Can Morgellons Be Diagnosed as a Delusion? What a New Psychodermatology Review Gets Right—and Wrong

Research criticism • Psychodermatology • Source audit

A 2026 review correctly challenges reflexive psychiatric dismissal. Its own infectious claims, however, do not survive the same citation-level scrutiny.

A patient can have real skin lesions, real fibers, real crawling sensations—and still face an unresolved question about what caused them. That is why disease versus delusion is the wrong binary.

The new review “Morgellons Disease and Psychodermatology”, by Marianne Middelveen, Melissa Fesler, and Raphael Stricker, is strongest when it separates observation from psychiatric interpretation. It is weakest when it stops applying that separation to its own preferred explanation.

That matters beyond an academic dispute. Real patients are sorted by these claims: toward investigation or dismissal, toward antibiotics or antipsychotics, and sometimes toward years of treatment. A citation that reverses a trial result is not a cosmetic error when clinical credibility is at stake.

The review deserves a close reading rather than a verdict by affiliation. Applied symmetrically, that reading produces two conclusions at once: clinicians should not diagnose delusion merely because a patient reports fibers, and advocates should not diagnose infection merely because a favored laboratory reports it.

Four Questions That Must Stay Separate

Morgellons arguments often collapse four different questions:

Evidence for one layer does not settle the others. A sensation is not automatically a delusion. A visible filament does not establish its origin. A positive infection test does not show that the infection produced the filament or the belief. And an incorrect causal theory is not, by itself, proof of a delusional disorder.

An observation is not an etiology. A test result is not an attribution.

The four questions are not a compromise between camps. They are a way to prevent either camp from answering the question it prefers instead of the one the evidence can actually resolve. A 2018 psychiatric review by Lai and colleagues similarly argued that a reported fiber can be real even when its interpretation remains mistaken, overvalued, or delusional.

The DSM Requires Attribution, Not Mere Coexistence

Question 3 versus Question 4: Does a medical condition cause the disturbance, or merely coexist with it?

This is the review’s central diagnostic error. DSM-5-TR excludes delusional disorder when the disturbance is “attributable to” a substance or another medical condition. The review reproduces that language, then effectively substitutes a lower threshold: if sensitive testing identifies Lyme disease, relapsing-fever borreliosis, or another infection, a delusional-disorder diagnosis becomes inappropriate.

But attributable to does not mean found in the same patient.

Suppose a patient has laboratory evidence of infection and also believes that government nanotechnology is emerging from the skin. The infection may be relevant to the patient’s health, but its presence alone does not establish that it caused that belief. Conversely, a clinician cannot call the belief primary delusional disorder without adequately investigating plausible medical causes. The attribution step is required in both directions.

The review is therefore right to insist on medical assessment. It is not justified in treating detection as causation. That substitution turns a diagnostic safeguard into an etiologic shortcut.

What the Review Gets Right

Questions 1, 2, and 4: Symptoms, findings, and beliefs require different evidence.

Several distinctions in the review are important and clinically humane:

• Formication is a sensation, not a diagnosis. It becomes evidence of delusion only when joined to a fixed false explanation and the rest of the diagnostic picture.
• Bringing fibers, photographs, or other specimens to an appointment is not a DSM criterion and is not pathognomonic of mental illness.
• An embedded or projecting filament is an observable finding. Denying the finding without examination is not psychiatric expertise.
• Morgellons patients are heterogeneous. Some may hold bizarre or fixed beliefs; others may describe only visible skin findings and physical symptoms.

These points protect patients from a familiar failure: the clinician recognizes the kind of story, assumes the ending, and stops looking. Our earlier review of the fiber literature reached a related conclusion. The fiber question needs controlled collection, microscopy, chemical characterization, and comparison—not reflexive acceptance or reflexive dismissal.

The review’s correction is necessary. It is simply not sufficient to establish the infectious model the authors favor.

Three Claims, Checked Against the Record

Issue	What the review does	What the record shows
Pearson 2012	Does not discuss or cite the CDC/Kaiser investigation.	The first and largest population-based Morgellons investigation found no common infection, while explicitly declining to decide whether the presentation was a new condition or wider recognition of delusional infestation.
Pimozide	Says the only randomized trial improved itch but not infestation beliefs or excoriation, citing Hamann and Generali.	Hamann reports significant relief of both itch and delusions; Generali says the case literature shows efficacy in a majority. Neither source supports the review’s negative characterization.
Universal infection detection	Says one or more tick-borne infections will “reliably be detected” with sensitive testing.	Every citation attached to that sentence is prior work by Middelveen, Fesler, Stricker, or Savely. The claim has no independent evidentiary base in the review.

