Conference Coverage

Delusional infestation surges during COVID-19 pandemic



Psychiatrists with expertise in delusional infestation have some advice for dermatologists, infectious disease specialists, and primary care physicians who encounter affected patients: If you want to try to help them, initiate treatment yourself.

Peter Lepping, MD, consultation-liaison psychiatrist at Bangor (Wales) University

Dr. Peter Lepping

“If you see it, try and treat it. These patients are unlikely to agree to see a psychiatrist,” Peter Lepping, MD, said at the Entomology 2020 annual meeting.

Indeed, one of the hallmarks of delusional infestation (DI) is a refusal to even consider referral to a mental health professional, noted Dr. Lepping, a consultation-liaison psychiatrist at Bangor (Wales) University who, together with an infectious disease specialist, codirects one of the world’s few DI multispecialty referral clinics, located at the University of Liverpool School of Tropical Medicine.

That being said, he offered another piece of advice: “Accept that it is not easy to help these patients.”

Dr. Lepping was among a group of distinguished psychiatrists, dermatologists, entomologists, and a neurologist at the annual meeting who participated in a comprehensive session devoted to DI. The experts shared tips on making the diagnosis, establishing the rapport necessary to persuade affected patients to try taking a very-low-dose antipsychotic agent for their delusion, and how to achieve a high rate of therapeutic success. They also highlighted recent research advances in the field, including brain MRI evidence suggesting that impaired somatosensory neural networks mediate symptoms in DI, but not in nonsomatic delusional disorders.

COVID-19 pandemic triggers surge in DI

Entomologist Gail E. Ridge, PhD, has taken notes on all of her thousands of consultations with individuals with suspected DI since the late 1990s. A sharp jump in such contacts occurred during the Great Recession of 2008 in conjunction with the widespread social distress of job loss and threatened economic ruin. Now the same thing is happening as the catastrophic COVID-19 pandemic stretches on. Indeed, during the first 8 months of the pandemic she documented 500 interactions involving people with suspected DI. She’s learned to identify the clues, including a chattering mind, defensiveness, physician avoidance, and rigid body tension.

Gale E. Ridge, PhD, director of the Insect Information Office at the Connecticut Agricultural Experiment Station, New Haven, Conn. Courtesy Dr. Gale E. Ridge

Dr. Gale E. Ridge

“They’re fearful of judgment and suggestions of madness. And they’ll pounce on any perceived negativity. I never debunk beliefs; that can immediately backfire. If the medical profession was educated about DI, then many cases could be caught early. I, as the entomologist, and the mental health professionals are often last in line to be seen,” said Dr. Ridge, director of the Insect Information Office at the Connecticut Agricultural Experiment Station in New Haven.

She has noticed a recurring theme in her interactions with these patients: DI often starts with a real underlying medical condition, such as, for example, a cutaneous drug reaction, which over time, progresses to gain a psychiatric component. And she has found that a tipping point often occurs after roughly 6 months of unrelieved symptoms and sensations. Prior to that, affected individuals are concerned about their condition and will seek medical help in a genuine effort to understand what’s going on. They can be redirected. After about 6 months, however, Dr. Ridge has observed “they slide into the rabbit hole of fanaticism and despair.”


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