Drug Use Common in Patients with Delusional Infestation

MedicalResearch.com Interview with:

Dr Anthony Bewley FRCP Consultant Dermatologist Whipps Cross University Hospital & The Royal London Hospital

Dr Anthony Bewley

Dr Anthony Bewley FRCP
Consultant Dermatologist
Whipps Cross University Hospital
& The Royal London Hospital 

MedicalResearch.com: What is the background for this study?

Response: Delusional infestation (DI) is a very disabling condition, whereby patients hold a fixed, unshakeable false belief of being infested with insects or other inanimate objects such as fibres and threads.

Previous studies have indicated a high rate of recreational drug use amongst patients with delusional infestation (DI).

The aim of our pilot study was to look at the prevalence of recreational drug use in patients with delusional infestation who attended clinic over a three year period (Group 1). We also prospectively offered a urine drugs test to 24 consecutive patients over a three month period (Group 2).

MedicalResearch.com: What are the main findings?

Response: Of the 86 patients with delusional infestation (Group 1) who attended clinic over a three year period, 22.1% (19) patients had documented use of recreational drugs in their medical notes. Of the 24 patients offered a urine test (Group 2), 75% (18 patients) accepted, the 25% (6 patients) remaining agreed to do so after counseling but did not do so. Of the 18 urine samples collected, 6 (33%) tested positive, with cannabis being the most prevalent drug. Two patients who denied taking recreational drugs during clinical consultation had positive urine drug test results (8%, Group 2). The mean age of patients at diagnosis was younger for those patients who used recreational drugs (45 years) compared with those who did not (58 years).

MedicalResearch.com: What should readers take away from your report?

Response: Drug use is common in patients with Delusional infestation, particularly among younger patients with DI, suggesting that drugs may have a role in inducing DI at a younger age. Furthermore there may be different aetiologies for the disease in younger compared to older patients. Our pilot study indicates that a number of patients with DI do not disclose taking recreational drugs to medical professionals. Therefore we find routine urine screening of all of our patients necessary. Furthermore, managing drug use may have a role to play in treating patients with Delusional infestation.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

Response: This pilot study should act as a platform for future research into DI, a condition increasing in international public health significance to the medical world. We were unable to conclusively demonstrate whether drug use precipitates Delusional infestation and the answer to this question would help address this public health issue. 

Disclosures: Nothing to declare

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Marshall, C. L., Williams, V., Ellis, C., Taylor, R. E. and Bewley, A. P. (2017), Delusional infestation may be caused by recreational drug usage in some patients, but they may not disclose their habit. Clinical and Experimental Dermatology, 42: 41–45. doi: 10.1111/ced.12999

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Last Updated on January 10, 2017 by Marie Benz MD FAAD