Diagnostic Criteria and Core Features of Major Depressive Disorder

Diagnostic Requirements

• Major depressive disorder is diagnosed when at least five of nine specified symptoms are present during the same 2‑week period, and one of those symptoms must be either depressed mood or markedly diminished interest/pleasure (anhedonia)【1】【2】.

Core Symptom Domains

Mood and Interest

• Depressed mood (or, in children and adolescents, an irritable mood) must be present most of the day, nearly every day【1】【2】.
• Markedly diminished interest or pleasure in almost all activities must be present most of the day, nearly every day【1】【2】.

Neurovegetative Symptoms

• Sleep disturbance (insomnia or hypersomnia) occurs nearly every day【1】【2】【3】.
• Appetite or weight changes (significant weight loss/gain or increased/decreased appetite) occur nearly every day; in children and adolescents this includes failure to achieve expected weight gain【1】【2】.
• Energy depletion (fatigue) is experienced nearly every day【1】【2】【3】.

Psychomotor Symptoms

• Psychomotor agitation or retardation observable by others is present nearly every day【1】【2】.

Cognitive and Affective Symptoms

• Diminished ability to think, concentrate, or make decisions (indecisiveness) occurs nearly every day【1】【2】.
• Feelings of worthlessness or excessive/inappropriate guilt occur nearly every day【1】【2】.

Suicidal Ideation

• Recurrent thoughts of death, suicidal ideation without a specific plan, suicide attempts, or a specific plan to commit suicide are present nearly every day【1】【2】.

Exclusion Criteria

• Diagnosis is not made when the symptom pattern meets criteria for a mixed episode (simultaneous manic and depressive features)【1】【2】.
• Diagnosis is not made when symptoms are attributable to the direct physiological effects of a substance (e.g., drug of abuse, medication) or a general medical condition (e.g., hypothyroidism)【1】【2】.
• Symptoms that are better explained by bereavement are excluded unless they persist longer than 2 months or are accompanied by marked functional impairment, morbid preoccupation with worthlessness, suicidal ideation, psychotic features, or psychomotor retardation【1】【2】.

Functional Impairment Requirement

• The symptoms must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning【1】【2】【4】.
• This requirement distinguishes major depressive disorder from subsyndromal or minor depression, which involves fewer symptoms and less functional impact【5】【3】.

Adolescent‑Specific Presentations

• In children and adolescents, irritable or cranky mood may replace classic depressed mood【1】【6】.
• Additional adolescent indicators include:
  
  • Preoccupation with song lyrics suggesting life is meaningless【6】.
  • Loss of interest in sports, video games, or peer activities【6】.
  • Excessive late‑night television viewing or refusal to wake for school【6】.
  • Talk of, or attempts to, run away from home【6】.
  • Persistent boredom【6】.
  • Oppositional or negative behavior【6】.
  • Poor school performance or frequent absences【6】.

Duration and Temporal Pattern

• Symptoms must be present during the same 2‑week period and represent a change from previous functioning【1】【2】【3】【4】.

All statements are supported by the cited references.

Guidelines for Differentiating Grief from Major Depressive Disorder

Diagnostic Criteria & Temporal Thresholds

• In grief, self‑esteem is generally preserved, whereas major depressive disorder (MDD) is characterized by pervasive feelings of worthlessness. 7
• MDD often presents with prominent neurovegetative symptoms (e.g., sleep disturbance, appetite change, fatigue, psychomotor changes). 7
• Bereavement‑related symptoms meet criteria for MDD when any of the following are present:
• Core MDD diagnosis requires ≥ 5 of 9 symptoms during the same 2‑week period, with at least one being depressed mood or anhedonia; depressed mood is a mandatory symptom. 7
• Temporal algorithm:

Screening Tools

• The PHQ‑9 is recommended as the initial screening instrument for depressive symptoms in bereaved individuals. A total score ≥ 10 indicates moderate depression and warrants further evaluation. 8
• A positive response to PHQ‑9 item 9 (thoughts of death or self‑harm) signals suicidal ideation and requires immediate clinical assessment. 9

