Mood Disorders

Mood disorders are a broad umbrella term used for conditions in which disturbance of mood is the central feature. Common mood disorders include different types of depressive and bipolar disorders.

While it is normal to experience periods of different moods, mood disorders are characterized by emotional extremes and difficulties in regulating mood.

Mood disorders are found to affect about 20% of the general population at any given time. In the US, an estimated 17% of people are thought to struggle with depression over their lifetime.

Bipolar disorders are rarer. Bipolar I disorder alone has an estimated lifetime prevalence of around 1.5% (American Psychiatric Association, 2022).

Disclaimer: This article is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment.

If you are concerned about your mental health or that of a loved one, please consult a qualified healthcare professional. If you are in crisis or experiencing suicidal thoughts, seek help immediately by calling your local emergency number or a crisis hotline.

Quick Overview of Mood Disorders

Disorder	Hallmark Features
Major Depressive Disorder (MDD)	Persistent sadness, loss of interest, fatigue, feelings of hopelessness
Bipolar I Disorder	Cycles of depression and full mania (extreme highs with risky behavior, racing thoughts, high energy)
Bipolar II Disorder	Cycles of depression and hypomania (less intense highs than mania, but still disruptive)
Cyclothymic Disorder	Chronic mood swings between mild depression and hypomania for 2+ years
Persistent Depressive Disorder (Dysthymia)	Long-term, low-grade depression lasting at least 2 years
Seasonal Affective Disorder (SAD)	Depression tied to seasonal changes (commonly in winter)
Disruptive Mood Dysregulation Disorder (DMDD)	In children, frequent severe temper outbursts and chronic irritability
Premenstrual Dysphoric Disorder (PMDD)	Severe mood changes, irritability, and tension before menstruation

“Affective disorders” vs “mood disorders”:

In clinical literature, these conditions are sometimes called "affective disorders." Today, the term "mood disorders" is far more common and user-friendly. It's the phrasing people typically search for when looking up depression, bipolar disorder, and related conditions.

Examples of Mood Disorders

Mood disorders fall into two broad groups: depressive disorders, where low mood dominates, and bipolar and related disorders, where mood cycles between depression and mania or hypomania. Here is a quick summary before the details below:

• Major depressive disorder: Persistent low mood and loss of interest lasting at least two weeks.
• Bipolar I disorder: At least one full manic episode, usually alongside depressive episodes.
• Bipolar II disorder: Hypomania (a milder high) plus at least one depressive episode.
• Seasonal affective disorder: Depression tied to a particular season, usually winter.
• Cyclothymic disorder: Chronic, milder mood swings that never reach full depression or mania.
• Disruptive mood dysregulation disorder: Frequent, severe temper outbursts in children.
• Persistent depressive disorder: Long-term, lower-grade depression lasting two years or more.
• Premenstrual dysphoric disorder: Significant mood changes tied to the premenstrual phase of the cycle.

Major depressive disorder

Major depressive disorder is characterized by prolonged and persistent periods of extreme sadness.

Sadness is normal after a traumatic event. But if it continues once the event has passed, or there is no clear cause at all, this may be classified as clinical or major depression.

This is a very common mental disorder that is accompanied by a variety of physical, cognitive, and emotional symptoms.

Bipolar I disorder

This disorder is characterized by extreme emotional highs (mania) and extreme emotional lows (depression) that can last for several weeks or longer.

Manic episodes in bipolar I disorder can involve euphoric and/or irritable moods, high energy, being more talkative than usual, and increased self-importance.

Depressive episodes in bipolar I disorder can involve feeling hopeless, lethargic, having difficulty concentrating, feeling worthless, and losing interest in everyday activities.

Bipolar I disorder is sometimes called “manic-depression.”

To be diagnosed, a manic episode must last at least a week, or any length of time if hospitalization is needed, and cause real impairment in daily life (American Psychiatric Association, 2013).

