Mood Disorders: Types, Symptoms & Treatment

Name: Mood Disorders: Types, Symptoms & Treatment
Creator: Michael Callans
Published: 2026-06-25

Key facts

Mood disorders include depressive disorders and bipolar disorders. Bipolar assessment considers episodes of increased energy and elevated or irritable mood as well as depression. NIMH: bipolar symptoms.
Depression can affect people of any age and background. A major depressive episode involves depressed mood or loss of interest with other symptoms for at least two weeks. NIMH: depression.
Mood disorders involve health, biological, psychological, and environmental factors. Symptoms deserve care, and family history alone cannot determine whether someone will develop a disorder. NIMH: contributing factors.
Psychotherapy and medication are established treatment options. For bipolar disorder, antidepressants alone can trigger mania or rapid cycling, so medication choices require a prescriber familiar with bipolar care. NIMH: treatment.

What are mood disorders?

The term mood disorder covers several diagnoses rather than describing every emotional fluctuation. Recording changes in sleep, activity, concentration, and mood can help a clinician distinguish depression from bipolar episodes and from physical or substance-related causes.

A mood disorder is a mental health condition in which your emotional state is disturbed for a sustained period in a way that interferes with everyday life. Mood naturally shifts in response to events, but with a mood disorder the change is more intense, lasts much longer, and is harder to shake. The two broad patterns are depression, marked by persistent low mood and loss of interest, and mania or hypomania, marked by abnormally elevated or irritable mood and energy. Some conditions involve one pattern, and some involve both.

Mood disorders are common. The National Institute of Mental Health (NIMH) reports that mood disorders affect a substantial share of U.S. adults over the course of a lifetime, and the World Health Organization (WHO) describes depressive disorders as a leading cause of disability globally. If you are living with one, you are in very large company.

Clinicians diagnose mood disorders using the criteria in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association. In broad terms, a diagnosis depends on the type, duration, and intensity of mood symptoms, the presence or absence of manic episodes, and the degree to which symptoms disrupt daily functioning, after a clinician has ruled out a medical cause, medication effect, or substance use. A qualified professional assesses the full symptom history and context before making a diagnosis.

Types of mood disorders

Mood disorders cover several distinct conditions. The most common include:

Major depressive disorder: episodes of persistent low mood, loss of interest, and physical and cognitive changes lasting two weeks or more. See our full guide to depression.
Bipolar disorder: episodes of mania or hypomania and, commonly, depression, with changes in mood, energy, sleep, and judgment. Episodes need not follow an alternating sequence. See our guide to bipolar disorder.
Persistent depressive disorder (dysthymia): a persistent form of depression that typically lasts at least two years in adults. Severity can vary and symptoms may be substantial.
Seasonal affective disorder: depression that follows a seasonal pattern, most often beginning in fall or winter. See seasonal affective disorder.
Postpartum depression: a depressive episode during pregnancy or in the weeks and months after childbirth.
Premenstrual dysphoric disorder: severe mood symptoms before menstruation that improve after it begins. NIMH describes this menstrual-cycle pattern.

How the mood disorder diagnoses below differ in pattern, duration, and key features.
Condition	Core pattern	Typical duration	Key difference
Major depressive disorder	Episodes of persistent low mood and lost interest	Two weeks or longer per episode	No manic or hypomanic episodes
Persistent depressive disorder	Lower-grade but long-lasting depression	Two years or more	Persistent symptoms whose severity can vary; major depressive episodes may also occur
Bipolar I disorder	Full manic episodes, commonly with depressive episodes	Mania lasts a week or more, or requires hospital care	Mania can be severe and disruptive, sometimes with psychosis
Bipolar II disorder	Depression alternating with hypomania	Hypomania lasts at least four days	Elevated periods are milder and never reach full mania

The duration examples above describe adult diagnostic patterns, not a waiting period before seeking help. NIMH depression guidance supports the depression time frames; American Psychiatric Association bipolar guidance explains manic and hypomanic episode criteria. Depression is common in bipolar I but is not required for that diagnosis.

