Psychology Fanatic

Mood Disorders

| T. Franklin Murphy

Mood Disorders. Psychology Fanatic

Understanding Mood Disorders: Types and Symptoms

In a world where emotions can swing like a pendulum, mood disorders stand as formidable adversaries that intrude upon the sanctity of mental well-being. These psychiatric illnesses, including major depressive disorder and bipolar disorder, are not merely fleeting feelings; they represent profound disruptions in how individuals experience life. Affecting millions globally, these conditions drain energy and extinguish motivation, leaving many feeling ensnared in an unrelenting cycle of despair. With nearly 16% of people experiencing major depression at some point in their lives, it becomes evident that understanding these complex disorders is crucial to fostering compassion and effective interventions.

As we journey into the depths of mood disorders, this article illuminates the intricate tapestry woven from biological factors, environmental influences, and psychological components that shape these experiences. From distinguishing between various types—such as persistent depressive disorder or cyclothymia—to uncovering the neurobiological mechanisms behind them, we aim to demystify what lies beneath the surface. Furthermore, by exploring innovative treatment approaches tailored to individual needs—ranging from psychotherapy to medication—we offer hope for those grappling with these debilitating conditions.

Join us as we unravel the nuances of mood disorders and equip ourselves with knowledge vital for promoting resilience and recovery in our communities.

Introduction: Types and Symptoms of Mood Disorders

Mood disorders encompass a range of psychiatric illnesses that primarily include types of depression and bipolar disorders. These conditions profoundly affect emotions, deplete energy levels, and diminish motivation in those affected. Among the most prevalent mood disorders are major depressive disorder, which impacts nearly 16% of individuals at some point in their lives, and bipolar disorder, with a lifetime prevalence close to 5%. The repercussions of these disorders extend beyond emotional distress; they significantly impair quality of life and are associated with increased mortality rates. In fact, major depressive disorder is recognized as the second leading cause of disability worldwide.

This article delves into the complexities of mood disorders by exploring their types, symptoms, causes, neurobiological underpinnings, and treatment options. It categorizes mood disorders into two primary groups: depressive disorders and bipolar disorders while outlining various subtypes within each category. Furthermore, it discusses how genetic predispositions and psychosocial stressors contribute to these conditions’ development.

By examining neurotransmitter imbalances and structural brain changes associated with mood disturbances, this piece aims to provide comprehensive insights into understanding these mental health issues better while emphasizing the importance of early diagnosis and personalized treatment strategies for effective management.

Types of Mood Disorders

Mood disorders are subdivided into two major categories: depressive disorders and bipolar disorders. Both depressions and bipolar disorders impact the quality of life through dysregulation of emotion, interfering with relationships and motivation. The emotion lability interferes with predictable futures, significantly increasing stress.

Mood disorders often are self feeding systems where symptoms motivate behaviors that increase anxiety and depression, compounding the severity of symptoms rather than healing the wounds.

T. Franklin Murphy wrote, “Anxiousness pushes for immobilization, escaping fears of failure, leaving victims cowering in helplessness to the vicissitudes of life.” He continues, “Depression saps energy, dulling motivation to act. Both diseases can debilitate leading to inactivity, entering life draining practices that are self-perpetuating” (Murphy, 2019). Because of the self-perpetuating nature of the mood disorders, it is essential they get diagnosed and treated early.

Mood disorders are diagnosed as a depressive disorder or a bipolar disorder. Within each of these broad categories, there are several subcategories.

Depressive Disorders

Depressive disorders are a group of mental health conditions characterized by persistent feelings of sadness, hopelessness, and a loss of interest in activities. These disorders can significantly impact a person’s daily life, affecting their mood, thoughts, behavior, and physical health.

Major Depressive Disorder

Major depressive disorder is characterized by a persistent feeling of sadness and emptiness, lasting longer than two weeks. For diagnosis the depressive episode must also include four of the following symptoms:

  • insomnia or hypersomnia
  • increase or decrease of appetite
  • psychomotor agitation or retardation
  • decreased energy
  • decreased concentration
  • suicidal ideation
  • thoughts of worthlessness or guilt

For diagnoses, these symptoms cannot be caused by substance use, general medical conditions, or medication use.

