Understanding Depression and Its Disorders

Depression

Definition

• Depressive Disorders: Characterized by a sad, empty, or irritable mood, alongside physical and cognitive changes that disrupt daily functioning.

• Differences: Variation in duration, onset, and underlying causes among these disorders.

• Source: (American Psychiatric Association, 2013)

Types of Depressive Disorders

• Major Depressive Disorder (MDD)

  • Most prevalent type of depression.

  • Criteria: At least 5 symptoms lasting 2 weeks or more.

  • Symptoms interfere with daily life (e.g., school, work, relationships, self-care).

• Persistent Depressive Disorder (Dysthymia)

  • Chronic, low-grade depression.

  • Duration: lasts 2+ years in adults and 1+ year in children/teens.

  • Symptoms are milder than MDD but ongoing.

• Premenstrual Dysphoric Disorder (PMDD)

  • Severe form of PMS affecting mood and functioning.

  • Symptoms:

  • Begin 7–10 days before menstruation.

  • Improve shortly after the period starts.

  • Symptoms include intense sadness, anxiety, irritability, mood swings, and anger.

  • Source: (Anxiety and Depression Association of America, n/a)

Signs and Symptoms

• Mood Changes

  • Feelings: sad, tearful, depressed, or irritable.

  • Anhedonia: Losing interest or enjoyment in previously liked activities.

• Social Changes

  • Spending less time with friends.

  • Withdrawing from activities (e.g., after-school or social).

• Physical Changes

  • Changes in appetite or weight.

  • Sleeping patterns: increased or decreased sleep.

  • Persistent tiredness or low energy.

• Thinking and Self-Esteem

  • Feelings of guilt or self-blame.

  • Perception of worthlessness or inadequacy.

  • Impaired concentration or focus.

• School Difficulties

  • Diminished interest in school activities.

  • Declining academic performance.

• Serious Warning Signs

  • Thoughts of suicide or a desire to die.

Depression & Suicide Risk in the US

• Epidemiology: 20% of children and adolescents aged 12–17 have experienced a major depressive episode at some point.

• 1 in 3 adolescents (ages 14–18) report persistent feelings of sadness or hopelessness nearly every day for at least two weeks.

• 18.8% of adolescents have considered attempting suicide seriously.

• Age-Specific Risks: In 2017, suicide was the second leading cause of death for youth ages 10–14 and 15–19.

• Suicide rates: Between 2018 and 2019, approximately 7 out of every 100,000 youth aged 10–19 died by suicide.

• Source: (Casseus & Reichman, 2025)

Prevalence

• General Findings: Depressive disorders are prevalent during adolescence, with an annual prevalence rate of up to 8%.

• By high school completion, nearly 1 in 5 young individuals will have experienced at least one depressive episode.

• Approximately 4% of children aged 3–17 have current depression diagnosis, affecting 3% of males and 6% of females.

• Sources:

  • (Casseus & Reichman, 2025)

  • (American Academy of Children and Adolescent Psychiatry, 2025)

  • (Wiggins et al., 2010)

  • (Centers for Disease Control and Prevention, 2025)

Causes of Depression

• Complexity: No single cause identified for depression among children and adolescents.

• Factors Influencing Development: Combination of genetic and environmental influences.

• Common Risk Factors:

  • Genetics: Family history (having close relatives with depression).

  • Physical health issues or injuries.

  • Stressful life events (e.g., divorce, moving, death of loved ones).

  • Substance use.

  • Bullying or other traumatic experiences.

• Note: Often results from multiple contributory factors.

• Source: (Cleveland Clinic, 2025)

Risk Factors

• Family and Personal History

  • Family members with depression.

  • Personal history of depression, anxiety, ADHD, or conduct issues.

• Life Experiences and Environment

  • Adverse childhood experiences (ACEs)

  • Bullying

  • Family conflicts

  • Grief from loss of loved ones or romantic relationships

  • Friendship or peer relationship complications.

• Biological and Developmental Factors

  • Being female

  • Puberty

  • Health problems (e.g., low birth weight, brain injuries, chronic illnesses like diabetes).

• Behavioral Factors

  • Substance use issues.