Symptoms

Symptoms depend on whether the mood is low, elevated, or shifting between the two. Depressive symptoms include:

Persistent sadness, emptiness, or hopelessness
Loss of interest or pleasure in usual activities
Changes in sleep, appetite, or weight
Fatigue and low energy
Difficulty concentrating or making decisions
Feelings of worthlessness or guilt
Thoughts of death or suicide

Manic or hypomanic symptoms, which appear in bipolar disorder, include:

Abnormally elevated, expansive, or irritable mood
Increased energy and reduced need for sleep
Racing thoughts and rapid speech
Inflated self-confidence or grandiosity
Impulsive or risky behavior

When these symptoms persist, represent a clear change from your usual self, and interfere with daily life, they may point to a mood disorder. As the Mayo Clinic notes, mood disorders can affect children, teenagers, and adults differently, and symptoms range from mild to severe.

By the numbers

21.4%estimated lifetime prevalence of mood disorders among U.S. adults in the National Comorbidity Survey Replication, conducted from 2001 to 2003NIMH

9.7%estimated past-year prevalence of mood disorders among U.S. adults in the survey conducted from 2001 to 2003NIMH

21.0 millionU.S. adults had at least one major depressive episode in 2021, or 8.3% of all adultsNIMH

322 millionpeople worldwide were estimated to have depression in 2023, according to WHOWorld Health Organization

Causes and risk factors

There is no single cause. Mood disorders usually arise from a combination of factors:

Biology: brain chemistry, hormones, and genetics. Mood disorders, especially bipolar disorder, often run in families.
Life events: trauma, loss, chronic stress, or major change.
Health: chronic illness, chronic pain, thyroid problems, and some medications can contribute.
Substance use: alcohol and drugs can trigger or worsen mood symptoms.

These factors interact rather than act alone. A genetic vulnerability may stay quiet until a stressful period or hormonal shift brings symptoms forward. Mood disorders frequently appear alongside anxiety, and the two can be treated together. Because some physical conditions can mimic a mood disorder, a medical evaluation is part of a thorough assessment.

How mood disorders are treated

“There is effective treatment for mild, moderate and severe depression.”

World Health Organization

Mood disorders are highly treatable. Most people improve substantially with treatment, and a combination of approaches often works best. The right plan depends on the specific diagnosis, its severity, and your preferences, so it is worth discussing the options with a professional.

Psychotherapy

Talk therapy helps you understand and manage the thoughts, behaviors, and relationship patterns tied to your mood. Cognitive behavioral therapy (CBT) helps you recognize and reframe unhelpful thinking. Interpersonal therapy addresses relationship and role changes that can feed low mood. For bipolar disorder, approaches that focus on stabilizing daily routines and sleep, alongside medication, are particularly helpful.

Medication

Tell the prescriber about any past periods of unusually high energy, reduced need for sleep, or impulsive behavior, including times that felt productive. NIMH explains that missed hypomania can lead to a depression-only diagnosis and a medication plan that needs reconsideration.

Medication is often central, especially for moderate to severe conditions. Antidepressants, including selective serotonin reuptake inhibitors (SSRIs), are commonly used for depressive disorders. Mood stabilizers, such as lithium and certain anticonvulsants, are mainstays for bipolar disorder, where antidepressants alone can be problematic. Medication should always be managed by a prescriber. Learn more about antidepressants.

Lifestyle and self-care

Consistent sleep, regular physical activity, social connection, and limiting alcohol all support stability. For bipolar disorder in particular, keeping a steady daily rhythm helps reduce the risk of mood episodes. These measures complement, but do not replace, professional treatment.

Ready to talk to someone? A licensed therapist can help you understand what you are experiencing and build a plan that works for you. Find a Therapist

Does this sound familiar? Take a quiet moment and notice which of these feel familiar from the past few weeks.

I have felt sad, empty, or hopeless for most of the day, more days than not.
I have lost interest in activities I used to enjoy.
My sleep, appetite, or weight has changed noticeably.
I feel tired or low on energy nearly every day.
I have trouble concentrating or making decisions.
I have had stretches of unusually high energy with little need for sleep.
During high-energy periods, I talk faster or act more impulsively than usual.
My mood changes feel out of proportion to what is actually happening in my life.

Take the depression test (PHQ-9 based) or try the bipolar test (MDQ), mania test (ASRM), PMDD test (PSST)

Free, with a plain-language result and a PDF you can bring to a professional. Take the time you need to consider each answer. A screening is not a diagnosis.