See Major Depressive Disorder for more on this disorder

Persistent Depressive Disorder

​Persistent depressive disorder is a broad category containing four more specific diseases:

1. Dysthymic Disorder

Often dysthymic disorder and persistent depressive disorder are used interchangeably. Dysthymic disorder is a continuous long-term (chronic) form of depression.

Those suffering from dysthymic disorder may disengage from life, losing interest in normal activities, feeling hopeless, and lacking motivation to accomplish simple tasks. Typically, dysthymic disorder is accompanied by low self-esteem and an overall feeling of inadequacy.

In dysthymic disorder these symptoms last for years and may significantly interfere with relationships, school, and work.

See Dysthymic Disorder for more information on this mood disorder

2. Recurrent Major Depression without Recovery Between Episodes

Major depression disorder is debilitating, but when the episodes occur without recovery life can be unlivable. Recurrence of major depressive episodes, as described in the medical community, is the return of the symptoms after at least 2 consecutive months between episodes, during which criteria for a major depressive episode is not met, and there must be 5 out of 9 symptoms of depression (Lye et al., 2020).

3. Major Depressive Episode Superimposing On Dysthymic Disorder (“Double Depression”)

Double depression occurs when a person suffering from dysthymic disorder experiences worsening symptoms, leading to a full episode of major depression (Saling, 2021).

4. Chronic Major Depression

Clinicians diagnose chronic depression when the current major depressive episode has lasted more than two years.

Disruptive Mood Dysregulation Disorder

This diagnostic category is reserved for children between the ages of 6-18 years of age. The main presenting symptom are:

  • anger, and tantrums
  • persistent irritability, or negative mood,
  • and anger that is disproportionate to the situation
  • duration for 12 or more months

These symptoms must go beyond the scope of what is considered normal and age appropriate (Datta et al., 2021).

See Disruptive Mood Dysregulation Disorder for more on this disorder

Premenstrual Dysphoric Disorder

Premenstrual dysphoric disorder is recognized as a distinct disorder in DSM-5. 

Psychological Symptoms:
  • irritability
  • nervousness
  • anger
  • agitation
  • insomnia
  • and depression
Physical components:
  • gastrointestinal symptoms (nausea, bloating, constipation, abdominal cramps)
  • skin issues (acne)
  • neurologic symptoms (headache, dizziness, fainting)
  • ocular symptoms (vision changes and eye infection)

Symptoms must improve within a few days of the onset of menstrual cycles and resolve after menses to be diagnosed with this specific disorder.

At least five physical, affective, and/or behavioral symptoms must be present, and one or more of the following:
In addition one or more of the following bringing the overall total symptoms to at least five:
  • decreased interest
  • decreased concentration
  • change in appetite
  • change in sleep,
  • feelings of being overwhelmed
  • decreased energy
  • Physical symptoms (breast swelling or tenderness, joint or muscle pain, bloating, weight gain) (Datta et al., 2021).

Other Depression Disorders

Drugs, medication, or a general medical condition may cause depression. Physicians may diagnose these episodes of depression and treat them differently.

Bipolar Disorders

Biphasic mood episodes that alter between depression and mania is the main symptom of Bipolar disorder. However, A physician may also diagnose as a depression interrupted by a single episode of mania.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, further breaks down bipolar disorder into four more descriptive subcategories: 

Bipolar I Disorder

Bipolar I is defined as at least one manic episode with elevated moods such as:

  • distractibility
  • insomnia
  • grandiosity
  • flights of ideas
  • goal-directed activities
  • pressured speech
  • and thoughtless risk-taking behavior

For diagnosis symptoms should last at least one week and impair social and occupational functions. Depressive or mixed episodes may also be present (Datta et al., 2021).

