Yes, you can have both borderline personality disorder and bipolar disorder diagnosed at the same time
A person can meet the diagnostic criteria for both borderline personality disorder (BPD) and bipolar disorder. This is called comorbidity. The two conditions are separate diagnoses with different underlying patterns, but they can occur together in the same person. Having both does not mean one diagnosis is wrong—it means both are present and both need to be addressed in treatment.
The confusion happens because some symptoms overlap: both conditions involve mood changes, impulsivity, and emotional intensity. But the timing, triggers, and pattern of these symptoms are different enough that a clinician trained in both conditions can distinguish them. Getting both diagnoses right matters because the treatment approach changes depending on which conditions are actually present.
Key Takeaways
- BPD and bipolar disorder are separate conditions that can both be diagnosed in the same person, though this is less common than having one or the other alone.
- Bipolar disorder involves distinct mood episodes (depression, mania, or hypomania) that last days to weeks; BPD involves rapid mood shifts within hours that are usually triggered by relationships or perceived rejection.
- A clinician needs to track the actual pattern of your moods over time to tell them apart, not just hear a description of mood changes.
- Treatment differs: bipolar disorder typically requires mood stabilizers or antipsychotics, while BPD treatment focuses on therapy and sometimes different medication classes.
- If you have received one diagnosis but symptoms do not match the treatment response, asking for a second evaluation from a clinician experienced in both conditions is reasonable.
How the mood patterns actually differ
Bipolar disorder produces distinct episodes. A manic or hypomanic episode lasts at least several days (mania) or at least four consecutive days (hypomania). During that time, your mood is elevated or irritable, your energy is noticeably higher, you need less sleep, your thoughts race, and you may take risks you normally would not. When the episode ends, it ends—you return to a baseline. A depressive episode in bipolar disorder lasts at least two weeks and involves low mood, fatigue, sleep changes, and difficulty concentrating.
BPD produces rapid mood shifts within the same day, often triggered by something specific: a perceived slight from a partner, a cancelled plan, a text that feels rejecting. The shift is intense but usually lasts hours, not days. You might feel abandoned and suicidal in the morning, then calmer by afternoon. The mood changes are reactive—they respond to events or relationships—rather than coming from an internal biological cycle. Between these shifts, your baseline mood may be chronically empty or anxious rather than stable.
A clinician distinguishes them partly by asking you to track your mood over weeks: Do your mood changes follow a predictable internal rhythm, or do they spike in response to specific events? Do episodes last days or hours? Do you have periods of normal mood in between, or is your mood always somewhat unstable?
Why both diagnoses can be present
Having both conditions means you experience the distinct mood episodes of bipolar disorder and the rapid, relationship-triggered mood shifts of BPD. This is uncommon but documented. Some research suggests that people with bipolar disorder may be more likely to also have BPD traits, though the exact overlap rate varies depending on how strictly clinicians apply the diagnostic criteria.
One reason the overlap exists is that both conditions involve emotion regulation problems, though through different mechanisms. Bipolar disorder is a mood cycling condition rooted in neurobiology. BPD is a condition of intense, unstable emotions and relationships. A person can have both the biological cycling and the relational sensitivity.
Another reason clinicians sometimes miss the comorbidity is that one diagnosis can overshadow the other. If someone is hospitalized during a manic episode, the bipolar diagnosis becomes the focus and BPD traits may not be assessed. Or if someone is in therapy for relationship instability, the slower-moving bipolar episodes might be attributed to stress rather than recognized as separate.
What happens in treatment when both are present
If you have both diagnoses, your treatment plan needs to address both. Bipolar disorder typically requires a mood stabilizer (like lithium or valproate) or an antipsychotic medication. These are chosen based on whether you have more depressive or manic episodes and how severe they are. BPD does not respond well to mood stabilizers alone; the primary treatment is psychotherapy, particularly dialectical behavior therapy (DBT) or mentalization-based therapy.