Free tools and worksheets

Practical, printable exercises from our free library that people managing mood disorders often find useful. No signup needed.

Mood TrackerA simple daily rating log that makes mood patterns visible over weeks, useful for spotting an episode as it starts. Behavioral Activation PlannerA planner for scheduling small, rewarding activities when depression has drained your motivation, one of the best-tested depression skills. Mood & Activity LogTracks what you do alongside how you feel, so you can see which activities lift your mood and which drag it down. Three Good Things ExerciseA nightly practice of writing down three things that went well, which gently retrains attention toward the positive.

When to seek help

Reach out to a doctor or mental health professional if changes in your mood last more than two weeks, feel out of proportion to events, or interfere with work, relationships, or daily life. Seek help immediately if you have thoughts of harming yourself or notice periods of unusually high energy, little need for sleep, and risky behavior. Mood disorders are treatable, and getting help early makes recovery easier.

Frequently asked questions

What is the difference between a mood disorder and just feeling moody?

Everyone has mood changes that pass as circumstances shift. A mood disorder involves a more sustained or severe change in mood, energy, sleep, and functioning. Episodes can last days, weeks, or longer, depending on the condition. A clinician considers the pattern and its consequences, including changes in judgment or safety, rather than relying on feeling moody alone.

Are mood disorders treatable?

Yes. Mood disorders have effective treatments, including psychotherapy, medication, or a combination tailored to the diagnosis. Many people achieve meaningful improvement and ongoing stability. Bipolar disorder usually needs continuing care even between episodes. Discuss benefits, side effects, sleep routines, and warning signs with your clinician, and avoid changing prescribed medication without their guidance.

Can a mood disorder be inherited?

Genetics play a meaningful role, especially in bipolar disorder. Having a close relative with a mood disorder raises your risk, but it is not a guarantee. Life events and biology interact, so family history is one factor among several. Share relevant family history with the clinician assessing your symptoms.

What is the difference between bipolar I and bipolar II disorder?

Bipolar I involves at least one full manic episode, a period of abnormally elevated mood and energy severe enough to disrupt life or require hospital care. Bipolar II involves hypomania, a milder form of elevated mood, along with episodes of major depression. Both are treatable mood disorders, and a clinician distinguishes them by the intensity and duration of the elevated episodes.

How is a mood disorder diagnosed?

A clinician, usually a psychiatrist, psychologist, or physician, diagnoses a mood disorder through a detailed interview using DSM-5 criteria. They look at the type, duration, and intensity of mood symptoms, whether manic episodes have occurred, and how much daily life is disrupted. A medical evaluation is often included, because thyroid problems, medications, and substance use can produce similar symptoms.

Do mood disorders look different in children and teenagers?

They can. In younger people, depression often shows up as irritability, school problems, or physical complaints rather than obvious sadness, and mood episodes can be harder to separate from typical adolescent changes. Any persistent shift in a child's mood, sleep, energy, or interests that lasts weeks and disrupts school or friendships deserves a professional evaluation.

DepressionThe most common mood disorder
Bipolar DisorderDepression plus mania
Seasonal Affective DisorderSeasonal depression
Depression Statistics 2026Prevalence, treatment, trends
Bipolar Disorder Statistics 2026Prevalence, onset, misdiagnosis

Therapists who specialize in mood disorders

Connect with a licensed therapist on Psychology.com who works with mood disorders.

See all therapists for this →

Finding the right help

When you are ready to take the next step, these guides walk you through finding and starting with the right therapist.

Visit the conditions hub for related guides, including depression or ordinary sadness and seasonal affective disorder. If you use the mood tracker, bring notes on sleep, energy, medications, and daily activities to your appointment. The depression screening can help organize concerns; a clinician still needs to assess possible past mania or hypomania.

References

Written by Michael Callans, MSW

Michael Callans is the founder of Psychology.com. He launched the site in 1998 as one of the earliest mental health resources on the web and has stewarded it and its therapist directory for nearly three decades. He holds a bachelor's degree in psychology from the Illinois Institute of Technology and a Master of Social Work (MSW), and he writes the site's condition guides with a focus on making complex mental health information clear, accurate, and genuinely useful.

Medical disclaimer. This page is for general education and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified health provider with any questions about a medical condition.