Bipolar II Disorder

Bipolar II is when major depressive episodes also have at least one hypomanic episode. Hypomania is an elevated mood and increased energy levels lasting for at least four days. Hypomanic episodes are less severe than manic episodes and do not include psychosis.

The duration of hypomanic episodes varies between patients. In between episodes patients may experience residual symptoms, such as:

​Cyclothymia

Cyclothymia patients don’t meet the threshold for diagnosis of major depression, mania, or hypomania. However, they suffer a low-grade version of mild hypomania and major depression that lasts for at least two years.

See Cyclothymia Disorder for more information

Substance-Induced Bipolar Disorder

When any bipolar diagnoses is induced by substance use, a clinician may diagnose the disorder as substance induced. With this diagnoses, the disorder requires a different form of treatment to combat the substance use or abuse.

See Bipolar Disorder for more on this topic

What Causes Mood Disorders?

Like so many other disorders, typically the cause of mood disorders is a complex mix of genetics and environments that activate susceptibilities. Datta, Suryadevara, and Cheong eloquently wrote, “Highly intricate genetic differences and psychosocial stressors together are typically the determinants for stress responses and the resiliency or susceptibility for depression” (Datta et al., 2021, p. 1,713).

The different mood disorders varying levels of  hereditary associations, with all of them having increased risk when a mood disorder is present in the family. Major depressive order has a significant genetic component. “Genetic studies have revealed a heritability of 37% and a 2.8 times increased risk of developing this illness among first-degree relatives of probands with major depressive disorder” (Rakofsky & Rapaport, 2018).

Long exposure to high stress environments may weaken our resilience, creating greater susceptibility to mood disorders. Gabor Maté​ wrote that, “Excessive stress occurs when the demands made on an organism exceed that organism’s reasonable capacities to fulfill them” (Maté, 2011). In psychology, we refer to this disease model as general adaptation syndrome.

The diathesis stress model provides an accurate description of the possible cause of mood disorders. Murphy wrote that the “diathesis–stress model explores how biological or genetic traits (diathesis) interact with environmental influences (stressors) to produce disorders such as depression, anxiety, or schizophrenia” (Murphy, 2021).

Neurobiology of Mood Disorders

Neurotransmitter imbalances can significantly affect mood, as they are critical chemical messengers in the brain that regulate many aspects of our emotional state. Here’s how imbalances in key neurotransmitters can influence mood:

  • Serotonin: Often referred to as the ‘feel-good’ neurotransmitter, serotonin contributes to feelings of well-being and happiness. Low levels of serotonin are commonly associated with mood disorders such as depression. It’s also involved in regulating sleep, appetite, and digestion. Imbalances can lead to mood swings, sadness, and decreased energy.
  • Dopamine: Known as the “pleasure” neurotransmitter, dopamine is linked to the brain’s reward system. It helps us feel pleasure and satisfaction as part of our reward system. Low dopamine levels can result in a lack of motivation, feelings of apathy, and an inability to experience pleasure, a condition known as anhedonia.
  • Norepinephrine: This neurotransmitter is related to arousal and alertness. It plays a role in the body’s stress response and can affect mood. Imbalances in norepinephrine can lead to anxiety, stress, and depression.
  • GABA (Gamma-Aminobutyric Acid): GABA is an inhibitory neurotransmitter that helps to calm the nervous system. Low levels of GABA can lead to anxiety, chronic stress, and mood disorders.
  • Glutamate: This is an excitatory neurotransmitter that is necessary for learning and memory. However, too much glutamate can lead to overstimulation of the brain, which can contribute to anxiety and stress (Rybakowski, 2013).

When neurotransmitter levels are out of balance, it can disrupt the normal functioning of these systems, leading to mood disorders such as depression and anxiety. Treatments for mood disorders often focus on restoring the balance of neurotransmitters in the brain, either through medication, such as selective serotonin reuptake inhibitors (SSRIs) for serotonin, or through lifestyle changes like exercise and stress management, which can naturally help regulate neurotransmitter levels.

