Borderline Personality Disorder and Bipolar Disorder: What’s the Difference?

By Ken Duckworth, M.D. | Jun. 12, 2017


Getting the right diagnosis often isn’t easy for psychiatric conditions. In our field, we don’t yet have biologic tests that can easily define one condition from another. If your blood pressure is 140 over 90, you have hypertension or high blood pressure. In mental health, we have to rely on a description of patterns or symptoms to makes diagnoses. This model is fraught with challenges.

Without a clear biological model to work from, and given the complexity of the human brain, the field has settled upon dividing these descriptions of symptoms into syndromes. The Diagnostic and Statistical Manual of Mental Disorders (DSM) holds these symptom descriptions in order to help professionals make reliable and consistent diagnoses. This means a social worker in Detroit should make the same diagnosis as a psychiatrist in Boston and a psychologist in Santa Fe.

However, the diagnostic process is more complex than just reading symptoms in a DSM. Here are a few thoughts on what I have observed in making diagnoses:

  • Diagnosis is best viewed as a movie, not a snapshot. In a snapshot, people with different diagnoses can appear to have similar symptoms. The key is to step back and develop a view of their history and the pattern of symptoms.
  • People may present different symptoms over time, which can change their diagnosis. A person who has a depressive disorder, for example, could have a manic episode a year later. This would change that person’s diagnosis to bipolar disorder. The original diagnosis wasn’t a misdiagnosis—rather the movie changed its storyline and the diagnosis needed to change as well.
  • It’s common to have more than one diagnosis. For many people, there may not be one simple diagnosis. For example, people can have both bipolar disorder and a substance use disorder diagnoses.
  • Medical problems or medications can influence or even mimic symptoms. Hypothyroidism presents with almost all symptoms of depression for example, and steroids can add risk for mood symptoms.
  • Get informed. Patients who know their symptoms can help in the search for a diagnosis. People have brought write-ups to their appointment as they search for answers, and I have referred some people to the DSM-5 so they can evaluate their experience.

Let’s focus on the sometimes-confused conditions of Bipolar Disorder and Borderline Personality Disorder (BPD). In a snapshot, they can look similar—both can present with impulsive behavior, intense emotions and suicidal thinking. But this snapshot is not the best way to tell them apart. It’s really the movie of the symptom presentation over time that can help make the diagnosis distinct.

Classic Bipolar Disorder Type 1 is easier to differentiate from BPD than Bipolar 2. True manic symptoms (often with hallucinations) are the hallmark of Type 1 and these symptoms are not seen in the same way in BPD. Bipolar Type 2 is a more challenging diagnosis to differentiate from BPD, because the classic manic episode is absent. So, on the surface, it can appear more like BPD. Here are a few ways to help tell the difference between bipolar and BPD:

How Often Do Moods Change?

People with Bipolar Type 1 have cycles that switch from a depressive state to a manic state. Manic symptoms sometimes include flashes of deep depression within the manic episode (called rapid cycling). Between cycles, people often have periods of true symptom-free wellness. This period of wellness can last weeks, months or years depending on the person. People diagnosed with BPD typically have more persistent day-to-day emotional symptoms which can impact everyday life. BPD mood changes are more persistent, short-lived and reactive to environmental factors, like stress at work or home.

Is Sleep Normal?

Sleep changes are often an early indicator of a bipolar disorder. During a bipolar episode, a person might be awake for days and not experience fatigue or they may sleep for days. Meanwhile, sleep patterns are less commonly impacted in BPD.

Is There a Family History?

Mood disorders, like bipolar disorder and depression, run in families, but aren’t directly passed on through a single, specific gene. A family history of mood disorders increases the chances of mood disorders appearing in relatives.

Are Relationships Often Unstable?

Intense relationships often fraught with conflict are the hallmark of borderline personality disorder. People with BPD often have intense relationship histories, and many of their experiences with emotional dysregulation (intense reactions and variabilities) are in response to relationship interactions.

Is Self-Harm a Symptom?

Self-harm such as cutting one’s skin is more common in BPD and is thought to be a way to help with emotional regulation. “I’m not suicidal, I was just trying to change my feelings by cutting,” I’ve been told by individuals with BPD. In fact, 75% of individuals with BPD have cut, burned, hit or injured themselves.

Diagnosing a mental illness isn’t like diagnosing some physical illnesses—it takes a lot of observation and understanding to find the right diagnosis. If your diagnosis doesn’t feel right or isn’t clear, it’s best to talk to your clinician. Ask about your diagnosis and treatment plan and be engaged in the diagnostic process. If you and your practitioner aren’t sure, ask for a second opinion. It’s okay not to be sure, and it’s smart to keep learning.

Both BPD and bipolar have good treatment options, but they are very different options, so putting time into getting a correct diagnosis is essential. These are serious health conditions that need individualized support and care in order to optimize recovery.


Ken Duckworth is medical director at NAMI.

