Bipolar Disorder vs. Depression: What’s the Difference?
These mood disorders are similar, but a key symptom sets them apart.

Bipolar disorder might be known for causing two “extremes” of the mood spectrum—mania and depression—yet recognizing symptoms of bipolar disorder can still be challenging. Manic episodes often occur infrequently, and some types of manic symptoms (like impulsive spending) may fly under the radar to friends and family. In fact, to an outsider, someone’s bipolar disorder may seem indistinguishable from depression.
One possible reason for the confusion? Americans are more familiar with what depression looks like. Approximately 6.7 percent of adults in the United States have had at least one major depressive episode, while only 2.8 percent of U.S. adults have had bipolar disorder in the past year, according to the National Institute of Mental Health (NIMH).
“Bipolar disorder is a mental illness that involves both having had an experience of a manic episode, as well as experiencing depressive episodes,” says Susan Samuels, MD, psychiatrist at New York-Presbyterian Hospital, Weill Cornell Medicine. Learn more about the types of bipolar disorder here.
How Bipolar Differs from Depression
Since bipolar disorder and depression both include depressive symptoms, the difference really boils down to mania. It only takes one manic episode to classify someone as having bipolar disorder instead of depression.
“The difference between bipolar disorder and depression is [the] presence of a manic episode,” says Ben Michaelis, PhD, a psychologist in New York City. “Once you have a manic episode, [the diagnosis] moves immediately from a depressive disorder to a bipolar disorder.”
Manic episodes can fall on a spectrum of severity. What most people consider a manic episode is actually on the severe end of the spectrum. Here are symptoms of a severe manic episode, according to Dr. Samuels:
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Extreme distractibility
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Impulsivity
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Speaking fast
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Not needing sleep
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Feeling invincible and on top of the world
But someone with bipolar depression may also experience hypomanic episodes, which are much less severe and may be less obvious to outsiders—or even to the person experiencing them. Being easily agitated, having trouble with budgeting, racing thoughts, or poor sleep habits are all signs of a hypomanic episode.
Someone with depression, on the other hand, doesn’t flip to mania. “Depression is unipolar depression, meaning you only go to the one pole of low mood,” says Gail Saltz, MD, psychiatrist at New York-Presbyterian Hospital, Weill Cornell Medicine. Learn more about the symptoms of depression here.
Why Knowing the Difference Really Matters
Despite the similarities in the two mood disorders, recognizing bipolar disorder is critical and even lifesaving. Severe manic episodes can be destructive and dangerous, and dealing with them can be exhausting.
Among those with bipolar disorder, more than 80 percent experience “serious impairment” that affects their personal and professional lives, according to the NIMH, which is the highest among all mood disorders. This means treating bipolar disorder demands careful methods and targeted medication.
“Medications that you choose that might treat the depressive episode can cause one to move into a hypomanic state if you are not aware that you have bipolar disorder,” explains Dr. Saltz. Instead of antidepressants, doctors may prescribe mood stabilizers or antipsychotic drugs for someone with bipolar disorder.
If you have depression or bipolar disorder and are experiencing thoughts of self-harm or suicide, call 911, go to the emergency room, or call the National Suicide Prevention Lifeline: 1-800-273-8255.
Dr. Samuels is an assistant professor of clinical psychiatry and clinical pediatrics at Weill Cornell Medicine and an assistant attending psychiatrist at NewYork-Presbyterian Hospital.
Ben MichaelisDr. Michaelis is a clinical and media psychologist in New York City.
Gail SaltzDr. Saltz is a clinical associate professor of psychiatry at the NewYork-Presbyterian Hospital and Weill Cornell Medicine and a psychoanalyst with the New York Psychoanalytic Institute.
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Bipolar disorder is a mental illness that
involves both having had an experience
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of a manic episode, as well as
experiencing depressive episodes.
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[MUSIC]
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So the difference between
bipolar disorder and
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depression is by that
presence of a manic episode.
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Once you have a manic episode,
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it moves immediately from a depressive
disorder to a bipolar disorder.
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Because the assumption is that you
have had both of those things.
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And someone that has a manic
episode is very likely to also have
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a depressive episode.
So
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a severe manic episode would look like
somebody with extreme distractibility,
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impulsivity, speaking excessively fast,
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not needing to sleep,
feeling like they're on top of the world.
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And really,
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all of these symptoms to the most
extreme that you could possibly imagine.
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With a hypomanic episode, they'll have
some of these very same symptoms, but
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they won't be quite as severe.
Depression is unipolar depression,
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meaning you only go to
the one pole of low mood.
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You have serious sadness, hopeless,
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helpless, for
weeks on end episodes of depression.
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And it is different from having this
other pole where you feel expansive or
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high or irritated or agitated.
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And you need to have episodes of
that intermittently, at least,
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or once or twice,
in order to call it bipolar disorder.
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And why is that important?
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It is important because medications
that you choose that might treat
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the depressive episode can cause
one to move into a hypomanic state
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if you are not aware that
you have bipolar disorder.
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So knowing that is important
in terms of treatment.
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Bipolar disorder can be very,
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very serious.
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The reason for that is during a manic
episode, or even during a depressive
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episode, if it's particularly severe,
there can be negative and
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perhaps risky behaviors that can lead
to very, very serious consequences.
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If you ever feel like you might want
to harm yourself or somebody else,
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please call 911 immediately or
proceed to your nearest emergency room.
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It's also good to have on hand
the National Suicide Prevention Lifeline,
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which is 1-800-273-8255.
Altamura AC, Lietti L, Dobrea C, Benatti B, Arici C, Dell-Osso B. Mood stabilizers for patients with bipolar disorder: the state of the art. Expert Rev Neurother. 2011 Jan;11(1):85-99.
Bipolar disorder. Bethesda, MD: National Institute of Mental Health. (Accessed on April 15. 2021 at https://www.nimh.nih.gov/health/topics/bipolar-disorder/index.shtml.)
Prevalence of bipolar disorder among adults. Bethesda, MD: National Institute of Mental Health. (Accessed on April 15. 2021 at https://www.nimh.nih.gov/health/statistics/bipolar-disorder.shtml.)