Bipolar I disorder has an estimated lifetime prevalence of around 1.5% (American Psychiatric Association, 2022). It typically first appears in the late teens to 30s, affecting men and women in roughly equal numbers.

Bipolar II disorder

This disorder causes cycles of depression which is similar to those who have bipolar I disorder.

Individuals with bipolar II disorder also experience hypomania, a less severe form of mania.

Hypomanic periods are not as intense or as disruptive as manic episodes, and people are usually able to handle daily tasks despite these episodes.

Hypomania can feel good. A burst of confidence, sociability, and productivity is part of why Bipolar II disorder often goes unrecognized. People rarely seek treatment during a hypomanic episode.

Instead, they tend to seek help during the depressive phase, where the condition can be mistaken for major depressive disorder unless a clinician asks about past hypomanic periods.

Seasonal affective disorder (SAD)

SAD is a type of depression that only occurs during certain seasons. Typically, depressed symptoms start in late autumn or early winter for many people, less commonly starting in spring or summer for others.

The symptoms of SAD resemble those of major depression, although SAD differs in that the individual will usually start to feel better once the season is over.

Cyclothymic disorder

This disorder causes emotional highs and lows believed to be less extreme than in those experiencing bipolar I or II disorder.

Individuals with cyclothymic disorder experience continuous irregular mood swings for extended periods. The mood changes can occur suddenly, at any time, with only short periods of baseline mood.

Disruptive mood dysregulation disorder

This is a newer type of depressive disorder that was added to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).

DMDD is usually diagnosed in children. It involves persistent irritability, anger, and frequent temper outbursts, often without any clear cause.

Persistent depressive disorder

This disorder was previously known as dysthymic disorder, a milder form of major depression.

This type of depressive disorder is long-term, occurring for at least two years for individuals, and the symptoms of depression occasionally lessen during this time.

Premenstrual dysphoric disorder

This is characterized by significant mood changes and irritability during the premenstrual stage of a menstrual cycle.

Individuals with PDD may experience extreme mood swings, hopelessness, anger, anxiety, or tension. Once the individual begins their menstruation, the symptoms usually cease.

Common Symptoms of Mood Disorders

Below are some of the common signs that may be experienced by someone who is experiencing a depressive mood:

• Loss of interest in activities that were once enjoyed
• An increase or decrease in appetite
• Difficulty sleeping or sleeping more than usual
• Being easily upset or crying a lot
• Feeling hopeless and worthless
• Physical symptoms such as headaches or stomach aches
• Withdrawing from social events, friends, or family
• Suicidal ideation

Below are some of the common symptoms of manic or hypomanic episodes:

• Elevated energy: Feeling extremely energized, elated, or wired.
• Rapid speech and movement: Talking faster than usual and moving restlessly.
• Agitation: Irritability or restlessness that feels hard to settle.
• Risk-taking: Impulsive decisions, such as overspending or reckless behavior.
• Overcommitment: Trying to take on many activities or projects at once.
• Racing thoughts: Ideas that move quickly, often with little logical connection.
• Flight of ideas: Thoughts and speech jumping rapidly from topic to topic, often connected only by sound or a loose association rather than logic.
• Grandiosity: An inflated, sometimes unrealistic, sense of one’s own importance, abilities, or destiny.
• Disinhibition: A loosening of normal social restraint, seen as out-of-character spending sprees or sexual behavior.

Unhelpful Thinking Styles

Depressed moods are often fueled by automatic, negative thought patterns known as unhelpful thinking styles. These habits can go unnoticed, yet they intensify emotional distress. Common examples include:

• Mental filter: Focusing only on the negative part of a situation while ignoring positives.
• Catastrophizing: Blowing events out of proportion and expecting the worst.
• Black and white thinking: Seeing things as all good or all bad, with no middle ground.
• Overgeneralization: Assuming one bad event means “it always happens” or “everyone does this.”
• Jumping to conclusions: Assuming you know what others think (mind reading) or predicting the future negatively.
• Personalization: Blaming yourself for things outside your control.
• Shoulding and musting: Pressuring yourself with rigid “I should” or “I must” statements.
• Labeling: Defining yourself or others with global, negative labels (e.g., “I’m stupid”).
• Emotional reasoning: Believing feelings are facts (“I feel anxious, so something bad will happen”).
• Magnification/minimization: Exaggerating others’ strengths while dismissing your own.

