The fundamental problem with evaluating bipolar disorder with other mental disorders is the lack of a clear roadmap for accurate differential diagnosis. As I have written before, nearly two-thirds of people with bipolar disorder have been misdiagnosed at least once in their lifetime, and on average they will see nearly four specialists before receiving a correct diagnosis of bipolar disorder. Perhaps most troubling is the length of time it takes for an individual to receive a bipolar diagnosis and appropriate treatment.
The average time from the moment a person experiences their first bipolar episode to receiving treatment for bipolar disorder is about 10 years. This gap in treatment is the result of a profound misunderstanding of what bipolar disorder is, how it manifests in episodes that can come and go, and a general reticence to discuss the existence of a chronic mental illness, especially when symptoms are present in a young person. While most people with bipolar disorder are misdiagnosed with non-bipolar major depression, many are misdiagnosed with a personality disorder. Indeed, a person with bipolar disorder may also have a co-occurring personality disorder, but these classifications are often confused and cause treatment complications as a result.
Some personality disorders can mimic behavioral signs within bipolar mood swings, especially in the areas of manic mood. Borderline, narcissistic, and antisocial personality disorders can have some of the closest similarities to the more prominent aspects of bipolar disorder. In this post, I will focus specifically on borderline personality disorder and how to better differentiate it from bipolar disorder.
Individuals with borderline personality disorder typically exhibit extreme emotional changes, disturbed relationship patterns, and irresponsible or risky interpersonal behaviors. A key component of borderline personality disorder is called idealization/devaluation or splitting. This means that a person with borderline personality disorder may idealize another person in a relationship (including the therapist during treatment) as “perfectly good” or the “perfect soulmate.” Later, and usually without apparent provocation, this same amazing person will be devalued by the borderline person as “totally bad” or “useless.” This radical shift in perception, emotion, and behavior toward others is the hallmark of the borderline personality.
But extreme instability in mood, relationships, and social behavior can seem crazy, and can easily be confused with bipolar disorder. Any distinction between the two disorders is complicated by the fact that people with borderline personality disorder can experience severe depression with suicidal thoughts and actions in the same way that people with bipolar disorder can. But while mood instability is an ongoing problem with borderline personality, the mood swings in bipolar disorder come and go with periods of basic stability. People with borderline personality also have an intense fear of abandonment in relationships, which can certainly happen to people with bipolar disorder but is not in itself a feature of bipolar disorder. The first major distinction between these diagnoses is that bipolar disorder is a primary mood disorder and borderline disorder is a primary personality disorder that involves long-term interpersonal dysfunction. As a result, bipolar disorder manifests itself in mood episodes that can change rapidly or in long periods, with periods of apparent equilibrium in between, referred to as the core mood zone. Therefore, the symptoms of bipolar disorder are intermittent. In contrast, borderline personality is pervasive, with symptoms and functional consequences of the disorder being persistent across mood states. This may seem misleading to some who have seen people with BPD appear happy, calm, or having a “good day,” as the primary mood zone of bipolar type. But while immediate behavioral signs may indicate a stable mood state, the pervasiveness of borderline personality often reflects a tangled, ongoing mess of interpersonal relationships and self-image, regardless of the mood state present.
So while mood instability and interpersonal conflicts can be prominent in both bipolar disorder and borderline disorder, the differences begin in the origins of symptoms and their behavioral consequences. One way to approach this is to ask, “What is the underlying aspect of the particular disorder that drives the byproduct?” Bipolar disorder is a mood disorder, genetically inherited, that affects the brain’s ability to regulate emotion. Bipolar mood swings have serious consequences for the person with the disorder, including increased impulsivity and personality disturbances.
The mood instability in BPD may be more reactive and after the internal and personality disorders driven by a deep-seated fear of abandonment, along with intense feelings of emptiness and alienation. While these factors do not entirely rule out some genetic link between BPD and personality, psychosocial and developmental factors appear to dominate the etiology of BPD. Indeed, the fear of abandonment pervades BPD behavior to the extent that it can govern essentially every shift in mood and action, as seen in the ego defense of splitting, which reduces the value of others to objects that can be easily divided into idealized and devalued parts. The primary goal of splitting is to fill the feeling of emptiness through idealization and over-identification with the other (or object), while controlling the anxiety of perceived inevitable abandonment by devaluing the other, often with a great deal of hostility.