• Source: (Cleveland Clinic, 2025)

Treatment

• Research Overview: The Duke Clinical Research Institute conducted the Treatment for Adolescents with Depression Study (TADS).

• Results:

  • Fluoxetine + Cognitive-Behavioral Therapy (CBT): 71.0% positive response.

  • Fluoxetine alone: 60.6% positive response.

  • CBT alone: 43.2% positive response.

  • Placebo: 34.8% positive response.

  • Conclusion: Combining fluoxetine with CBT yields the most significant symptom improvement in adolescents with major depressive disorder.

  • Source: (March et al., 2007)

Additional Treatment Options

• Psychotherapy

  • First-line treatment for mild to moderate depression.

  • Aims to manage negative thoughts, feelings, and life stressors.

  • Effective types include:

  • Cognitive-Behavioral Therapy (CBT): Teaches new thinking and coping mechanisms.

  • Interpersonal Therapy (IPT): Focuses on enhancing interpersonal relationships.

  • Combining therapy and medication is deemed most effective for adolescents.

• Medications

  • Antidepressants: Affect neurotransmitter levels (serotonin, norepinephrine, dopamine).

  • Common types:

  • SSRIs: (e.g., fluoxetine, sertraline) - the most frequently prescribed.

  • SNRIs: (e.g., venlafaxine, duloxetine).

  • Typical onset for medication efficacy: 3–4 weeks.

  • Finding appropriate medication may involve trial and error.

• Electroconvulsive Therapy (ECT)

  • Used for severe or potentially life-threatening depression.

  • Effective alternative when medication fails.

  • Administered under anesthesia in multiple sessions.

• Lifestyle Changes

  • Support mood and recovery.

  • Recommendations:

  • Maintain a healthy diet.

  • Engage in regular physical activity.

  • Ensure exposure to sunlight and outdoor settings.

  • Foster social connections.

  • Source: (Sussex Publishers, n/a)

Major Depressive Disorder (MDD) Characteristics

• Symptoms Required:

  • At least 5 symptoms for a period of at least 2 weeks.

  • Symptoms must signify a change in previous functioning; one of the following symptoms must be present:

  • Depressed Mood OR Loss of Interest/Pleasure (anhedonia).

• Nine Possible Symptoms:

  1. Depressed mood most of the day, nearly every day.

  • (In children/adolescents, this may appear more as irritability.)

  1. Markedly reduced interest or pleasure in most activities.

  2. Significant weight changes (loss or gain of 5% of body weight in one month) or appetite alterations.

  3. Sleep disturbances (either insomnia or excessive sleep, known as hypersomnia).

  4. Psychomotor agitation or retardation observable by others.

  5. Fatigue or loss of energy.

  6. Feelings of worthlessness or excessive/inappropriate guilt.

  7. Trouble concentrating, thinking, or making decisions.

  8. Recurrent thoughts of death or suicidal ideation (with or without a plan or attempt).

Diagnostic Criteria for MDD

• Functional Impairment

  • Symptoms must inflict significant distress or impair social, occupational, or other vital areas of functioning.

• Other Considerations:

  • Symptoms cannot be attributed to substances or medical conditions.

  • Symptoms cannot be better explained by psychotic disorders such as:

  • Schizoaffective disorder

  • Schizophrenia

  • Schizophreniform disorder

  • Delusional disorder

  • History of mania or hypomania must be absent.

  • If mania or hypomania has occurred, consider potential diagnoses of bipolar I or II disorder.

Associated Features of MDD

• Increased Mortality Risk:

  • MDD associates with elevated mortality rates largely due to suicide.

  • Older adults with depression in nursing homes show significant mortality risk within the first year.

• Common Emotional & Behavioral Features:

  • Individuals often exhibit:

  • Tearfulness

  • Irritability

  • Brooding or obsessive rumination

  • Anxiety and excessive worry

  • Phobias

  • Heightened concern regarding physical health

• Children's Depression Presentation:

  • In children, symptoms might display as:

  • Separation anxiety

  • More irritability than sadness.