AnnMarie Klavins
Informative .
1/2/2018 1:12:53 PM

I was told that I had Borderline Personality Disorder for 20 years. A few doctors thought I was bi-polar, but I stopped going to those doctors! in 2012 I was hospitalized for 9 weeks with daily therapy by a team of therapists, psychiatrists and medical doctors. I told them, "I give up, I'm bi-polar with borderline Personality Disorder!" They said, "we'll see....." WELL... as the article says, it's a movie, not a snap-shot. Long story short, I am NEITHER! I have PTSD. go figure! life has made more sense in these past 5 years than in the 47 years prior (I am 52 years old now.)
12/10/2017 8:01:17 PM

In Virginia where do you go with no insurance? And how do you stop lying about how you've already gone? And also how do we lie so well and why do we do it? Thank you in advance for your time and consideration.
11/14/2017 2:47:56 AM

Great support thank you
11/5/2017 10:56:27 AM

Lori ,Shoemaker
I really wish the whole world would just stop trying to rush everything, even when writing, or texting please just write out the whole word it takes 2extra seconds to write bipolar disorder, or borderline personality seriously people slow down it's hard for people to remember all these abbreviations being thrown around.
7/3/2017 5:13:28 PM

Great info, but I am concerned, my husband I guess is bipolar. But seems to fall in both sides. So I guess this was not so though out. It's seems many real people who have to deal with it on a daily basics seems to see it just someone looking to come up with another DX. something more for insurance and drug companies can just aboard and charge more money for.
People with mental health issues have enough issues in their lives and don't need to be having more meds and being bounced around. They are people not rubber balls.
Sorry to rant, I'm sick of seeing love ones hurt because they feel as those it the "oh look another pill, we can try". How sick can they all get from it?????
7/3/2017 12:14:15 AM

Ronald Kohl
Response to Linda Thomas:
Linda, care-giving family members can often arrange with the patient to talk with the psychiatrist, assist with meds, etc., in exchange for something the patient values. Cooperation brings exchange; no cooperation, no exchange. Attendance at NAMI-affiliate meetings, interacting with people who have been there, can be helpful in determining your own course.
7/2/2017 10:46:35 PM

Alanon has been very helpful to me and available in most areas day and evening for family and friends of alcohol and drug users. These folks have been through it all and can help
7/1/2017 6:32:16 PM

Linda Thomas
In military service, my husband was DX'd as "Personality Disorder" . Discharged, he was DX'd by civilian MD as Bipolar. Thus, med change. Then new psych, new med. change. Thus has gone on 30 yrs now, with disasters from each med change, each psych's opinion. Wish new and old psychs would consult, wish all psychs would consult with person who knows patient well, since these patients lie, and believe their own lies.
6/29/2017 9:37:43 AM

Another excellent article. Spot on
6/28/2017 6:21:16 PM

Kathleen Powers
Can a person have a bipolar diagnosis AND a BPD one?
6/28/2017 4:50:43 PM

kim cook
Hello everyone
I have been dragging my feet getting here I have been trying to get my daughter to come in for some help,I am not have any luck i am completely cut out from her life and my grandson. We were all fine she took off 12/26/16 went to her biological mothers 2 blocks away she is in complete hideout and will not let me see my grandson diagnosed 7/15/16 with disorders at 13. He is taking medication and she has not for 10 yrs. She has bipolar manic aggressive disorder 2 / her bilogical mother has schizophrenia I am just sick about everything I was very sick for several months and did not see the onset of her illness until 1/10/17 she had been walking around preparing her plans for approx 10 months before i seen clearly what had happened . I need some group time. I am moving forward with my court case to have visitation with my grandson and possible guardianship with both
she has been hiding from all servers making things difficult, as of yesterday new information and praying she will have her court papers by Friday. This is the Eugene area correct? I need to find a family group meeting i thought I seen something for Tuesday nights however it said when school was in?? Im going to call the nami phone number in morning for info, unless anyone has info to share now? I plan to be active I just do not no how to handle her at this age 39? and as far out as she has gotten. I am her enemy and was being so aggressive i do not no who she is? and my grandson what is happening to him??
6/27/2017 4:11:14 AM

My experience in my own sickness has been exhausting...I'll be turning 48 this year although a psychiatrist shared with me my BPD almost 8 years ago...I've never plunged for knowledge until now...I thought I was just an overly sensitive person with absolutely no control over my emotions...My 27 year old daughter in my opinion is way worse...I have been thinking she was bipolar until I started paying attention more closely and realized my own "issues" in her...but then I realized she's not had my life's tragedies knock the wind out of her as I have...and knocked me down a level or two...she still has her angry....she still has a violence in her...I'm to tired...I feel like I have to detach from my only child and miss out on my granddaughters...just to save my own strength...Having come to these revelations I've tried reaching out to my shrink to help me navigate and he hasn't returned my call...I'm not going to go into how hurtful that is but....I'll try to find another Dr I guess... It just always seems conspiratorial because my family Dr doesn't get it? Doesn't see it? Always lost and trying to stay buoyant is just such a struggle and a real life *****er
6/25/2017 10:05:42 PM

I would contact your local Community Services Board, Social Services, or if the healthy spouse is elderly, then the Agency for Aging. Surely, the ER wouldn't release the patient if at risk...You could contact the ill spouse's therapist to voice your concerns, knowing that he/she will be unable to discuss the case due to HIPAA. Hope this helps.
6/18/2017 2:14:25 AM

Marina Madden
I need of a advocate for a family caregiver that has a spouse dealing with a disorder.. emergency services needed because they are releasing my family member and I'm worried we are not being supported with confident help!!!
6/15/2017 7:46:30 PM

Claudia Eyre
This is article does an excellent job of summarizing difficult aspects of differentiation between Bipolar Mood Disorder and the much stigmatized and much talked-about Borderline Personality Disorder. While the article provides some clear distinctions, in actuality, the patients and family need a very talented and discriminate, plus a primary care psychiatric doctor or nurse clinician or psychologist to actually give the diagnosis and to plan treatment. Both medications and CBT based and/or DBT-based therapy are required.
6/13/2017 9:32:29 PM

Lizanne Corbit
Succinct, helpful, and informative read. Having accessible information like this is so important because knowledge, and education are two of the biggest tools we have to fight stigma and misunderstanding. These two are tricky to differentiate between, even in the professional field. So allowing the general public to have access to this information is so wonderful.
6/12/2017 11:26:48 PM

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