Outcomes for delusional infestation in multidisciplinary clinics

Background Delusional infestation (DI) is a psycho-dermatological illness that often presents to dermatologists. Patients have fixed delusional beliefs that they are infested with living or nonliving pathogens that cause symptoms. Antipsychotic medication is the treatment of choice. Patient engagement is a challenge. Little is known about the best settings in which to treat DI.Objectives We examined outcomes for patients with DI referred to multidisciplinary clinics in the UK, comprising dermatologists or tropical medicine physicians paired with psychiatrists.Methods We used Clinical Global Impression scale (CGI-S) score changes as our main outcome parameter. We report average CGI-S score changes for all groups. We used independent t-tests and an Anova analysis to measure differences between those who had a planned discharge and those who were lost to follow-up (LTFU), separating each group between those who reported taking medication and those who did not.Results Records from 465 patients were reviewed: 94 (20.2%) patients had no CGI-S data points (12.0% did not attend; 8.2% missing data); 151 (32.5%) were followed up and had a planned discharge; 193 (41.5%) were lost to follow-up (LTFU) at some point, of whom 63 patients (13.5%) attended only once and had their last (only) observation carried forward. Of the 281 (60.4%) patients who attended the clinics at least twice, 108 (38.4%) had a response or remission (n = 69; 24.6%). The mean average CGI-S score change was -1.29, indicating clinically relevant improvement. Those who had a planned discharge and reported to have taken medication had an average CGI-S score change of -2.02, indicating significant improvement. Those who took medication but were LTFU had an average CGI-S change of -0.63 (just below clinically relevant improvement); those LTFU who did not take medication did not improve (CGI-S change -0.07).Conclusions Patients with DI who took medication did significantly better than those who did not. Patients who had a planned discharge did significantly better than those who were LTFU. Multidisciplinary clinics have good clinical outcomes for patients with DI, especially where patient engagement was reasonable. People who have delusional infestation believe that they are infested with living or non-living things. It affects about 90 people in a million. Antipsychotic medication can help with this. However, patients with delusional infestation often do not take their medication. They do not believe that they have a psychiatric illness. We know that doctors working together can help patients to engage with treatment. Our research was done across several centres in the UK.We tried to find out how much people with delusional infestation improve if they are seen by a multidisciplinary team. We paired dermatologists or infectious diseases doctors together with psychiatrists. The Clinical Global Impression (CGI) is a standard scoring tool. We used this to find out whether patients with delusional infestation improved or not. On average, patients who came at least twice to the clinics had a two-thirds chance to get better or be cured completely. Those patients who took the prescribed medication did better than those who did not. People who engaged with the clinic and had a planned discharge to other services did better than those who were lost to follow-up in the clinic.Patients with delusional infestation who attend clinics with a team that includes a psychiatrist have a good chance of improving or healing. This works well, especially if they engage with the clinic and take their prescribed medication. We have shown that patients with delusional infestation can be treated successfully in multidisciplinary clinics where psychiatrists work with dermatologists or tropical medicine physicians. Taking their antipsychotic medication and staying engaged with the clinics yield the best results.