Somatic Complaints in Depression

• Physical Symptoms Commonly Presented:

  • Headaches

  • Joint pain

  • Abdominal pain

  • Generalized body aches

  • Often lead individuals to seek medical attention prior to psychological care.

Biological & Neurophysiological Correlates

• Despite ongoing research into biological markers for depression, no definitive lab test can currently diagnose MDD.

Development and Course of MDD

• Age of Onset:

  • Can materialize at any age; increases significantly post-puberty.

  • Peak onset in the 20s is prevalent in the U.S.

  • Late-life onset is not uncommon.

• Progression to Other Disorders

  • Some individuals with MDD may later develop:

  • Bipolar disorder (higher risk with adolescent onset, psychotic features, or family history of bipolar disorder)

  • Schizophrenia (more likely to progress from psychotic depression to schizophrenia).

• Age-Related Symptom Differences:

  • Younger individuals may show more hypersomnia and hyperphagia.

  • Older individuals may exhibit melancholic features and more psychomotor disturbances.

  • Earlier onset is generally associated with greater familial incidence and personality disturbances.

  • Important reminder: The overall course does not worsen with aging, and recovery duration remains stable across episodes.

Risk Factors for MDD

• Temperamental Factors:

  • High negative affectivity (neuroticism) significantly increases vulnerability to depression following stress.

• Environmental Factors:

  • Adverse Childhood Experiences (ACEs) are strong predictors.

  • The risk is compounded with repeated exposure to multiple stressors.

  • Women may be more affected by sexual abuse and interpersonal trauma.

• Social Determinants of Mental Health:

  • Associated with a higher risk of depression:

  • Poverty

  • Limited education

  • Experiences of racism

  • Discrimination

  • Ongoing marginalization

• Genetic & Physiological Factors:

  • First-degree relatives exhibit a 2–4x higher risk.

  • Heritability of MDD is approximately 40%.

  • Genetic vulnerabilities are significantly bolstered by neuroticism.

  • Greater risk for early-onset or recurrent depression; specific female reproductive risk periods noted.

  • Higher vulnerability may exist during:

    • Premenstrual phase

    • Postpartum period

    • Perimenopause

Cultural Considerations for MDD

• Cross-Cultural Variation:

  • Notable differences in prevalence rates, illness course, and symptom expression across cultures.

  • However, a syndrome akin to MDD can be recognized globally.

• Symptom Expression Across Cultures:

  • In many cultural contexts, depression can manifest through non-DSM criteria symptoms, including:

  • Social isolation/loneliness

  • Anger

  • Frequent crying

  • Generalized diffuse pain

  • Various physical complaints

  • Clinical Implications: Understanding depressive symptoms necessitates an exploration of cultural meanings of distress, social norms, and cultural interpretations of illness to avoid potential misinterpretations.

Somatization in Cultural Context

• Many cultural groups convey emotional distress via physical symptoms such as:

  • Headaches

  • Fatigue

  • Body pain

  • Psychological symptoms may be minimized or stigmatized, resulting in the underdiagnosis and misattribution of depression.

• Risk of Misdiagnosis

  • There is potential for underdiagnosis or misreporting of depression.

  • Misdiagnosis can occur with schizophrenia spectrum disorders, particularly in ethnic or racial groups experiencing discrimination, which may lead to overdiagnosis of psychotic disorders while mood disorders remain underdiagnosed.

  • Takeaway: There’s a need for culturally sensitive assessment approaches.

Structural & Social Determinants of MDD

• Income Inequality:

  • Countries with higher levels of income inequality see elevated rates of MDD prevalence.

• In the U.S., chronicity of MDD appears higher among

  • African Americans and Caribbean Blacks compared to non-Latinx Whites, likely linked to racism and discrimination, sociostructural hardships, and limited access to high-quality mental health resources.

Comorbidity Associated with Depression

• Substance-Related Disorders

  • Substance use disorder frequently aggravates depressive symptoms, interferes with treatment, and elevates suicide risks.

• Anxiety Disorders

  • MDD frequently coexists with:

  • Panic disorder

  • Generalized anxiety disorder

  • Posttraumatic stress disorder

  • Obsessive-compulsive disorder

• Eating Disorders

  • MDD commonly occurs alongside anorexia nervosa and bulimia nervosa; co-occurrence raises medical risks and suicide rates.