This means you might be on a mood stabilizer for the bipolar component while also in structured therapy for the BPD component. Some medications used for bipolar disorder—particularly certain antipsychotics—may help with impulsivity and anger in BPD as well, so there can be some overlap in what helps. But the therapy piece is essential for BPD and is not the primary treatment for bipolar disorder.
A psychiatrist experienced in both conditions will monitor whether your medication is controlling the bipolar episodes while your therapy addresses the relationship patterns and emotion regulation that BPD involves. If you are on medication but still having rapid mood swings triggered by relationships, that suggests the BPD component is not being treated. If you are in therapy but still having distinct manic or depressive episodes, the bipolar component may need medication adjustment.
How to know if you might have both
If you have been diagnosed with one condition but the treatment is not working as expected, it may be worth exploring whether the other is also present. Some signs that both might be present include: you have distinct episodes of depression or mania that last days or weeks, and you also have rapid mood shifts within hours that are triggered by relationship events or perceived rejection. You respond partially to mood stabilizers but still struggle with intense, unstable emotions. Your mood episodes seem to follow a pattern independent of what is happening in your life, but you also notice your mood spikes sharply when someone upsets you.
Getting a second evaluation from a clinician who has experience diagnosing both conditions is a reasonable step. Bring a mood log or journal if you have one—actual data about when your moods shift and what happened before the shift is more useful than memory alone. Be specific about the timing: Do your mood changes last hours or days? Do they happen without an obvious trigger, or does something always precede them?
Why the distinction matters for your care
Misdiagnosis in either direction has real consequences. If you have bipolar disorder but are diagnosed only with BPD, you may not receive mood stabilizers you need, and your episodes may worsen. If you have BPD but are diagnosed only with bipolar disorder, you may be on medication that does not address the core problem—your relationship patterns and emotion regulation—and therapy may be deprioritized.
Getting both diagnoses right also affects how you understand yourself. Bipolar disorder is a condition where your brain chemistry cycles in ways you cannot control through willpower or therapy alone. BPD involves patterns in relationships and emotion regulation that therapy can directly change. Both are real. Both require treatment. But the treatment is different, and knowing which you have helps you know what to expect and what will actually help.
Frequently Asked Questions
If I have BPD, does that mean I will develop bipolar disorder later?
No. BPD and bipolar disorder are separate conditions. Having one does not mean you will develop the other. However, if you have both, they were likely present at the same time, not one developing from the other. If your symptoms change significantly over time, that is worth discussing with your clinician, but BPD does not transform into bipolar disorder.
Can medication for bipolar disorder make BPD worse?
Mood stabilizers and antipsychotics do not typically make BPD worse, but they may not fully address BPD symptoms either. If you are on bipolar medication and still struggling with relationship instability, impulsivity, or rapid mood shifts triggered by events, that suggests you need the BPD-specific treatment (therapy) in addition to medication. The two treatments work on different parts of the problem.
How long does it take to get an accurate diagnosis if both are present?
It depends on how carefully the clinician tracks your symptoms over time. A single appointment is usually not enough to distinguish them. Most clinicians need to see a pattern over weeks or months—either through your own tracking or through multiple visits. If you are seeing someone new, bringing a mood log from the past few months can speed up the process.
Is one diagnosis more serious than the other?
Both are serious conditions that benefit from treatment. Bipolar disorder can involve severe episodes that require hospitalization. BPD involves high rates of self-harm and suicide risk. Having both means you need comprehensive treatment addressing both the mood cycling and the relationship and emotion regulation patterns. Severity depends on the individual, not on which diagnosis you have.
What if my clinician says I cannot have both?
Some clinicians are less familiar with comorbid BPD and bipolar disorder and may dismiss one diagnosis. You can ask them to explain why they think only one is present, or you can seek a second opinion from a clinician who specializes in personality disorders or mood disorders. Getting the diagnosis right is worth the effort of a second evaluation.