Misdiagnosis of borderline personality disorder

Borderline personality disorder (BPD) is a personality disorder characterized by a pervasive, long-term pattern of significant interpersonal relationship instability, a distorted sense of self, and intense emotional responses, which can be misdiagnosed. Misdiagnosis may involve erroneously assigning a BPD diagnosis to individuals not meeting the specific criteria or attributing an incorrect alternate diagnosis in cases where BPD is the accurate condition.

Alternative diagnoses
Misdiagnosis of borderline personality disorder (BPD) can occur due to symptom overlap with other mental health conditions and the high rate of comorbidity in personality disorders. Research has shown that having a personality disorder like BPD is a significant vulnerability factor for comorbidity with other mental health conditions. The mood instability characteristic of BPD often leads to confusion with bipolar disorder. Furthermore, the significant role of trauma in BPD complicates its distinction from complex post-traumatic stress disorder (C-PTSD) or post-traumatic stress disorder (PTSD), adding to the challenges of accurate diagnosis.

Complex post-traumatic stress disorder
Complex post-traumatic stress disorder (C-PTSD), recognized in the ICD-11 but not in the DSM-5, shares core features with BPD, such as emotional dysregulation, interpersonal difficulties, and a negative self-concept, complicating their differentiation. Unique manifestations of these symptoms in C-PTSD and BPD can aid in distinguishing between them; for instance, C-PTSD often involves reactive anger or substance use, while BPD is more associated with self-injury or suicidality. Relationship instability in BPD typically involves rapid shifts between idealization and devaluation, whereas in C-PTSD, it stems from difficulty forming close connections. Additionally, while individuals with BPD may experience fluctuating self-concepts, those with C-PTSD usually maintain a consistently negative self-image. Understanding these differences is crucial for clinicians to accurately diagnose and differentiate between C-PTSD and BPD, especially when comorbid with PTSD, underscoring the importance of comprehensive evaluations.

Bipolar disorder (BD)
Bipolar disorder (BD), a mood disorder characterized by significant mood swings, is categorized into bipolar I, involving at least one manic episode, and bipolar II, characterized by at least one hypomanic and one depressive episode. Both BD and BPD exhibit overlapping features, making differential diagnosis challenging. Affective instability and negative affectivity are core features of both disorders, albeit with variations in their nature and longevity. The difficulty in controlling anger in BPD and the presence of irritability in BD might not be easily differentiated. Impulsivity is a common trait in both conditions; however, in BD, impulsivity may diminish between mood episodes. Additionally, both disorders are characterized by high rates of suicidality and similarly impact social functioning. A small study of 700 participants showed that diagnostic criteria for BPD put patients with BPD at risk of being misdiagnosed with BD, as it found that 40% of those diagnosed with BPD report having been misdiagnosed with BD.

Consequences of misdiagnosis
Misdiagnosis of BPD can result in a number of negative consequences. The reasoning for diagnosis is that of debate within the mental health field. Still, it is primarily looked at as serving the function of providing health professionals of the patient's mental health state, to inform treatment approaches, and to aid in accurately reporting successful treatment approaches. Therefore, misdiagnosis can result in outcomes such as not having access to appropriate psychiatric medications or not being provided evidence-based psychological treatment for their disorders.

Medical
As diagnosis is an essential part of determining what medications to prescribe to a patient or if a patient would benefit from psychopharmacotherapy, being misdiagnosed can have a range of adverse outcomes. Current research has indicated while some prescription medications can help with specific symptoms of BPD, there is no medication proven to decrease BPD symptoms as a whole. In contrast, disorders such as bipolar disorder (BD) have a range of psychiatric medications (e.g., Lithium, anticonvulsants, GABA analogs) being used as a first-line approach to treatment. By providing people with BPD with misdiagnoses such as BD, people with BPD can be subject to receiving medications that will not impact their symptomology and may result in adverse side effects. Alternatively, people who are diagnosed with BPD who may instead have BD or C-PTSD (complex post-traumatic stress disorder) may be deprived of psychopharmacological interventions that would decrease symptoms severity.

Psychological
Misdiagnosis of BPD can also result in adverse psychological consequences as a diagnosis is used in determining evidence-based treatment approaches used in the therapeutic setting. Treatment approaches such as dialectical behavior therapy and cognitive behavioral therapy for borderline personality disorder are two evidence-based treatments shown to be effective in the treatment of BPD. By providing a misdiagnosis, a person with BPD would likely not have access to these specific treatment approaches, and therefore, their access to evidence-based treatment for their BPD would be delayed until an accurate diagnosis is given.