• Personality Disorders

  • Particularly prevalent alongside Borderline Personality Disorder.

Persistent Depressive Disorder (PDD)

• Core Feature:

  • Chronic form of depression lasting at least:

  • 2 years in adults

  • 1 year in children/adolescents

  • The individual's mood remains depressed for most of the day on more days than not; irritability may be predominant in younger individuals.

• Diagnostic Criteria:

  • A. Chronic depressed mood for most of the day for ≥2 years (≥1 year for youth).

  • B. Two or more of the following symptoms:

  • Poor appetite or overeating

  • Insomnia or hypersomnia

  • Low energy or fatigue

  • Low self-esteem

  • Poor concentration or difficulty making decisions

  • Feelings of hopelessness

  • C. No symptom-free interval exceeding 2 months during the 2-year duration, reinforcing the persistent nature of the disorder.

• D. Major Depressive Episodes may also be present, whereby full MDD criteria are met concurrently with PDD, called “double depression.”

  • E. Absence of History of Mania or Hypomania.

  • If such episodes are present, alternative diagnoses of bipolar disorders should be considered.

  • F. Symptoms cannot be attributed to psychotic disorders.

  • G. Rule out potential substance or medical condition causes.

  • H. Symptoms must lead to clinically significant impairment in social, occupational, or other critical areas.

Diagnostic Features: Relation to MDD

• Major depressive episodes may precede PDD or occur during it.

• Continuous full criteria adherence to MDD for 2 years should warrant diagnosis as both Persistent Depressive Disorder and Major Depressive Disorder, clinically referenced as “double depression.”

• Symptom Pattern:

  • At least two of the six associated symptoms during depressed mood periods are required:

  • Poor appetite or overeating

  • Insomnia or hypersomnia

  • Low energy or fatigue

  • Low self-esteem

  • Poor concentration or indecisiveness

  • Feelings of hopelessness

Subjective Experience

• Individuals often characterize their mood with expressions such as:

  • “Sad”

  • “Down in the dumps”

  • “Just how I’ve always been”

  • In early-onset cases, symptoms may seem ego-syntonic, as though they are integrated into the individual’s identity, leading to normalized perceptions that might not be spontaneously reported unless specifically inquired.

Development & Course of PDD

• Onset: Typically occurs in early life (childhood, adolescence, early adulthood), defining it as a chronic course.

• Early Onset (<21 years): Linked to increased personality disorders and substance use disorders.

  • Strong Risk Factor: Development of Borderline Personality Disorder (BPD); potential shared mechanisms for co-occurrence.

• Major depressive episodes can transpire but generally return to chronic baselines, with reduced likelihood of complete remission compared to non-chronic MDD cases.

Risk Factors for PDD

• Temperamental Factors:

  • Poorer future outcomes correlate with high negative affectivity (neuroticism), severity of symptoms, diminished global functions, and concurrent anxiety disorders or conduct disorders.

• Environmental Factors:

  • Childhood adversities inclusive of parental loss or separation raise risk profoundly.

• Genetic & Physiological Factors:

  • There is no substantial distinction between chronic MDD and historical DSM-IV dysthymia; a history of depressive disorders in the family is often noted.

  • Brain regions linked with risk include: prefrontal cortex, anterior cingulate, amygdala, and hippocampus, with potential polysomnographic sleep abnormalities.

Cultural Considerations for PDD

• Cultural norms shape perceived abnormality and influence help-seeking behaviors; some communities might regard chronic depressive symptoms as standard responses to life's hurdles.

Comorbidity with PDD

• PDD shows higher overall psychiatric comorbidity rates than MDD.

• A pronounced overlap occurs with:

  • Anxiety disorders

  • Substance use disorders

  • Personality disorders

• Early-Onset PDD (Before Age 21) is highly associated with DSM-5 Personality Disorders (Clusters B and C) and typically presents greater chronicity, functional impairment, and treatment complexity.

Premenstrual Dysphoric Disorder (PMDD)

• Core Pattern:

  • Occurs in most menstrual cycles, symptoms emerge in the final week before menstruation, improve shortly after initiation, and much are absent in the post-menstrual week.

