Information about the relationship between personality disorder and ethnicity or migration is sparse. The few studies regarding the prevalence of borderline personality disorder (BPD) in immigrants compared to an indigenous population are inconsistent.

The aim of the present study was to compare the frequency of a BPD diagnosis in psychiatric inpatients with and without an immigrant background.

2494 consecutive patients over a 3-year period at a psychiatric university hospital were reviewed. Data included socio-demographic and clinical variables and also information about an immigrant background. The psychiatric diagnosis was limited to information available from the digital documentation system of the psychiatric clinic and additionally from discharge letters. The diagnosis of borderline personality disorder was based on ICD-10 criteria.

374 individuals (15%) of the study population had an immigrant background. The rates of BPD were 6.5% in the indigenous group (n = 2120) vs. 3.5% in the immigrant group (n = 374). The difference between the indigenous and the immigrant group regarding the rates of BPD-diagnoses was statistically significant (chi2 = 5.02, df = 1, p = 0.025).

The findings suggest that in a clinical sample BPD was diagnosed less frequently in the immigrant group than in the indigenous group. Therefore, our results do not support the concept of immigration as a risk factor for BPD. However, future investigations with a prospective study design and at epidemiological levels need to be conducted in order to get more precise information about the prevalence of BPD in different immigrant groups.