While bipolar and borderline personality disorder have similar symptoms — such as extreme mood swings — that can oft confuse the two, they’re completely different conditions that have their own unique treatments.

Diagnosing either of the disorders is extremely difficult and requires extensive questioning, medical history, and information about the person’s background and symptoms to get to a proper conclusion. It’s especially tricky, since many of these disorders overlap and seem to play off one another.

According to a study published in Psychiatry, a large number of bipolar patients (up to 69 percent) are misdiagnosed initially, and up to one-third remain misdiagnosed for a long time afterward. Many bipolar patients are first diagnosed with depression and prescribed antidepressants — which can actually be dangerous to bipolar patients, since they can induce hypomania and trigger the mania to depression cycle over and over again.

“Missing the diagnosis of bipolar illness is all too common in clinical practice with devastating consequences for patients and families,” said Dr. Prakash Masand, CEO of Global Medical Education.

Bipolar disorder is often confused with borderline personality disorder, so here are the things you should look out for if you or someone you care about is experiencing these muddled symptoms.

Borderline Personality Disorder

People who suffer from borderline personality disorder (BPD) have severe difficulties in regulating their emotions, which often leads to mood swings, impulsiveness, and unstable personal relationships (“I love you!” turns into “I hate you!” quite quickly). In addition to destructive mood swings, BPD patients typically have a very low sense of self-esteem and self-worth, which is manifested in suicidal tendencies like cutting or harming themselves.

They also tend to have a fear of abandonment by family or friends, impulsive behaviors such as reckless spending or driving, and intense moods comprised of anger, depression, or irritability that can last days. The cause of BPD is unknown, but researchers speculate that it’s likely a number of factors, such as genetics, environment, and brain function.

According to the National Alliance on Mental Illness (NAMI), 1.6 percent of Americans have BPD, but it’s likely that number can be as high as 5.9 percent, as there may be undiagnosed or undocumented cases. Interestingly, most of the cases have been among women (75 percent of people diagnosed with BPD are female), but it’s also likely that BPD in males has been mistaken for depression, PTSD, or other mental illnesses. Thus many men may have BPD without a real diagnosis.

Bipolar Disorder

Bipolar disorder shares many of these symptoms — the seemingly reckless behavior, mood swings, and impulsiveness. However, the major defining factor of bipolar disorder involves extreme highs and lows in mood; the former is called euphoria, which involves feelings of excitement, extremely high energy, and grandiosity. Low points are the opposite of mania, characterized by days of deep depression and fatigue, with an inability to focus or be productive. A bipolar person will go from being delusional about having powers, to feeling completely hopeless and empty.

Experts note that one of the main differentiating factors between bipolar and borderline personality disorder is that symptoms of personality disorder are pretty consistent and ongoing, while people with bipolar disorder appear to have “breaks” between their extreme mood swings, in which they experience a mid-range mood where most of the symptoms that are confusing between the two disorders (impulsivity, anger, irritability, extreme emotion) aren’t present.

Secondly, turning to personal relationships can help clarify the difference between the two disorders. According to psychotherapy Russ Federman, writing in Psychology Today, “all personality disorder issues manifest in relation to interpersonal relationships.” In other words, it’s likely that personality disorder symptoms may be triggered by conflict within relationships, while bipolar symptoms usually appear out of nowhere.

“While there is some overlap here with bipolar disorder in the sense that interpersonal stresses may activate a shift in mood phase, bipolar individuals will also tell you that there are times when the onset of their symptoms, whether elevated or depressed, will seem to come out of nowhere,” Federman writes. “There is no obvious trigger or precipitant for their mood destabilization. The only reliable explanation is that there’s been an endogenous shift in their brain activity and their neurochemistry.”

Preventing Misdiagnosis

While there’s currently no biological factor to test for to diagnose these mental disorders, researchers have been working on ways to detect bipolar disorder earlier than before. Family history can be quite telling and is one of the factors a doctor will screen for when diagnosing bipolar patients. One recent study found that glimpsing “subthreshold manic episodes” — symptoms that reflect but don’t manifest bipolar disorder completely — in children of people who have bipolar disorder is a good way to detect it earlier on in people who might be at a higher risk.

The quicker people with bipolar disorder — or borderline personality disorder, or other mental illnesses — can be diagnosed correctly, the quicker effective treatment can be administered. Misdiagnosed patients have a higher risk of worsened symptoms, complications from the disorder or mistreatment, or suicide.

Perhaps most importantly, education about mental illness can help prevent misdiagnoses, as people who are experiencing mood swings or depressive symptoms can be on the lookout for specific features of bipolar disorder (such as the euphoria vs. depression swings) in themselves. A proper diagnosis can save a life, after all.