The Parasite and Infestation Study

NCT07849907 | Recruiting

• 1 other identifier: 201489
• Study Type: observational
• Target: 25
• Locations: 1 country
• Sites: 1

Brief Summary

Many people have evidence of bugs, parasites, and infestation, but are told by others that they cannot find a cause. This distressing and frustrating experience can last for years, as the person seeks answers. The current study aims to understand the experience of these individuals. In a 1-2 hour session over Zoom, the investigators will ask participants questions about their experience, have them complete self-report questionnaires, and ask them to complete a few games on the computer. The investigators' goal is to help characterize and understand individuals with this experience to aid in better treatment and inform recommendations for providers.

Conditions

Parasite and Infestation Physician-Patient Diagnostic Incongruency

Keywords

parasites; infestation; Morgellons Disease; bugs crawling; tactile

Outcome Measures

Primary Outcomes (10)

• Psychological Wellbeing

  Total score on the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS); scores range from 14-70; higher scores reflect greater wellbeing

  Baseline

• Social Network

  Ludden Social Network Scale - total score; higher scores reflect larger and closer social network (score: 0-30)

  Baseline

• Depression

  Total score - Beck Depression Inventory -II; Scores range from 0-63 with higher scores reflecting worse depression

  Baseline

• Anxiety

  Perseverative Thinking Questionnaire (PTQ); scores range from 0-60, higher scores reflect more perseveration

  Baseline

• Belief Updating

  Expectations of prior volatility (mu3) calculated from reversal learning task; higher parameter scores reflect greater expectations of volatility

  Baseline

• BADE

  Evidence Integration Impairment (EII) will be calculated based on decisions on the Bias Against Disconfirmatory Evidence task. Higher scores reflect more difficulty integrating information

  Baseline

• Interoceptive Awareness

  Multidimensional Assessment of Interoceptive Awareness-2; scores range from 0-185; higher scores reflect better interpersonal awareness

  Baseline

• Dissociation

  Cernis Felt Sense of Anomaly Scale (CEFSA); scores range from 0-140, higher scores reflect more severe dissociative experiences

  Baseline

• Childhood Trauma

  Childhood Trauma Questionnaire (CTQ)- scores range from 5-100, higher scores reflect more severe childhood maltreatment

  Baseline

• DACOBS

  Davos Assessment of Cognitive Biases Scale; higher scores reflect more severe cognitive biases. Scores range from 42-294

  Baseline

Study Arms (1)

PPDI Group

Other: No intervention - observational study

Interventions

No intervention - observational study OTHER

This study will not involve an intervention.

PPDI Group

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adults with a persistent experience of infestation or parasite that physicians or other professionals report no evidence for.

You may qualify if:

• Men and women aged 18-70 years old
• At least 50% certain that they have an active infection/infestation/parasite, despite being told by doctor that they do not
• Ability to read and speak English
• Access to a computer or phone for virtual visit
• No self-reported history of schizophrenia-spectrum disorder

You may not qualify if:

• Active substance use disorder (excluding nicotine and caffeine)
• History of severe head trauma
• Current use of antipsychotics
• Serious medical or neurological illness known to interfere with cognitive functioning
• Diagnosis of a learning disability or cognitive disorder

Sponsors & Collaborators

• Vanderbilt University Medical Center: lead

Study Sites (1)

Vanderbilt University Medical Center

Nashville, Tennessee, 37212, United States

RECRUITING

MeSH Terms

Conditions

Parasitic Diseases; Morgellons Disease

Condition Hierarchy (Ancestors)

Infections; Skin Diseases; Skin and Connective Tissue Diseases; Schizophrenia Spectrum and Other Psychotic Disorders; Mental Disorders

Study Officials

• Julia Sheffield, PhD

  Vanderbilt University Medical Center

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Sheffield Lab

CONTACT

(615) 686-2488; sheffieldlab.vumc@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Study Record Dates

• First Submitted: September 18, 2026
• First Posted: September 30, 2026
• Study Start: December 31, 2024
• Primary Completion (Estimated): December 1, 2029
• Study Completion (Estimated): December 1, 2030
• Last Updated: September 30, 2026

Record last verified: 2026-09

Locations

US (1)