Recognizing these patterns is the first step toward challenging and changing them.

How Are Mood Disorders Diagnosed?

According to DSM‑5 criteria, a major depressive episode — and a diagnosis of Major Depressive Disorder (MDD) — requires at least five symptoms, including either:

• Depressed mood most of the day, or
• Loss of interest or pleasure in usual activities
  These symptoms must persist for at least two weeks and cause clinically significant impairment in social, work, or other key areas of life.

Clinicians must also rule out triggers like substance use or medical conditions. The absence of any history of manic or hypomanic episodes is essential to distinguish MDD from bipolar disorders.

Bipolar disorder is often missed or diagnosed late. Because people are more likely to seek treatment while depressed than while manic or hypomanic, bipolar disorder is often mistaken at first for unipolar depression or an anxiety disorder.

This diagnostic delay is well documented in the clinical literature (McIntyre et al., 2020).

Comorbidity is also common. Around 65% of people with bipolar disorder meet criteria for at least one other condition, most often an anxiety disorder or substance-use disorder (Merikangas et al., 2011).

Everyday Sadness vs. Clinical Depression

While it’s normal to feel sad due to life circumstances, sadness typically passes and doesn’t disrupt functioning. In contrast, clinical depression:

• Persists day after day for over two weeks,
• Involves symptoms beyond sadness (like concentration impairment, appetite or sleep changes),
• Substantially affects daily life—work, relationships, and self-care.

Adjustment disorder with depressed mood (sometimes called situational depression) may resolve once a stressor passes—whereas MDD is more persistent and requires professional assessment.

Causes and Risk Factors

While there is no known direct cause for someone to develop a mood disorder, there are some possible contributing factors that may play a part.

Often, the cause of mood disorders is thought to be a combination of biological, genetic, psychological, and environmental factors.

Genetic and Biological Factors

Mood disorders tend to run in families, suggesting a genetic component. For example, having a close relative with a mood disorder increases the likelihood of developing one yourself.

Neurotransmitters such as norepinephrine and serotonin appear to play a key role: depressed individuals often show abnormally low levels, while manic episodes are linked to elevated norepinephrine.

Medications that adjust these neurotransmitters can reduce symptoms, further supporting their role (Price & Drevets, 2010; Victor et al., 2010).

Structural differences in the amygdala and prefrontal cortex have also been observed, with abnormal responses to emotional cues in those with depression and bipolar disorder (Murray et al., 2010).

This is sometimes called the monoamine hypothesis of mood disorders. Too little of these brain chemicals is linked to depressive symptoms, and too much to manic symptoms (Price & Drevets, 2010).

Genetics play a strong role too. Family and twin studies suggest a substantial heritable component to bipolar disorder. Some of this genetic risk is shared with unipolar depression, and some is specific to bipolar disorder (McGuffin et al., 2003).

Still, heritability reflects risk across a population. It is not a guarantee that biology alone explains any one person’s episode.

Environmental and Social Factors

Environmental stressors, such as social isolation, substance misuse, or ongoing life pressures, can increase risk.

In recent years, researchers have noted that heavy technology and social media use is linked with higher rates of depression in adolescents. Heavy users are nearly twice as likely to report low well-being (Twenge, 2020).

Sleep, Routine, and Life-Event Triggers

Life events that disrupt sleep and daily routine can also trigger a mood episode. Jet lag, shift work, or the loss of a relationship that structured someone’s day can destabilize the body’s internal clock enough to set one off (Ehlers et al., 1988).