Brain Structure and Function

Brain structure and function have a profound impact on mood, and alterations in these areas are often associated with mood disorders. Here’s how specific brain structures and their functions can affect mood:

  • Prefrontal Cortex (PFC): The PFC is involved in regulating emotions and decision-making. It helps to manage responses to stress and plays a role in mood-related disorders. When the PFC is not functioning properly, it can lead to impulsivity, poor decision-making, and mood instability.
  • Amygdala: This almond-shaped structure is key for processing emotions, especially fear and anger. It helps coordinate responses to environmental stimuli that trigger emotional reactions. Hyperactivity in the amygdala is often linked to anxiety and depression, while hypoactivity can be associated with blunted emotional responses.
  • Hippocampus: The hippocampus is crucial for memory formation and emotional regulation. Stress and mood disorders can lead to a reduction in hippocampal volume, which may contribute to the emotional symptoms seen in mood disorders.
  • Limbic System: This system includes structures like the cingulate gyrus and the parahippocampal gyrus, which impact mood, motivation, and judgment. Dysregulation in the limbic system can lead to mood swings and emotional dysregulation.
  • Gray Matter: Gray matter processes information and is important for movement, emotions, and memory. A reduction in gray matter volume, particularly in the PFC and hippocampus, has been observed in individuals with mood disorders, which may affect cognitive and emotional functioning.
  • White Matter: White matter contains the neural pathways that connect different brain regions. Changes in white matter integrity, such as reduced density or damage to the myelin sheath, can disrupt communication between brain regions, affecting mood regulation (Datta et al., 2021; Pérez-Ramos et al., 2024; Krystal et al., 2024).

Disruptions in specific brain areas can lead to the symptoms observed in mood disorders, such as depression and bipolar disorder.

Other Disorders Contributing to Mood Disorders

Mood disorders are induced by or co-occur with other diseases such as:

  • Multiple Sclerosis
  • Dementia
  • Migraine Headaches
  • Traumatic Brain Injury
  • Parkinson Disease
  • Epilepsy
  • Stroke

Treatments for Mood Disorders?

Professionals treat mild mood disorder symptoms with different forms of therapy. Some people adopt personal practices of meditation and mindfulness to ease symptoms. However, in more serious cases, patients seek treatment from trained medical professionals and medication to supplement therapy and personal practices.

Since mood disorders cover a wide spectrum of symptoms there is no single medication that works universally. Doctors may have to carefully monitor and adjust type and dosage. Physicians can accomplish this only when a patient honestly and routinely reports progress and worsening of symptoms.

Associated Concepts

Theories of the Major Branches of Psychology

  • Cognitive Theories: These focus on how negative thinking patterns and cognitive biases can contribute to mood disorders. For example, Beck’s cognitive theory of depression emphasizes the role of negative schemas, automatic thoughts, and cognitive distortions in the development and maintenance of depression.
  • Biological Theories: These suggest that mood disorders have a strong genetic and biological basis. For instance, relatives of individuals with major depressive disorder or bipolar disorder have a higher risk of developing these conditions. Genetic factors seem to play a stronger role in bipolar disorder than in major depressive disorder.
  • Behavioral Theories: Behavioral concepts relate to how changes in reinforcement and punishment can lead to mood disorders. For instance, the behavioral theory of depression suggests that a reduction in positive reinforcement can lead to depressive symptoms.
  • Social Psychology Theories: These theories look at how mood disorders can be influenced by interpersonal relationships and social environments. For example, the quality of one’s relationships and the ability to form secure attachments are seen as important factors in the development of mood disorders.
  • Psychodynamic Theories: These theories explore how unresolved internal conflicts and past experiences can manifest as mood disorders. They emphasize the unconscious processes and the role of early life experiences in shaping emotional responses.

