Gender Bias in Clinical Diagnosis of Borderline Personality Disorder and Autism Spectrum Disorder: A Retrospective Cohort Study

Abstract

Background: Autism spectrum disorder (ASD) and borderline personality disorder (BPD) share overlapping clinical features including social cognitive differences, interpersonal difficulties, emotional dysregulation, and alexithymia. The two conditions show different gender prevalence patterns, and it has been suggested that gender bias may exist in diagnostic patterns of ASD and BPD, with females being preferentially diagnosed with BPD instead of ASD. Methods: In this analysis of real-world clinical records from n = 417,752 adults receiving secondary mental health care, we use natural language processing methodology to assess the subsequent incidence of ASD in cohorts diagnosed with BPD and the incidence of BPD in cohorts diagnosed with ASD. To examine the possibility of gender-based diagnostic bias, we assess for an association between gender and the sequence and timing of diagnoses. Results: Results showed substantial rates of concurrent ASD and BPD; the 5-year cumulative incidence of later ASD diagnosis among people with BPD was 3.02% [95% CI: 2.62, 3.43] and of later BPD diagnosis among people with ASD was 3.84% [3.08, 4.60]. Consistent with predictions of unidirectional gender-based diagnostic bias, the typical association between male gender and ASD diagnosis was reduced in cohorts first diagnosed with BPD, whereas the association between female gender and BPD remained in those first diagnosed with ASD. In addition, the interaction between gender and diagnostic sequence was associated with the length of delay between diagnoses, such that women waited longer for an ASD diagnosis (relative to a BPD diagnosis) compared with men. Conclusion: Together, these results provide a number of avenues for future research and highlight the need for clinicians to consider neurodevelopmental assessment for patients diagnosed with BPD, particularly women, in order to investigate and address potential gender-based diagnostic bias. Community Brief Why is this an important issue? Early recognition of autism is important because it allows service users (individuals receiving support from mental health services) to be offered support. It has been suggested that certain groups of service users (particularly women) may wait longer to receive an autism diagnosis. It has also been suggested that they may be more likely to be diagnosed with alternative psychiatric diagnoses before receiving an autism diagnosis. What was the purpose of this study? This study analyzed rates and timing of diagnosis for two conditions: autism and borderline personality disorder (BPD). We asked whether there was evidence that women were more likely to be diagnosed with BPD before receiving an autism diagnosis. We also explored whether women had to wait longer for autism diagnoses after being diagnosed with BPD. What did the researchers do? We analyzed clinical records from over 400,000 patients in a mental health service in London. We analyzed how commonly service users were diagnosed with autism after being diagnosed with BPD (and vice versa), and whether this was more common in women than men. We also analyzed the length of time service users waited between diagnoses, and whether this was longer for women. What were the results and conclusions of the study? Men and women first diagnosed with BPD were equally likely to be later diagnosed with autism. Women waited longer for an autism diagnosis than men if they previously had a BPD diagnosis, whereas men waited longer for a BPD diagnosis (after an autism diagnosis). What is new or controversial about these findings? Our findings are in-keeping with a pattern in which women may receive diagnoses of BPD more readily than autism. This has not previously been demonstrated using service-user data from real-world clinical settings. What are potential weaknesses in the study? Our study used data from a UK mental health service; it is unknown if findings will generalize to other contexts. This study did not include direct assessments with the service users involved. As such, service users’ views on which of their diagnoses were most appropriate were not obtained. How will these findings help autistic adults now or in the future? This study suggests that women may be more likely to receive an alternate diagnosis before being diagnosed with autism and may wait longer than men to receive an autism diagnosis. Future research may identify how this disparity can be addressed to ensure all service users are offered appropriate support.