Signs of Bipolar Disorder in Teens

Bipolar disorder in teenagers shows up as distinct episodes: periods of mania or hypomania (an unusually high, energized or irritable state) and periods of depression, each lasting days to weeks and each clearly different from how your teen normally acts. The single most telling question is not "Is my teen moody?" but "Is this a change from who my teen usually is, and does it last?" This page walks through the signs the National Institute of Mental Health lists for young people, how long a true episode lasts, and how to keep a record that helps a clinician sort it out.

First, if you are worried about safety

The rest of this page is about recognizing patterns over time. For the bigger picture of how bipolar disorder affects young people, including treatment and school, start with our parent’s guide to bipolar disorder in teens and children.

What "episodic" means, and why it matters most

Teenagers have strong feelings, and their moods can turn quickly. That is ordinary. Bipolar disorder is different in one key way: the changes come in episodes. An episode is a run of days in which your teen’s mood, energy, sleep and behavior all shift together, and then, often, shift back.

Clinicians use time thresholds. A summary of the DSM-5-TR criteria in the Merck Manual describes a manic episode as an elevated, expansive or irritable mood plus increased activity or energy lasting at least a week (or any length if a hospital stay is needed). Hypomania uses the same kinds of symptoms for at least four days in a row, without the severe impairment of mania. A major depressive episode lasts at least two weeks. The American Psychiatric Association adds that manic changes are noticeable to friends and family.

That gives parents a practical lens. A teen who storms off after an argument and is fine by dinner is not having an episode. A teen who for ten days barely sleeps, talks over everyone, starts five projects and seems unstoppable, then crashes into weeks of exhaustion, is showing the kind of pattern worth a professional look. If you are unsure which side of the line your teen is on, our page on normal teen mood swings versus bipolar disorder lays the two side by side.

Signs of mania or hypomania in teens

NIMH lists these signs of mania in children and teens. What matters is a cluster of them appearing together, as a change, for days at a time:

• Long periods of intense happiness or silliness that do not fit the situation, such as laughing uncontrollably at a funeral or in a serious class.
• A very short temper or extreme irritability, beyond the teen’s usual baseline.
• Talking fast about many things, jumping from topic to topic, hard to interrupt.
• Trouble sleeping without feeling tired. Not insomnia with exhaustion, but needing little sleep and waking up energized.
• Racing thoughts; a teen may say their mind will not slow down.
• Risky behavior that is out of character, such as reckless driving, spending, or dangerous stunts.
• An inflated sense of ability: believing they can do things that are not realistic, from acing an exam without studying to launching a business overnight.

The sleep sign deserves special attention

Many teens stay up too late with a phone. The difference in mania is that the teen does not seem to need the sleep: three or four hours, night after night, with no fatigue the next day and often more energy than before. Write down bedtimes and wake times if you suspect this.

Grandiosity and sexual behavior

Teens are often confident or dramatic. Grandiosity in mania is a step beyond that: plans or beliefs that are clearly unrealistic and that the teen will not be talked out of. Clinicians who evaluate young people for mania also ask, privately and calmly, about sudden sexual talk or behavior that is out of character, because it can be one form of the risky behavior seen in mania. It has other possible explanations too, including exposure to abuse, so it calls for a careful evaluation rather than assumptions.

Signs of bipolar depression in teens

Depressive episodes are often the first episodes a young person has, and they can look like ordinary depression. NIMH lists these signs in young people:

• Frequent sadness without a clear reason.
• Irritability, anger or hostility (often more noticeable than sadness in teens).
• Frequent complaints of stomachaches or headaches.
• Sleeping much more than usual.
• Feeling hopeless or worthless.
• Eating too much or too little.
• Talking or thinking about death or suicide.

A depressive episode alone does not mean bipolar disorder; most depressed teens do not have it. A past period that sounds like hypomania, or a family history of bipolar disorder, is what makes clinicians look harder. Our page on signs of depression in teens covers depression on its own, and the question of whether an antidepressant could trigger mania is covered in antidepressants and mania risk in teens.

