Parasite and Infestation Physician-Patient Diagnostic IncongruencyNCT07849907
The Parasite and Infestation Study
An observational study of Parasite and Infestation Physician-Patient Diagnostic Incongruency, run by Vanderbilt University Medical Center at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Parasite and Infestation Physician-Patient Diagnostic Incongruency
- How many people
- 25 participants
- Where
- 1 siteUnited States
- Study dates
- 31 Dec 2024to Dec 2030
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Adults with a persistent experience of infestation or parasite that physicians or other professionals report no evidence for.
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Vanderbilt University Medical Center
Nashville, Tennessee, 37212
Sheffield Lab, (615) 686-2488, sheffieldlab.vumc@gmail.com
About this study
Official title: Understanding the Experience of Patient-Physician Diagnostic Incongruency: I Know Something is Wrong But No One Believes Me
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.
Read the detailed description
The current study aims to characterize the experiences of people who have evidence of bugs, parasites, and/or infestation but are told by physicians or other professionals (e.g. vets, pest control) that there is nothing wrong. The investigators seek to understand the emotional and cognitive aspects of this experience, through semi-structured interviews, self-report questionnaires, and cognitive tasks. The study will take a few hours and is conducted remotely, allowing for participation regardless of the participant's physical location. There is practically no aggregate information on this experience, with most current information relying on case reports and medical record review. The investigators hope to provide greater insights into this experience to guide support for individuals going through this difficult process.
- Being tested
- No intervention - observational study
- Keywords
- parasites, infestation, Morgellons Disease, bugs crawling, tactile
- Medical subject headings
- Parasitic Diseases, Morgellons Disease
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
No intervention - observational studyOther
This study will not involve an intervention.
| Study group | Role | What they receive |
|---|---|---|
| PPDI Group | Not described Receives: Other: No intervention - observational study |
What is being measured
The primary outcome is the main question the study is designed to answer.
Psychological Wellbeing
Total score on the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS); scores range from 14-70; higher scores reflect greater wellbeing
Measured: Baseline
Social Network
Ludden Social Network Scale - total score; higher scores reflect larger and closer social network (score: 0-30)
Measured: Baseline
Depression
Total score - Beck Depression Inventory -II; Scores range from 0-63 with higher scores reflecting worse depression
Measured: Baseline
Anxiety
Perseverative Thinking Questionnaire (PTQ); scores range from 0-60, higher scores reflect more perseveration
Measured: Baseline
Belief Updating
Expectations of prior volatility (mu3) calculated from reversal learning task; higher parameter scores reflect greater expectations of volatility
Measured: 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
Measured: Baseline
Interoceptive Awareness
Multidimensional Assessment of Interoceptive Awareness-2; scores range from 0-185; higher scores reflect better interpersonal awareness
Measured: Baseline
Dissociation
Cernis Felt Sense of Anomaly Scale (CEFSA); scores range from 0-140, higher scores reflect more severe dissociative experiences
Measured: Baseline
Childhood Trauma
Childhood Trauma Questionnaire (CTQ)- scores range from 5-100, higher scores reflect more severe childhood maltreatment
Measured: Baseline
DACOBS
Davos Assessment of Cognitive Biases Scale; higher scores reflect more severe cognitive biases. Scores range from 42-294
Measured: Baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Sep 2026
- Study start31 Dec 2024
- Primary completionDec 2029 (estimated)
- Study completionDec 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Parasite and Infestation Physician-Patient Diagnostic IncongruencyStudies of the same condition, open and under way.
- More trials run by Vanderbilt University Medical CenterThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 25 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Vanderbilt University Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Julia Sheffield, Vanderbilt University Medical Center
- Investigators
- Julia Sheffield, PhD, Principal investigator, Vanderbilt University Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07849907
- Sponsor's protocol ID
- 201489
- Status last verified
- Sep 2026
- First submitted
- 18 Sep 2026
- Last updated
- 30 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 30 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Understanding the Experience of Patient-Physician Diagnostic Incongruency: I Know Something is Wrong But No One Believes Me
- ClinicalTrials.gov ID
- NCT07849907
- Acronym / sponsor ID
- 201489
- Keywords
- parasites, infestation, Morgellons Disease, bugs crawling, tactile
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 25 participants (estimated)
- Lead sponsor
- Vanderbilt University Medical CenterUniversity, hospital or other
- Study start
- 31 Dec 2024 (actual)
- Primary completion
- Dec 2029 (estimated)
- Study completion
- Dec 2030 (estimated)
- First posted
- 30 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
The current study aims to characterize the experiences of people who have evidence of bugs, parasites, and/or infestation but are told by physicians or other professionals (e.g. vets, pest control) that there is nothing wrong. The investigators seek to understand the emotional and cognitive aspects of this experience, through semi-structured interviews, self-report questionnaires, and cognitive tasks. The study will take a few hours and is conducted remotely, allowing for participation regardless of the participant's physical location. There is practically no aggregate information on this experience, with most current information relying on case reports and medical record review. The investigators hope to provide greater insights into this experience to guide support for individuals going through this difficult process.
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| PPDI Group | – | Other: No intervention - observational study |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Adults with a persistent experience of infestation or parasite that physicians or other professionals report no evidence for.
Key inclusion criteria (5 listed)
- 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
Key exclusion criteria (5 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| No intervention - observational studyThis study will not involve an intervention. | Other | PPDI Group |
Primary outcome
Psychological Wellbeing
Time frame: Baseline
Total score on the Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS); scores range from 14-70; higher scores reflect greater wellbeing
Social Network
Time frame: Baseline
Ludden Social Network Scale - total score; higher scores reflect larger and closer social network (score: 0-30)
Depression
Time frame: Baseline
Total score - Beck Depression Inventory -II; Scores range from 0-63 with higher scores reflecting worse depression
Anxiety
Time frame: Baseline
Perseverative Thinking Questionnaire (PTQ); scores range from 0-60, higher scores reflect more perseveration
Belief Updating
Time frame: Baseline
Expectations of prior volatility (mu3) calculated from reversal learning task; higher parameter scores reflect greater expectations of volatility
BADE
Time frame: Baseline
Evidence Integration Impairment (EII) will be calculated based on decisions on the Bias Against Disconfirmatory Evidence task. Higher scores reflect more difficulty integrating information
Interoceptive Awareness
Time frame: Baseline
Multidimensional Assessment of Interoceptive Awareness-2; scores range from 0-185; higher scores reflect better interpersonal awareness
Dissociation
Time frame: Baseline
Cernis Felt Sense of Anomaly Scale (CEFSA); scores range from 0-140, higher scores reflect more severe dissociative experiences
Childhood Trauma
Time frame: Baseline
Childhood Trauma Questionnaire (CTQ)- scores range from 5-100, higher scores reflect more severe childhood maltreatment
DACOBS
Time frame: Baseline
Davos Assessment of Cognitive Biases Scale; higher scores reflect more severe cognitive biases. Scores range from 42-294
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Sep 2026.
- Individual participant dataSharing planned: Undecided
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Julia Sheffield, PhD principal investigator
Vanderbilt University Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Parasite and Infestation Physician-Patient Diagnostic Incongruency, run by Vanderbilt University Medical Center at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 30 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sheffield Lab ((615) 686-2488, sheffieldlab.vumc@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Psychological Wellbeing (time frame: Baseline). The study lists 10 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Sep 2026.