Treatment Recommendations for MDD (including bereavement‑related)

• First‑line management includes second‑generation antidepressants or evidence‑based psychotherapies such as cognitive‑behavioral therapy or interpersonal psychotherapy. 10
• Clinical response should be assessed within 1–2 weeks after initiating treatment. 10
• If an adequate response is not observed, treatment modification is advised by 6–8 weeks. 10
• After achieving remission, continue therapy for 4–9 months for a first episode; longer durations are recommended for recurrent episodes. 10
• Ongoing monitoring should begin within 1–2 weeks of any intervention to evaluate efficacy and adverse effects. 10

Age‑Specific Considerations

• Adults 18–29 years: Prioritize psychotherapy over SSRIs because SSRIs are associated with a higher risk of suicidal behavior in this age group. 11
• Adults ≥ 65 years: Favor psychotherapy or non‑SSRI pharmacologic options due to an increased risk of upper gastrointestinal bleeding with SSRIs. 11

Clinical Pitfalls & Safeguards

• Do not assume that all post‑loss depressive symptoms constitute “just grief”; apply full diagnostic criteria to identify treatable MDD after the appropriate timeframe. 7
• Avoid pathologizing normal grief by respecting the 2‑month threshold and requiring additional severe features (worthlessness, suicidal ideation, psychosis, psychomotor retardation) before diagnosing MDD earlier. 7
• Always assess for suicidal ideation in bereaved individuals, even when full MDD criteria are not met. 9

Diagnostic Criteria and Severity Grading for Major Depressive Disorder

Diagnostic Requirements

• Major Depressive Disorder (MDD) is diagnosed when ≥5 of the 9 DSM‑5 symptoms are present within the same 2‑week period, and at least one of these symptoms is either depressed mood (or irritable mood in children/adolescents) or anhedonia【12】【13】.
• The symptom count must represent a change from the individual’s previous level of functioning【12】【13】.

Core Symptom List (DSM‑5)

• Depressed mood (or irritable mood in children/adolescents) occurring most of the day, nearly every day【12】【13】.
• Markedly diminished interest or pleasure (anhedonia) in almost all activities, most of the day, nearly every day【12】【13】.
• Significant weight change (≥5 % body weight in a month) or appetite change, occurring nearly every day【12】【13】.
• Insomnia or hypersomnia nearly every day【12】【13】.
• Psychomotor agitation or retardation observable by others, nearly every day【12】【13】.
• Fatigue or loss of energy nearly every day【12】【13】.
• Feelings of worthlessness or excessive guilt nearly every day【12】【13】.
• Diminished ability to think, concentrate, or indecisiveness nearly every day【12】【13】.
• Recurrent thoughts of death, suicidal ideation, plan, or attempt【12】【13】.

Functional Impairment

• The symptom constellation must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning【12】【13】.

Severity Grading

• Mild MDD – 5–6 symptoms of mild intensity with minimal functional impairment【12】【13】.
• Moderate MDD – Symptom count, intensity, and functional impairment fall between mild and severe levels【12】【13】.
• Severe MDD – Any of the following qualifies:
  
  • All 9 symptoms present, or
  • Severe functional impairment (e.g., inability to leave home)【12】, or
  • Presence of a specific suicide plan, clear intent, or recent attempt【13】, or
  • Psychotic symptoms【12】【13】, or
  • Marked psychomotor retardation【12】【13】.

Episode Duration and Course

• Symptoms must be present continuously for at least 2 weeks【12】【13】.
• In practice, depressive episodes typically last considerably longer than the minimum 2 weeks and may be followed by inter‑episode remissions【12】【13】.

Special Populations – Adolescents

• In adolescents, irritable or “cranky” mood can substitute for depressed mood as a required symptom【12】【13】.

Biomarker‑Symptom Associations

• Elevated C‑reactive protein (CRP) is specifically linked to fatigue and atypical appetite changes, independent of overall depression severity【14】.

Evidence level for all above statements is based on the *DSM‑5 consensus guidelines** (expert consensus/clinical guideline).