Irritability: the hardest symptom to read

Irritability appears on both NIMH lists, and it is also part of ADHD, anxiety, oppositional behavior and disruptive mood dysregulation disorder (DMDD). On its own it tells you very little. The DSM-5-TR summary reflects this: when the mood in a possible manic episode is only irritable, rather than elevated, four or more other symptoms are needed instead of three.

So the useful questions are about pattern. Is the irritability new, or has it been there for years? Does it come with less sleep, more energy and racing speech? Does it come and go in blocks of days? Long-standing, near-daily irritability with frequent outbursts points more toward DMDD, which is explained in DMDD versus bipolar disorder. Focus problems that have been present since early childhood point more toward ADHD; see ADHD versus bipolar disorder in children and teens.

How common is bipolar disorder in teens?

According to NIMH, based on national survey data collected in 2001 to 2004, an estimated 2.9% of U.S. adolescents aged 13 to 18 had bipolar disorder at some point, and 2.6% had severe impairment. The rate rose with age in that survey: 1.9% at ages 13 to 14, 3.1% at 15 to 16, and 4.3% at 17 to 18. These are older figures using DSM-IV criteria, not current-year numbers, but they match NIMH’s broader point that symptoms most often begin in late adolescence or early adulthood.

Teen bipolar "tests": what parent rating scales can and cannot do

Searches for a "bipolar test for teens" usually lead to questionnaires. Two are used in research and some clinics:

• P-YMRS (parent version of the Young Mania Rating Scale). In one study of youth aged 5 to 17, it separated bipolar disorder from other diagnoses reasonably well (area under the curve above 0.82).
• CMRS-P (Child Mania Rating Scale, parent form), a 21-item parent report that showed strong reliability and distinguished bipolar disorder from ADHD and from children without a diagnosis in its development study.

Both are screening tools. A high score means "look more closely," not "your teen has bipolar disorder," and a low score does not rule it out. The UK’s NICE guideline goes further and advises against using questionnaires in primary care to identify bipolar disorder in young people, recommending diagnosis only after careful monitoring over time by a trained team working with parents. NIMH also notes there is no blood test or brain scan that can diagnose bipolar disorder, although tests may rule out other causes. Our page on screening versus diagnosis explains the difference in more depth.

Keep a parent observation log

NIMH recommends a daily mood chart for young people with bipolar disorder, and the same habit helps before any diagnosis. A few minutes each evening is enough. Track:

1. Sleep: bedtime, wake time, and whether your teen seemed tired the next day.
2. Mood: a simple word or a 1 to 10 rating, plus irritability as its own line.
3. Energy and activity: unusually high, normal, or low.
4. Speech and thinking: faster than usual, normal, or slowed.
5. Notable events: conflicts, risky behavior, school calls, illness, new medicines, alcohol or drugs.
6. Family history notes: relatives with bipolar disorder, depression, or suicide.

Two to four weeks of notes can show whether changes cluster into episodes. Bring the log, along with school reports, to the appointment. Our guide to a teen psychiatric evaluation explains what the visit involves and how parents take part.

At Willow & Stone

Willow & Stone sees patients ages 10 and up, from an office in Arlington, Texas and by telehealth in Texas, New Mexico, Florida, Alaska, Arizona, Colorado and Washington. If your teen’s pattern worries you, bipolar treatment for teens at Willow & Stone describes the evaluation, and bipolar disorder treatment at Willow & Stone covers our care more broadly.

Common Questions

Sources & Further Reading

• NIMH: Bipolar Disorder in Children and Teens (NIH Pub. 23-MH-8081, 2023)
• NIMH: Bipolar Disorder statistics (NCS-A 2001–2004 survey data)
• Merck Manual Professional: Bipolar Disorders (2026)
• American Psychiatric Association: What Are Bipolar Disorders?
• Gracious BL et al. Discriminative validity of a parent version of the Young Mania Rating Scale. J Am Acad Child Adolesc Psychiatry, 2002
• Pavuluri MN et al. Child Mania Rating Scale: development, reliability, and validity. J Am Acad Child Adolesc Psychiatry, 2006
• NICE CG185: Bipolar disorder: assessment and management (last updated 2 Sept 2025)

This article is general education, not a diagnosis or advice for your situation. Do not start, stop, or change a medication without talking to the clinician who prescribes it; stopping a mood stabilizer suddenly can trigger relapse.