PS02 Efficacy of antipsychotics in delusional infestation

The 2022 British Association of Dermatologists’ (BAD) guidelines suggest the use of low doses of second-generation antipsychotics as the first-line pharmacological treatment option for adults with delusional infestation (DI). We evaluated the treatment responses associated with different antipsychotics in patients with DI. We undertook a multicentre, retrospective observational study using anonymized electronic patient records from two hospitals in the UK from 1 January 2011 to 1 January 2023. Eligible participants were adults (≥ 18 years) diagnosed with DI treated with an antipsychotic, and had both an assigned baseline and follow-up Clinical Global Impression Scale (CGI-S) score. Participants were excluded if they had known limited or nonadherence to an antipsychotic, or if no CGI-S scores were present at follow-up. First clinic visits before the initiation of an antipsychotic were assigned as the baseline CGI-S score. The last available CGI-S score before the patient either changed antipsychotic or left the clinic for any reason was used to assign the follow-up CGI-S score. The primary outcome was the response to each individual antipsychotic treatment, measured by the difference in the baseline and last available follow-up CGI-S scores. Differences in CGI-S changes between antipsychotic episodes were tested by Anova. In total, 414 patient records were analysed, and data were extracted. The mean age was 61.8 years (SD 14.1). Overall, 170 (41%) of the 414 patients were men and 244 (59%) were women. In total, 156 (38%) of 414 patients were eligible, yielding a total of 315 antipsychotic prescribing episodes. The Anova, ranking in order of treatment response, showed that the highest mean scores (expressing highest treatment response) were observed for amisulpride and risperidone, followed by some distance by quetiapine, aripiprazole and olanzapine (Table). In conclusion, amisulpride and risperidone were associated with a higher treatment response than quetiapine, aripiprazole and olanzapine, and should therefore be considered the first-line treatment options in patients with DI. We thank the BAD for sponsoring this study.TableDifferences in CGI-S scores between baseline and follow-up; data presented as n (%)Risperidone (n = 167)Aripiprazole (n = 46)Amisulpride (n = 46)Olanzapine (n = 28)Quetiapine (n = 25)Chlorpromazine (n = 1)Total (n = 313)+12 (1.2)5 (11)1 (2)1 (4)3 (12%)012 (3.8) 070 (41.9)28 (61)14 (9)20 (71)13 (52)1 (100%)136 (44.9)−161 (36.5)9 (20)