Stress and anxiety, including fear of abandonment, can certainly influence mood episodes in bipolar disorder. However, this would serve as a trigger for the underlying, predisposed nature of the neurological changes that govern mood episodes and would be only one of many possible triggers, including those of both internal and external origin. Anxiety in someone with borderline personality disorder, and responses to it including self-harm, suicidal gestures, erratic spending, excessive sexual desire, or outbursts of anger, stem from fear embedded in the context of interpersonal and ego dysfunction. Since splitting is a primary ego defense in borderline personality disorder, denial appears to be a more dominant defense in bipolar disorder. Indeed, if splitting is persistent in someone with a clear diagnosis of bipolar disorder, there is a reasonable possibility that borderline personality coexists with bipolar disorder in general.
Another factor that may help separate these diagnoses relates to onset. The average age of onset for bipolar disorder is 18 years, which means that children may show signs of the disorder early in life, and may have expressed early symptoms before the full spectrum of symptoms that meet DSM-5 criteria appear in adulthood. There is no average age of onset for borderline disorder per se; in fact, the long-term nature of this personality disorder means that diagnosis requires active and persistent symptoms into adulthood. Certainly, some adolescents may display borderline traits that may eventually coalesce into a borderline diagnosis, but this is not in itself a reliable indicator of diagnosis later in life. However, mood instability in bipolar disorder can often be traced back to childhood, especially if it is significantly caused by hormonal changes in adolescence and does not stabilize in early adulthood. The overlap between bipolar and borderline symptoms may seem to suggest that treatment approaches will be similar, but this is usually not the case. While I believe that both disorders require extended psychotherapy services, especially in an individualized setting, there are some important differences to consider. In bipolar disorder, pre-stabilization treatment focuses on the immediate crisis caused or exacerbated by bipolar mood swings, working through denial toward acceptance of bipolar disorder, and any internal struggles related to initiating bipolar medication trials toward stabilizing mood. In borderline personality, building trust in the therapeutic alliance is often the top priority, especially given the individual’s pattern of personal instability. It is not that people with bipolar disorder do not need a strong experience of trust in treatment to move forward; however, with borderline personality patients, building and maintaining trust and stability in the therapeutic alliance is critical to any reasonable diagnosis of improved self-image, frustration tolerance, and personal functioning. Even then, it may take months or years of consistent treatment before such improvements become sustainable.
As a person with bipolar disorder progresses through stability toward post-stable, treatment can increasingly focus on the pre-functioning consequences of the disorder (e.g., financial distress, extramarital affairs, substance abuse, etc.). This progression can make treatment more broadly effective about relevant life issues and allow other therapies, such as couples therapy, to be more adaptive to specific life struggles. In treatment for borderline personality disorder, the increased sense of dependence on the therapist as a reliable figure often reignites deep-seated fears of abandonment, reinforcing ego defenses, paranoid projections, and unconscious reenactments of trauma, all of which can recur throughout treatment. The therapist treating a patient with borderline personality disorder must anticipate and prepare for these traits when they manifest in the phenomenon of transference. Another reason to distinguish between bipolar disorder and borderline concerns medication issues. Mood-stabilizing medications, such as lamotrigine, are generally effective in bipolar disorder but are not consistently effective in borderline personality disorder. But, understandably, a doctor might prescribe mood stabilizers instead of antidepressants, especially if he or she is concerned about bipolar disorder in someone with early symptoms of borderline personality disorder. This is because antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), can act as manic triggers in people with bipolar disorder, especially if a mood stabilizer is not already in the treatment regimen. Doctors may also consider atypical antipsychotic medications if there is no clear distinction between symptoms of borderline personality disorder and bipolar disorder, especially if there is suspected evidence of psychosis. While it may be true that drug treatment for borderline personality disorder is generally more complex than for bipolar disorder, a clearer diagnostic picture can help doctors open up a wider range of treatment options for these disorders, whether distinct or co-occurring.