Positive events can be triggers too.

A promotion, a new relationship, or a creative breakthrough can spark manic rather than depressive symptoms, suggesting some people’s reward systems are especially sensitive to success and opportunity.

Hormonal Factors

Hormonal fluctuations influence mood for some individuals. Disorders like premenstrual dysphoric disorder (PMDD) and postpartum depression highlight the role of reproductive hormones, particularly estrogen and progesterone, in mood regulation.

Gender and Age Differences

Women are diagnosed with depression almost twice as often as men, which may reflect both biological differences (hormones, reproductive events) and social factors such as willingness to seek help.

Adolescents and young adults show the highest risk, with depression rates rising significantly in U.S. teens between 2011–2018 (Twenge, 2020).

Older adults can also be affected, though symptoms are sometimes mistaken for cognitive decline.

Impact of Mood Disorders on Daily Life

Work & School Functioning

Mood disorders can significantly impair concentration, attendance, and performance. Students experiencing impaired mental health are more likely to underperform academically—leading to poor grades or dropping out entirely (Chu et al., 2022).

In the workplace, depression may result in more days absent and reduced productivity, often resulting in job loss or financial strain.

One person shared:

“Too many jobs lost, lots of financial struggles … due to depression/attendance issues.” 

Relationships

Emotional lows, strain, and withdrawal often affect personal relationships. Such dynamics can lead to misunderstandings, isolation, and emotional exhaustion—for both those with mood disorders and their loved ones.

A person living with bipolar disorder reflected:

“I just wanna have a normal stable life the past 4 years have been so incredibly exhausting with all my mood issues.” 

Kay Redfield Jamison is a psychiatrist at Johns Hopkins University School of Medicine who has also lived with bipolar disorder herself. As she explains in her memoir An Unquiet Mind, the manic pole of the illness can feel as seductive as it is destructive.

“When you’re high, it’s tremendous,” she writes. Her account echoes the research: some people are ambivalent about treatment because it also dampens a state they once experienced as valuable, not only as illness (Jamison, 1995).

Physical Health Links

Mood disorders often affect sleep and appetite, causing both insomnia or hypersomnia, and weight changes.

Physical health is also at risk: people with long-term mental health conditions are more likely to develop heart disease, fatigue, headaches, or digestive issues.

Wearable-device research reinforces this link: poor sleep quality measured by wristband trackers correlates with increased depressive symptoms (Zhang et al., 2020). 

Treatment Options for Mood Disorders

Medication

Healthcare providers may recommend medication as part of treatment:

• Antidepressants are commonly prescribed for depressive disorders and work by affecting serotonin or norepinephrine.
• Mood stabilizers such as lithium are often used for bipolar disorder to help regulate mood swings.
• Antipsychotic medications can also be prescribed in certain cases, such as severe mania or treatment-resistant depression.

Psychotherapy

Psychological therapies are frequently used alongside medication. Cognitive behavioral therapy (CBT), for example, has been shown in research to help people identify and challenge unhelpful thought patterns.

For some individuals with mild to moderate symptoms, therapy alone may be effective.

Brain Stimulation Therapies

In treatment-resistant cases, approaches such as electroconvulsive therapy (ECT) or repetitive transcranial magnetic stimulation (rTMS) may be considered by specialists.

These are typically offered when other interventions have not been effective.

Light Therapy

For seasonal affective disorder (SAD), exposure to a light box has been found to reduce depressive symptoms. This is usually recommended as a supplement to other approaches.

Lifestyle and Holistic Approaches

Research suggests that lifestyle factors—such as consistent sleep, exercise, a balanced diet, and stress management practices (e.g., yoga, meditation, or mindfulness)—may help reduce symptoms or support recovery.

Peer support groups can also provide a sense of connection. These are considered complementary strategies, not substitutes for professional care.