Each problem concerns a different layer of the four-question frame. Together, they show why source fidelity matters as much as bedside openness.

The Missing Study Matters

Question 2 versus Question 3: What material was found, and what does it imply about cause?

The review’s 47-entry reference list contains no Pearson entry, and the 2012 CDC/Kaiser study appears nowhere in the body.

Study flow shown as labeled stages, not to scale. The clinical sample was much smaller than the source population.

Pearson and colleagues searched a Kaiser Permanente population of about 3.2 million enrollees, identified 115 case-patients under a broad self-report definition, and clinically evaluated 41. Most collected materials were cellulose, probably cotton, and the investigators found no common infectious source. Those findings weigh against a single established infectious explanation for the population they studied.

They do not prove that every person using the Morgellons label is delusional. The case definition was broader than a tissue-verified filament criterion, participation narrowed the clinically examined group, and the authors expressly said they could not determine whether the presentation was a new condition or wider recognition of an existing one such as delusional infestation.

The new paper is a perspective review, not a systematic review. Even so, a paper attempting to adjudicate whether Morgellons is a delusional disorder cannot omit the largest population-based investigation and still present a balanced evidentiary account. Pearson is not the final word. It is an unavoidable one.

What Pearson can—and cannot—answer

It can answer: what investigators found in a defined Northern California population using the study’s broad case definition.

It cannot answer: whether every narrowly defined, tissue-verified filament presentation has the same cause—or whether every person using the Morgellons label has a delusional disorder.

The Pimozide Result Is Reversed

Question 4: Does treatment response support the presence of a delusional belief?

The review says the only randomized, double-blind, placebo-controlled pimozide study improved itching but did not alleviate delusions of infestation or prevent excoriation. It cites two sources: the 1982 Hamann and Avnstorp trial and the 2014 Generali and Cada summary.

Both contradict the sentence.

Hamann and Avnstorp reported improvement in ten of eleven patients, significant relief of both itch and delusions, and a significant reduction in Brief Psychiatric Rating Scale scores. Generali and Cada concluded that the evidence—primarily case series and reports—showed efficacy in the majority of patients.

This is not one defensible interpretation competing with another. The review’s negative claim has no source left standing behind it: both of its own footnotes say otherwise.

The correction must not be exaggerated in the opposite direction. The trial enrolled only eleven people, was published more than four decades ago, and studied delusions of infestation—not a cohort selected for tissue-verified Morgellons fibers. It does not establish that pimozide treats Morgellons. It does establish that the review misstates the result it cites. The surrounding treatment discussion appropriately notes response heterogeneity; the problem is this specific reversal, not the entire section.

The citation trouble continues in the next paragraph. The review attributes a 14-patient follow-up—seven in remission for 19–48 months and four poor responders—to reference 38, an ethics and consent perspective by Söderfeldt and Gross. That paper is not the cohort. The result comes from Lindskov and Baadsgaard’s 1985 follow-up: seven remained in remission, three had relapses controlled with intermittent treatment, and four responded poorly.

One more error is smaller but revealing. Reference 31 dates the Lepping systematic review to 2017. The paper was published in 2007. A ten-year error on a treatment citation would be minor in isolation; beside a reversed trial and a mismatched cohort, it becomes evidence that the treatment references were not checked carefully enough.

Why the correction does not prove pimozide treats Morgellons

The randomized study involved eleven patients with delusions of infestation. It did not recruit a tissue-verified Morgellons cohort. Correcting the review’s account restores the actual trial result; it does not transfer that result to a different patient population.

“Reliable Detection” Comes From One Research Network

Question 3: Can selected positive findings support a universal etiologic claim?

The review states that when sufficiently sensitive testing is used, Lyme disease, relapsing-fever borreliosis, or another tick-borne infection will be detected in Morgellons patients. The sentence is footnoted solely to references 2, 11, 22, and 25–27—all prior papers by Middelveen, Fesler, Stricker, or Savely.

That is a fact about the citation chain, not a judgment about the authors’ motives. It means the review presents a universal claim without independent replication.

Descriptive results from a selected cohort without matched controls—not a prevalence estimate for all Morgellons patients.

