Can you have both BPD and bipolar disorder?

Yes. Studies find that a meaningful minority of people with one diagnosis also meet criteria for the other. Each needs its own treatment plan.

Is BPD often misdiagnosed as bipolar disorder?

It can be, in both directions, because the conditions share features and are often assessed in a crisis. A longer assessment that looks at timing, triggers and sleep helps to separate them.

Is there a test to tell BPD from bipolar disorder?

No questionnaire can separate them reliably. A test can help you describe the timing and triggers of your mood changes, which is the information a clinician needs.

Updated November 12, 2026 · Free, no account or email

BPD vs Bipolar Disorder: How They Differ

The main difference is timing. In borderline personality disorder, moods shift within hours and usually follow an event, especially in a relationship. In bipolar disorder, episodes of depression or elevated mood last days to weeks, change sleep and energy, and often arrive without a clear trigger. The two can also occur together.

Take the nine-area symptoms test 10-question BPD test (2 minutes)

Side-by-side comparison

	Borderline personality disorder	Bipolar disorder
How long mood shifts last	Hours, sometimes a day or two	Days to weeks, sometimes months
What sets them off	Usually an event, often between people	Often nothing obvious
Sleep and energy	Usually not the main change	Marked change: little need for sleep when elevated
Between episodes	Sensitivity and relationship difficulties continue	Many people return to their usual self
Sense of self	Often unstable	Usually stable outside episodes
Fear of abandonment	Central for many	Not a defining feature
Main treatment	Structured talking therapy such as DBT	Medication, with therapy alongside

Why the two get confused

Both can involve impulsive behaviour, irritability, intense emotion and suicidal thoughts. Someone seen during a short appointment in a crisis can look much the same either way. What separates them is the pattern over months and years, which is why a careful history matters.

Getting this right affects treatment. Mood-stabilising medication is central to bipolar disorder, while the main evidence-based treatment for BPD is psychotherapy.

Checking your own pattern

The in-depth symptoms test asks whether you have had periods of several days with unusually high energy and little need for sleep. If you have, your report highlights bipolar disorder as something to raise with a professional, alongside your nine-area profile.

Check your own experiences

Both tests are free and private. Your answers stay in your browser, and the result is a starting point for a conversation, not a diagnosis.

Take the nine-area symptoms test 10-question BPD test (2 minutes)

Common questions

Can you have both BPD and bipolar disorder?: Yes. Studies find that a meaningful minority of people with one diagnosis also meet criteria for the other. Each needs its own treatment plan.
Is BPD often misdiagnosed as bipolar disorder?: It can be, in both directions, because the conditions share features and are often assessed in a crisis. A longer assessment that looks at timing, triggers and sleep helps to separate them.
Is there a test to tell BPD from bipolar disorder?: No questionnaire can separate them reliably. A test can help you describe the timing and triggers of your mood changes, which is the information a clinician needs.

Related guides

This page is educational and does not replace an assessment by a professional. If you may hurt yourself or cannot stay safe, find crisis support now. How our content and tests are made · Written by Tyr, founder and editor