• Symptom Requirements: At least 5 symptoms must be present, including:

  • Core Mood Symptoms:

  • Marked mood lability, irritability/anger, interpersonal conflict, marked depressed mood, marked anxiety.

  • Additional Symptoms: (% total ≥ 5):

  • Decreased interest in activities

  • Concentration difficulties

  • Lethargy/low energy

  • Appetite changes or cravings

  • Hypersomnia or insomnia

  • Feelings of being overwhelmed

  • Physical symptoms: such as breast tenderness and bloating

Diagnostic Criteria for PMDD

• Functional Impairment: Must cause considerable distress or disruption in work, school, social activities, or interpersonal relationships.

• Rule-outs: Criteria must not overlap with major depressive disorders, panic disorders, persistent depressive disorders, or personality disorders; also, no contributing effects from substances or conditions like hyperthyroidism.

Diagnostic Features of PMDD

• Core Pattern: Consistent premenstrual symptoms of mood lability, irritability, anxiety, and dysphoria, remitting around the menstrual onset.

• Timing is Critical: Symptoms peak near the onset of menstruation and must have a free symptom period during the follicular phase.

Features of PMDD

• Symptom Type: Core symptoms encompassing mood and/or anxiety, frequent behavioral, or somatic complaints. Severity matches major depressive disorder or generalized anxiety disorder, leading to functional impairment, noticeable distress, and occurring specifically premenstrually.

• Diagnostic Confirmation: Requires prospective ratings over at least two symptomatic cycles, where provisional diagnosis may be allowed before formal confirmation.

Development & Course of PMDD

• Symptoms can onset after menarche and resolve post-menopause; recurrence may occur with hormone therapy.

• Chronic but Hormonal Cyclical Course: Symptoms dictate a recurring pattern influenced by hormonal changes.

Risk Factors for PMDD

• Environmental: Factors associated with PMDD include:

  • Stress

  • Personal history of trauma

  • Seasonal shifts

  • Socio-cultural expectations surrounding female roles

• Genetic & Physiological: Heritability estimates for PMS conditions range from 30–80%, though the inheritance nature remains ambiguous.

Cultural Considerations for PMDD

• PMDD recognition spans multiple countries, yet symptom expression frequency, intensity, and perceptions are significantly affected by cultural beliefs surrounding menstruation and gender expectations.

Comorbidity with PMDD

• Prior Disorders: Major depressive disorder frequently cited as the most common prior diagnosis.

• Exacerbating Medical Conditions: Includes migraine, asthma, allergies, seizure disorders; psychiatric conditions such as bipolar disorder, anxiety disorders, bulimia nervosa, and substance use disorders may worsen premenstrually.

• Key Distinction: Symptoms escalating premenstrually without a symptom-free post-menses interval indicate premenstrual exacerbation, not PMDD.

Disruptive Mood Dysregulation Disorder (DMDD)

• Core Features:

  • Severe temper outbursts (minimum three per week) that are disproportionate to situations, combined with a persistent irritable mood observable by others, occurring for at least 12 months without symptom-free periods extending 3 consecutive months.

DMDD Settings & Age Requirements

• Symptoms present in two or more settings (e.g. home, school, among peers).

• Diagnosis guidelines restrict making diagnoses:

  • Before age 6 or after age 18, onset must have occurred before the age of 10.

• Rule-Outs: Absence of manic/hypomanic episodes must be confirmed, otherwise consider bipolar disorder, ensuring symptoms are not exclusive to MDD or dictated by PTSD, Autism Spectrum Disorder, or separation anxiety.

DMDD Hierarchical Rules

• Cannot coexist with oppositional defiant disorder or intermittent explosive disorder; may coexist with MDD, ADHD, and conduct disorder. If both DMDD and ODD present, diagnose solely with DMDD.

• Substance & Medical Checking: Ensure symptoms are neither substance-induced nor linked to any medical/neurological conditions.

Core Features of DMDD

• Defined by non-episodic irritability, described chiefly through:

  • Frequent Temper Outbursts: verbal or aggressive behaviors occurring ≥3 times per week, disproportionate to triggering frustrations, and developmentally inappropriate.