The underlying studies are worth reading, but their designs do not justify reliably detected as a rule for all Morgellons patients. A 2010 clinical cohort selected 122 patients for observed fibers and compared their reported features with those of Lyme patients; it was not a controlled test of infection prevalence in Morgellons. A 2015 study of 25 selected patients reported Borrelia DNA or in-situ hybridization positivity in 24. It did not include a matched external control group. A 2018 study of 30 patients reported 63% seroreactivity, 53% PCR positivity, and 90% positivity by at least one Borrelia method—high figures, but not universal detection and again without a matched control group. Its disclosures identify an IGeneX laboratory director and the owner of a tick-borne-disease practice among the authors. A separate 2018 clinical cohort began with 1,000 patients already seropositive for Lyme disease and found Morgellons in 60; because Lyme seropositivity was the entry condition, it cannot estimate Lyme prevalence among Morgellons patients.

Overlapping authorship does not invalidate data. It does limit what can be called replicated, especially when the claim expands from positive findings in selected cohorts to infection will be found in the condition. We examined that broader problem in “The Closed Loop: When Lyme Advocacy Stops Questioning Itself”. Here the narrower point is source discipline: the certainty of the sentence exceeds the independence and reach of the evidence attached to it.

The review declares no conflicts of interest, while separately disclosing that the Charles E. Holman Morgellons Disease Foundation paid the publication fees and thanking several figures associated with Lyme and Morgellons advocacy. Advocacy funding is not automatically a conflict of interest in the strict disclosure sense. But a no-conflict declaration sitting alongside advocacy funding is context readers should be given, particularly in a perspective that relies heavily on the authors’ own research program.

Why 90% is not “reliably detected” in Morgellons

The 90% figure came from a selected 30-patient cohort and combined serologic evidence of exposure with molecular evidence. It was neither 100% nor derived from a population-based, independently replicated study with matched controls.

The Antibiotic Claim Has the Same Source Problem

Question 3: Does improvement identify the cause—and does the cited paper document the improvement?

The review says many Morgellons patients have achieved complete remission with antibiotics alone. It cites its own earlier work, reference 33, and a personal communication from two of the review’s authors.

Reference 33 is Robles and colleagues’ 2011 three-patient case series. It contains no antibiotic-remission cohort. More than that, the paper argues that Morgellons is similar to delusions of parasitosis and states that available evidence did not support an unknown infectious agent as the cause.

The review therefore recruits a source that both lacks the claimed treatment cohort and argues against the etiologic position for which it is being cited. This is the antibiotic mirror of the pimozide problem: a treatment claim rests partly on a source that does not support it. The personal communication is not independently auditable.

Antibiotic response could be important evidence if documented prospectively with defined entry criteria, treatment regimens, objective outcomes, durability, and appropriate controls. As presented here, “many” and “complete remission” are stronger than the cited record permits.

Brain Imaging Does Not Supply the Missing Causal Link

Question 4 versus Question 3: A neural correlate of delusional infestation is not evidence of a spirochetal cause.

The review discusses imaging studies that found group-level brain differences in patients diagnosed with delusional infestation, then proposes that the changes might hypothetically be connected to spirochetal infection. The word hypothetically is doing essential work. The cited imaging studies did not test Morgellons patients for Borrelia and did not establish that infection caused the reported differences.

The imaging findings may help investigate delusional infestation. They cannot be used as a bridge to an infectious etiology without a study that measures both in the same appropriately controlled cohort.

The Folie-à-Deux Speculation Mirrors the Error It Criticizes

Question 4: Whose mental state is actually being assessed?

The review speculates that some clinicians may resist examining specimens because they fear that belief in Morgellons could be transmitted to them, making them participants in a folie à deux.

No evidence is offered for that explanation of clinician behavior. It psychologizes the skeptic instead of testing the skeptic’s conduct—the mirror image of diagnosing a patient from a specimen bag rather than from a psychiatric assessment.

A clinician who refuses to examine relevant material can be criticized on observable grounds: incomplete assessment, premature closure, or failure to document. Inventing an unmeasured fear adds nothing. Symmetric skepticism means not assigning hidden psychopathology to either side when a simpler, testable criticism is available.

A diagnosis of delusion cannot rest on refusal to look. A diagnosis of infection cannot rest on refusal to test the claim independently.

Psychodermatology Does Not Have to Mean Dismissal

Psychodermatology is most useful when it rejects false partitions. Skin disease can cause distress. Distress can intensify itch, picking, sleep loss, and attention to bodily sensations. Infection, inflammation, medication effects, substance exposure, neuropathy, and psychiatric illness can coexist. Treating one component does not prove it caused every other component.

For patients, this means a psychiatric consultation should not function as a disposal chute after dermatology loses interest. It should answer Question 4 with the same care that microscopy and laboratory work answer Questions 2 and 3. A 2020 exchange between Patel and Jafferany and Brownstone and Koo shows that this question remains live even within psychodermatology. For advocates, it means psychiatric evidence cannot be rejected categorically while uncontrolled infectious evidence is accepted categorically.

