Mood instability is a common symptom of bipolar disorder (BD). Many people experience rapid changes in mood — sometimes known as mood swings — from time to time, but that doesn’t necessarily indicate BD.

But extreme mood changes may be mood episodes associated with BD. A mental health evaluation and diagnosis can help you determine whether your highs and lows are typical or whether they need to be managed with therapy and medication.

Here’s a deeper look at when mood changes might be BD and what else they could be signaling.

The ups and downs in BD tend to last longer than regular changes in mood. If you have BD, your extreme mood changes will likely interfere with your ability to function in daily life.

Mood changes can go in any direction, whether it’s from happy to sad, calm to angry, or friendly to irritable. Mood changes that are problematic may involve a rapid shift from one intense emotion to another. You may have trouble regulating these changes or managing your behavior and how you react to the changes.

A 2015 study found that mood instability is quite common. Mood shifts can be a symptom of mental health conditions.

In people with depression, anxiety disorder, post-traumatic stress disorder, and obsessive-compulsive disorder, 40% to 60% have mood changes.

Bipolar disorder is one of several mood disorders that can cause mood changes. Others include depression, seasonal affective disorder, and self-harm.

For people living with BD, moods are rarely balanced. Instead of feeling even-keeled, you may feel unbalanced, experiencing manic periods followed by depressive ones.

There are three types of BD: bipolar I, bipolar II, and cyclothymia. People with bipolar II disorder or cyclothymia may have “hypomanic” episodes that include elevated moods and energy, but these episodes tend to be less intense than those associated with bipolar I disorder.

What we think of as mood changes are most like cyclothymia because depressive and manic symptoms are milder, and moods can change more rapidly than with other bipolar diagnoses.

Mood shifts are a symptom of many other physical conditions and mental health conditions, including:

  • anxiety
  • stress
  • ADHD
  • insomnia
  • dementia and other neurological conditions
  • substance use disorder
  • low blood sugar
  • thyroid issues
  • heart problems
  • hormone changes that occur with periods, pregnancy, perimenopause, and menopause

Symptoms of BD usually start in late adolescence or early adulthood. Mood shifts experienced beyond these stages may be an indicator that you’re dealing with something other than BD — including certain stressful life changes.

A 2022 survey from UVA Health found that over 60% of female respondents experienced premenstrual mood shifts and anxiety, a figure so significant that it’s a “key public health issue globally.”

Manic and depressive moods are a symptom of each of the three types of BD:

  • Bipolar I: In this type, manic episodes last at least 7 days or are severe enough to require hospitalization. Depressed episodes last at least 2 weeks. It’s also possible to experience manic and depressive symptoms in the same episode. “Rapid cycling” is a feature of BD that means you have 4 or more manic or depressive episodes in one year.
  • Bipolar II: In this type, depressive episodes and hypomanic episodes are less severe than mania with bipolar I.
  • Cyclothymic disorder: In this type, hypomanic and depressive symptoms are less intense and don’t last as long as other bipolar diagnoses.

Symptoms of a manic episode include:

  • feeling high, euphoric, or happy
  • feeling irritable
  • feeling more energetic and active than usual
  • talking fast about different ideas, having racing thoughts
  • being unable to sleep or not getting tired even when you’re very active
  • feeling like you’re more important, powerful, or talented than usual
  • over-engaging in pleasurable activities like eating, drinking, shopping, and sex

During depressive episodes, people experience these symptoms:

  • feeling sad or anxious
  • feeling hopeless or worthless
  • having difficulty concentrating or making decisions
  • being forgetful
  • talking slowly
  • feeling restless
  • feeling like you’re “slower” than normal
  • having difficulty sleeping or sleeping too much
  • having less interest in activities
  • having trouble doing even simple daily tasks
  • having suicidal thoughts

If you’re feeling the symptoms of bipolar disorder described above, talk with a doctor. BD is a long-term condition that requires consistent treatment.

Even if you think your mood shifts aren’t caused by BD, consider talk with someone about it if they interfere with your daily life. You can also check in with your primary doctor or a counselor.

If you have other symptoms that could potentially point to one of the conditions listed above or have been previously diagnosed with another condition that could be related, you should discuss them with your doctor.

In addition, mood shifts can be a side effect of medications. If you have started a new medication recently, let your prescriber know if you believe the medication is having a significant effect on your mood.

Mood changes are a common symptom of many physical conditions and mental health conditions, including bipolar disorder. Depending on the frequency and severity of your mood changes, BD might be the cause.

Talk with a doctor if your mood changes are severe enough to affect your daily activities and relationships, or if you have other symptoms of bipolar disorder or another condition.