  • Persistent Irritable Mood: Sustained irritable or angry mood between outbursts, observable by others, often marking the child’s baseline mood.

Development and Course of DMDD

• Age Parameters: Onset occurs before age 10, with designated diagnosis parameters restricting to ages 6–18 and prohibiting this for developmental ages below 6.

• Course Over Time: About 50% retain full criteria status a year later, with continued indications of impairing irritability even post-criteria fulfillment; risk for transitioning to MDD or anxiety disorders noted, with low likelihood for conversion to bipolar disorder.

Risk Factors for DMDD

• Temperamental Risks: Chronic irritability often correlating with earlier oppositional defiant disorder diagnoses.

• Common Comorbidities: Includes ADHD and anxiety disorders alongside DMDD.

• Environmental Risks: Factors like psychological trauma, parental psychiatric illness, family disruptions, or low educational achievements raise vulnerability.

• Genetic & Physiological: Family history involving depression serves as a substantial risk factor influencing subsequent conditions.

Cultural Considerations for DMDD

• Limited cross-cultural data exists, but sociocultural stresses significantly affect the disorder’s presentation.

Comorbidity with DMDD

• Strongest Overlap: With oppositional defiant disorder as the most frequently occurring comorbid condition alongside behavior and mood disorders, including anxiety disorders, further necessitating the evaluation of symptom responses relative to stressors.

Resources for Youth

• Apps:

  • mADAP: Video-based mobile app providing information on depression aligned with Johns Hopkins University's ADAP.

  • CBT Tools for Youth: Offers insight into depression with templates for CBT skills.

  • Mood Tools: Similar utility to above, coupled with implementing coping and safety plans.

  • CBT Diary: Walkthrough of CBT practices (free with ads).

• Websites:

  • National Alliance of the Mentally Ill (NAMI)

  • Depression and Bipolar Support Alliance

• Source: (American Academy of Children and Adolescent Psychiatry, 2025)

References

• Casseus, M. and Reichman, N.E. (2025). Anxiety, Depression, and Behavioural Problems Among US Children and Adolescents, 2016–2022. Inf Child Dev, 34: e70008. https://doi.org/10.1002/icd.70008

• Depression Resource Center.(2025). American Academy of Children and Adolescent Psychiatry. https://www.aacap.org/AACAP/FamiliesandYouth/ResourceCenters/DepressionResourceCenter/DepressionResource_Center.aspx

• Diagnostic and statistical manual of mental disorders (5th ed). (2013). American Psychiatric Association.

• Is your child depressed?. Cleveland Clinic. (2025, July 11). https://my.clevelandclinic.org/health/diseases/14938-depression-in-children

• March, J. S., Silva, S., Petrycki, S., Curry, J., Wells, K., Fairbank, J., Burns, B., Domino, M., McNulty, S., Vitiello, B., & Severe, J. (2007). The treatment for adolescents with Depression study (TADS). Archives of General Psychiatry, 64(10), 1132. https://doi.org/10.1001/archpsyc.64.10.1132

• Resources for youth. (2025). American Academy of Children and Adolescent Psychiatry. https://www.aacap.org/AACAP/FamiliesYouth/ResourceCenters/DepressionResourceCenter/ResourcesForYouth/AACAP/FamiliesandYouth/ResourceCenters/DepressionResourceCenter/ResourcesforYouthDepression.aspx?hkey=35bc12f7-63a0-436f-b034-1d633892926f+%E2%80%8B

• Sussex Publishers. (n.d.). Depressive disorders. Psychology Today. https://www.psychologytoday.com/us/conditions/depressive-disorders?msockid=1e169ecf720265453ffd886073af647a

• What is Depression?. Anxiety and depression association of America. (n.d.). https://adaa.org/

• Wiggins, A., Oakley, M. B., Bearsley-Smith, C., & Villanueva, E. (2010). Depressive disorders among adolescents managed in a child and Adolescent Mental Health Service. Australasian Psychiatry, 18(2), 134–141. https://doi.org/10.3109/10398560903296657