Treatment and Prevention

  • Treatment Approaches: Various psychological treatments are associated with mood disorders, including cognitive-behavioral therapy (CBT), interpersonal therapy (IPT), and psychodynamic therapy. These approaches aim to address the underlying psychological factors contributing to mood disorders.
  • Prevention and Management: Concepts related to the prevention and management of mood disorders include understanding risk factors, early intervention, and the development of coping strategies to manage stress and emotional challenges.

These concepts provide a framework for understanding the complex nature of mood disorders and guide both research and clinical practice in psychology. 

A Few Words by Psychology Fanatic

In conclusion, mood disorders represent a complex and multifaceted set of psychological conditions that profoundly affect individuals’ lives. From major depressive disorder to bipolar disorder and beyond, the types of mood disorders are as varied as the individuals they impact. The causes, too, are diverse, encompassing genetic predispositions, neurotransmitter imbalances, and psychosocial factors, each intertwining to create a unique pattern of symptoms for every person.

Treatment strategies for mood disorders have evolved significantly, with a growing emphasis on personalized care that considers the biological, psychological, and social dimensions of these illnesses. Pharmacological interventions, psychotherapies, and lifestyle modifications all play critical roles in managing mood disorders, offering hope and improved quality of life to those affected.

As we continue to advance our understanding through research and clinical practice, it is our collective responsibility as mental health professionals to ensure that individuals suffering from mood disorders receive compassionate, comprehensive, and evidence-based care. Let us remain committed to the pursuit of knowledge and the development of innovative treatments that will pave the way for a brighter, more resilient future.

Last Update: January 28, 2026

References:

Datta, S., Suryadevara, U., & Cheong, J. (2021). Mood Disorders. Continuum, 27(6), 1712-1737. DOI: 10.1212/con.0000000000001051
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Krystal, S., Gracia, L., Piguet, C., Henry, C., Alonso, M., Polosan, M., Savatovsky, J., Houenou, J., & Favre, P. (2024). Functional connectivity of the amygdala subnuclei in various mood states of bipolar disorder. Molecular Psychiatry. Nature Publishing Group UK. Advance online publication. DOI: s41380-024-02580-y
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Lye, M., Tey, Y., Tor, Y., Shahabudin, A., Ibrahim, N., Ling, K., Stanslas, J., Loh, S., Rosli, R., Lokman, K., Badamasi, I., Faris-Aldoghachi, A., & Razak, N. (2020). Predictors of recurrence of major depressive disorder. PLoS ONE, 15(3). DOI: 10.1371/journal.pone.0230363
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Maté, Gabor (2008). When the Body Says No. ‎Trade Paper Press; 1st edition. ISBN-10: 0470349476
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Murphy, T. Franklin (2019) Anxiety, Depression, and Inaction. Psychology Fanatic. Published: 1-3-2019; Accessed: 9-26-2022. Website: https://psychologyfanatic.com/anxiety-and-depression/
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Murphy, T. Franklin (2021) Diathesis Stress Model. Psychology Fanatic. Published: 9-7-2021; Accessed: 9-27-2022. Website: https://psychologyfanatic.com/diathesis-stress-model/
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Pérez-Ramos, A., Romero-López-Alberca, C., Hidalgo-Figueroa, M., Berrocoso, E., & Pérez-Revuelta, J. I. (2024). A systematic review of the biomarkers associated with cognition and mood state in bipolar disorder. International Journal of Bipolar Disorders, 12(1). Springer Berlin Heidelberg. DOI: 10.1186/s40345-024-00340-z
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Rakofsky, J., & Rapaport, M. (2018). Mood Disorders. Continuum, 24. Behavioral Neurology and Psychiatry, 804-827. DOI: 10.1212/CON.0000000000000604
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Rybakowski, J. K. (2013). Genetic influences on response to mood stabilizers in bipolar disorder. CNS Drugs, 27(3), 165-173. Springer International Publishing. DOI: 10.1007/s40263-013-0040-7
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Saling, Joseph (2020) Double Depression. WebMD. Published: 8-19-2021; Accessed: 9-27-2022. Website: https://www.webmd.com/depression/double-depression
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