  • Ages > 18
  • All Genders

Study Summary

Idiopathic Environmental Intolerance (IEI) denotes a functional disorder represented by heterogeneous symptoms that sufferers attribute to specific environmental agents and for which there may be no solid evidence of an underlying physiological cause.

We are conducting a randomized controlled trial study to compare patients before and after a newly developed cognitive behavioral therapy treatment program for IEI, with respect to behavioral and psychometric variables.

The results of this research project are expected to contribute to advancements in the clinical treatment of IEI, as well as to elaborate on existing theoretical models of IEI.

Eligibility Criteria

Inclusion

Inclusion Criteria:

  • Aged ≥18 years,

  • Present a diagnosis of idiopathic environmental intolerance confirmed by the leadphysician at the admission

  • Be affiliated to a social security regime.

  • Informed Consent

Exclusion

Exclusion Criteria:

  • Severe depression, delusion disorder or substance use disorder

  • No access to internet

  • Non-French speakers

  • Currently participating to another research on IEI

  • Under an exclusion period for another study

  • Benefiting from French state aid known as AME

  • Deprivation of liberty by court or administrative order

  • Hospitalized without consent

  • Under protective measures

  • Pregnancy and/or breastfeeding

Study Design

Total Participants: 82
Treatment Group(s): 1
Primary Treatment: Cognitive Behavioral Therapy
Phase:
Study Start date:
February 20, 2024
Estimated Completion Date:
November 30, 2028

Study Description

Introduction:

A percentage of the population report various, nonspecific somatic and cognitive symptoms (e.g., headaches, nausea, fatigue, difficulty concentrating...) that they causally attribute to agents in their environments (chemicals, electromagnetic fields, windmills..). This condition is called Idiopathic Environmental Intolerance (IEI). It is proposed that the attribution of symptoms to an environmental agent, and the associated negative expectations is what drives symptom experience. We hypothesize that this, alongside other cognitive biases, are involved in the emergence and maintenance of symptoms. Treatment models have been developed, but no cognitive behavioral therapy was tested on IEI patients.

The planned study aims to investigate the feasibility and efficacy of a cognitive behavioral treatment online program, in ameliorating quality of life in a French population of patients suffering from IEI.

Methods and analysis:

This parallel two-armed, randomized controlled trial, evaluates an 8-week guided intervention against a wait-list control group. It is a hybrid intervention that will include web-based consecutive modules based on disorder-specific cognitive behavioral therapy (CBT) as well as general transdiagnostic principles . Guidance will be provided by trained psychologists with weekly supportive feedback.

As part of the "BELIEF" project, the present study aims to recruit n=82 patients indicating symptom attributed to factors in the environment. Assessments will take place at baseline and after intervention completion (12 and 24 weeks after randomization). The primary outcome will be measured by the SF-12 scale for quality of life. Secondary outcomes include symptom perception, severity and distress, eco-anxiety, emotional processing, intolerance to uncertainty and associated mental disorders such as depression and anxiety. Consumption of healthcare services will also be measured.

Ethics and dissemination:

Ethics approval has been granted. Results from this study will be published in peer-reviewed journals and presented at international conferences.

Trial registration number: DRKS00014375

Connect with a study center

  • Unité de pathologies professionnelles et environnementales, Hôtel-Dieu

    Paris, 75004
    France

    Active - Recruiting

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