The humane position is also the rigorous one: examine what can be examined, document what is found, distinguish findings from interpretations, and match each treatment to evidence for the condition it is intended to treat.

https://www.youtube.com/watch?v=Fpj2_enAU6Y

What a Decisive Study Would Need

All four questions: The design must prevent evidence from one layer from being used to answer another.

A stronger study would need:

• a prospective case definition that distinguishes reported fibers from filaments verified in tissue;
• standardized collection with contamination controls and documented chain of custody;
• matched dermatologic, delusional-infestation, and healthy comparison groups;
• blinded microscopy, chemical characterization, histopathology, and validated infectious-disease assays;
• psychiatric assessment performed without knowledge of fiber or infection results;
• predefined thresholds for positivity and clinical outcomes;
• independent replication outside the originating clinical and laboratory network; and
• treatment trials that measure objective skin findings, symptoms, beliefs, adverse effects, and durable remission separately.

Such a design could discover that Morgellons is heterogeneous: an infectious dermopathy in some patients, environmental fibers and secondary excoriation in others, delusional infestation in another group, or combinations not captured by today’s labels. That possibility is not indecision. It is one reason a binary verdict is premature.

The Bottom Line

References and primary-source links

1. Middelveen MJ, Fesler MC, Stricker RB. Morgellons Disease and Psychodermatology. Archives of Clinical and Biomedical Research. 2026;10:293–302. doi:10.26502/acbr.50170533
2. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). 2022.
3. Pearson ML, Selby JV, Katz KA, et al. Clinical, Epidemiologic, Histopathologic and Molecular Features of an Unexplained Dermopathy. PLOS ONE. 2012;7(1):e29908. doi:10.1371/journal.pone.0029908
4. Hamann K, Avnstorp C. Delusions of Infestation Treated by Pimozide: A Double-Blind Crossover Clinical Study. Acta Dermato-Venereologica. 1982;62:55–58. PMID: 6175138.
5. Generali JA, Cada DJ. Pimozide: Parasitosis (Delusional). Hospital Pharmacy. 2014;49(2):134–135. doi:10.1310/hpj4902-134
6. Lindskov R, Baadsgaard O. Delusions of Infestation Treated with Pimozide: A Follow-up Study. Acta Dermato-Venereologica. 1985;65:267–270. PMID: 2411090.
7. Söderfeldt Y, Gross D. Information, Consent and Treatment of Patients with Morgellons Disease: An Ethical Perspective. American Journal of Clinical Dermatology. 2014;15:71–76.
8. Lepping P, Russell I, Freudenmann RW. Antipsychotic Treatment of Primary Delusional Parasitosis: Systematic Review. British Journal of Psychiatry. 2007;191:198–205.
9. Middelveen MJ, Bandoski C, Burke J, et al. Exploring the Association Between Morgellons Disease and Lyme Disease. BMC Dermatology. 2015;15:1.
10. Fesler MC, Middelveen MJ, Stricker RB. Clinical Evaluation of Morgellons Disease in a Cohort of North American Patients. Dermatology Reports. 2018;10(1):7660. doi:10.4081/dr.2018.7660
11. Middelveen MJ, Du Cruz I, Fesler MC, Stricker RB, Shah JS. Detection of Tick-Borne Infection in Morgellons Disease Patients by Serological and Molecular Techniques. Clinical, Cosmetic and Investigational Dermatology. 2018;11:561–569.
12. Robles DT, Olson JM, Combs H, Romm S, Kirby P. Morgellons Disease and Delusions of Parasitosis. American Journal of Clinical Dermatology. 2011;12(1):1–6. doi:10.2165/11533150-000000000-00000
13. Savely VR, Stricker RB. Morgellons Disease: Analysis of a Population with Clinically Confirmed Microscopic Subcutaneous Fibers of Unknown Etiology. Clinical, Cosmetic and Investigational Dermatology. 2010;3:67–78. doi:10.2147/CCID.S9520
14. Lai J, Xu Z, Xu Y, Hu S. Reframing Delusional Infestation: Perspectives on Unresolved Puzzles. Psychology Research and Behavior Management. 2018;11:425–432. doi:10.2147/PRBM.S166720
15. Patel A, Jafferany M. Special Consideration for Patients With Morgellons Disease, Even Among Psychodermatology Patients?—Reply. JAMA Dermatology. 2020;156(10):1142–1143.
16. Brownstone ND, Koo J. Special Consideration for Patients With Morgellons Disease, Even Among Psychodermatology Patients? JAMA Dermatology. 2020;156(10):1142.