Prevalence, psychiatric comorbidity and treatment of multiple personality disorder in Germany: an analysis based on nationwide claims data, 2012–2021

<b>Introduction:</b> In Germany, there is a lack of recent population-based data regarding the prevalence of multiple personality disorder (MPD; ICD-10: F44.81) and the treatment of individuals with this diagnosis. This study aimed to assess the prevalence, psychiatric comorbidities, and treatment of MPD in Germany.<b>Materials and Methods:</b> Based on nationwide claims data, an observational trend study was conducted. For each year from 2012 to 2021, the proportion of persons with at least one coded MPD diagnosis was determined, stratified by sex, age and region. Additionally, psychiatric comorbidity, psychopharmacotherapy, hospital treatment, and outpatient psychotherapy among persons diagnosed with MPD in 2021 were assessed.<b>Results:</b> From 2012 to 2021, the administrative prevalence of MPD increased by 58.5% (from 4.1/100,000 to 6.5/100,000), with a prevalence peak in 17- to 24-year-olds and a female/male ratio of 6:1. In 2021, 86.4% of individuals with a MPD diagnosis had at least one co-occurring psychiatric diagnosis, with 23.9% having five or more. Top comorbidities were anxiety disorders (73.7%), depressive disorders (60.5%), other personality disorders (38.9%), substance use disorders (18.4%), and eating disorders (15.4%). Regarding pharmacotherapy, antidepressants (47.4%), tranquilisers (31.5%), antipsychotics (28.0%), and opioid analgesics (12.8%) were most frequently prescribed. 44.4% of individuals with MPD received psychotherapy, and 14.2% underwent psychiatric hospitalisation (median duration: 7 weeks).<b>Discussion:</b> In this study, we found an administrative prevalence of MPD of 4.1/100,000 in 2012 and 6.5/100,000 in 2021. These figures are considerably lower than those found in epidemiological studies, indicating underdiagnosis of MPD in Germany. The increase in MPD diagnoses was mainly due to a surge in outpatient diagnoses. Individuals with MPD diagnoses had high psychiatric comorbidity, especially depression, anxiety, and personality disorders. Therapeutic measures were in line with current guidelines, with the exception of above-average opioid analgesics prescriptions, which may be related to the high BPD comorbidity.