Bipolar disorder or something else?

Several diagnostic strategies can help distinguish BPD from BD. For BD to be the primary diagnosis, a patient must have had a hypomanic or manic episode. Sustained episodes of elation or extreme irritability without evident stressors suggest BD rather than BPD.¹⁰ According to Gunderson et al,¹⁰ “repeated angry outbursts, suicide attempts, or acts of deliberate self harm that are reactive to interpersonal stress and reflect extreme rejection sensitivity are axiomatic of borderline personality disorder.” In a review of clinical practice, Gunderson¹⁷ found that hypersensitivity to rejection and fearful preoccupation with expected abandonment are the most distinctive characteristics of BPD patients. He suggested that clinicians can establish the diagnosis by asking patients directly if they believe the criteria for BPD characterize them, which also can help a patient to accept the diagnosis.

Finally, during a short hospitalization, it can be helpful to obtain collateral information from the patient’s friends and family or further characterize the time course of symptoms and diagnostic features in the patient’s natural environment. Clinicians who are reluctant to diagnose BPD in an inpatient setting could suggest the presence of borderline traits or discuss the possibility of the BPD diagnosis in documentation (eg, in the assessment or formulation). Doing so would avoid a premature BPD diagnosis and allow outpatient providers to confirm or rule out personality disorder diagnoses over time. It is important to screen patients with BPD for co-occurring axis I disorders, including BD, MDD, PTSD, and substance abuse.

A false-positive BD diagnosis in patients with BPD has serious treatment implications. Antipsychotics, antidepressants, and anticonvulsants have been used to target BPD symptoms such as affective dysregulation, impulsivity, and cognitive/perceptual abnormalities, but no medications are FDA-approved for treating BPD. American Psychiatric Association guidelines recommend symptom-based pharmacologic strategies for BPD,¹⁸ although some researchers believe that these recommendations are out-of-date and not evidence-based.^17,19 Some evidence suggests pharmacotherapy can have modest short-term benefits on specific BPD symptoms, but no data suggest that medication can reduce the severity of BPD or lead to remission.^19-23 Just 1 randomized controlled trial (N = 17) has examined lithium for BPD and found no effect on mood.^11,24

Misdiagnosis of BD in the context of BPD may create unrealistic expectations regarding the potential efficacy of medications for relieving symptoms. Patients may be diverted from potentially helpful psychotherapeutic treatments—such as DBT or mentalization therapy—which evidence suggests can effectively reduce symptoms, the need for additional treatments, and self-harm or suicidal behaviors.^10,17,19 Evidence from long-term longitudinal studies suggests that psychosocial or psychotherapeutic treatment may protect against suicide in BPD patients.²⁵

Table 2

DSM-IV-TR diagnostic criteria for a manic episode