Coping and Support

When to Seek Professional Help

Professional help may be appropriate when symptoms:

• Last longer than two weeks,
• Interfere with work, school, or relationships,
• Include suicidal thoughts, or
• Lead to reliance on alcohol or drugs.

Keeping a mood diary can help individuals recognize patterns and share useful information with a clinician.

Supporting a Loved One

Friends and family members can play an important role. Support may include:

• Listening without judgment,
• Encouraging professional evaluation,
• Learning about the condition, and
• Providing practical help (such as attending appointments together).

It’s also important that caregivers look after their own wellbeing, as supporting someone with a mood disorder can be emotionally demanding.

“I didn’t realize how much my depression was affecting work until my partner gently pointed it out. Having someone notice and encourage me to get help made all the difference.”

Do you need mental health help?

USA

Contact the National Suicide Prevention Lifeline for support and assistance from a trained counselor. If you or a loved one are in immediate danger: https://suicidepreventionlifeline.org/

1-800-273-8255

UK

Contact the Samaritans for support and assistance from a trained counselor: https://www.samaritans.org/; email jo@samaritans.org .

Available 24 hours a day, 365 days a year (this number is FREE to call):

116-123

Rethink Mental Illness: rethink.org

0300 5000 927

Related Articles

Depression: How effective are antidepressants? Institute for Quality and Efficiency in Health Care, National Center for Biotechnology Information, U.S. National Library of Medicine. January 12, 2017.

Marken, P. A., & Munro, J. S. (2000). Selecting a selective serotonin reuptake inhibitor: clinically important distinguishing features. Primary care companion to the Journal of clinical psychiatry, 2(6), 205.

Self Help Resources for Bipolar Disorder or Manic Depression

National Institute of Mental Health. Bipolar disorder. Updated January 2020.

Vieta, E., & Sanchez-Moreno, J. (2008). Acute and long-term treatment of mania. Dialogues in clinical neuroscience, 10(2), 165.

References

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596

American Psychiatric Association. (2022). Diagnostic and statistical manual of mental disorders (5th ed., text rev.). https://doi.org/10.1176/appi.books.9780890425787

Chu, T., Liu, X., Takayanagi, S., Matsushita, T., & Kishimoto, H. (2022). Association between mental health and academic performance among university undergraduates: The interacting role of lifestyle behaviors. International Journal of Methods in Psychiatric Research, 32(1), e1938. https://doi.org/10.1002/mpr.1938

Ehlers, C. L., Frank, E., & Kupfer, D. J. (1988). Social zeitgebers and biological rhythms: A unified approach to understanding the etiology of depression. Archives of General Psychiatry, 45(10), 948–952. https://doi.org/10.1001/archpsyc.1988.01800340076012

Jamison, K. R. (1995). An unquiet mind: A memoir of moods and madness. Alfred A. Knopf.

McGuffin, P., Rijsdijk, F., Andrew, M., Sham, P., Katz, R., & Cardno, A. (2003). The heritability of bipolar affective disorder and the genetic relationship to unipolar depression. Archives of General Psychiatry, 60(5), 497–502. https://doi.org/10.1001/archpsyc.60.5.497

McIntyre, R. S., Berk, M., Brietzke, E., Goldstein, B. I., López-Jaramillo, C., Kessing, L. V., Malhi, G. S., Nierenberg, A. A., Rosenblat, J. D., Majeed, A., Vieta, E., Vinberg, M., Young, A. H., & Mansur, R. B. (2020). Bipolar disorders. The Lancet, 396(10265), 1841–1856. https://doi.org/10.1016/S0140-6736(20)31544-0

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Victor, T. A., Furey, M. L., Fromm, S. J., Öhman, A., & Drevets, W. C. (2010). Relationship of emotional processing to masked faces in the amygdala to mood state and treatment in major depressive disorder. Archives of General Psychiatry, 67(11), 1128.

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