What are the DSM‑5 diagnostic criteria for major depressive disorder?

DSM-5 Diagnostic Criteria for Major Depressive Disorder

A diagnosis of major depressive disorder requires at least 5 out of 9 specific symptoms present during the same 2-week period, with at least one symptom being either depressed mood or loss of interest/pleasure (anhedonia), and these symptoms must cause clinically significant distress or functional impairment. 1, 2, 3

Core Symptom Requirements

The 9 symptoms that constitute the diagnostic criteria include: 1, 2, 4

• Depressed mood most of the day, nearly every day (in children and adolescents, this can manifest as irritable mood) 1
• Markedly diminished interest or pleasure in all or nearly all activities most of the day, nearly every day (anhedonia) 1
• Significant weight change (more than 5% of body weight in a month) or appetite disturbance; in children, failure to make expected weight gains 1
• Sleep disturbance: insomnia or hypersomnia nearly every day 1
• Psychomotor changes: agitation or retardation nearly every day, observable by others 1
• Fatigue or loss of energy nearly every day 1
• Feelings of worthlessness or excessive/inappropriate guilt (which may be delusional) nearly every day 1
• Diminished ability to think or concentrate, or indecisiveness, nearly every day 1
• Recurrent thoughts of death (not just fear of dying), recurrent suicidal ideation without a specific plan, suicide attempt, or a specific plan to commit suicide 1

Essential Exclusion Criteria

After meeting the symptom threshold, several exclusionary criteria must be evaluated: 1, 2, 5

• The symptoms must not meet criteria for a mixed episode (simultaneous manic and depressive symptoms) 1
• Functional impairment must be present: symptoms must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning 1, 2
• The symptoms cannot be due to direct physiologic effects of a substance (drug of abuse or medication) or a general medical condition (e.g., hypothyroidism) 1, 2
• The symptoms are not better accounted for by bereavement, though this requires careful assessment (see below) 1
• Psychotic symptoms occurring outside the depressive episode exclude the diagnosis 5

Research indicates these exclusion criteria have only modest impact in clinical practice, affecting approximately 3% of patients who meet symptom criteria. 5

Special Considerations for Bereavement

Depression during bereavement should be diagnosed with caution, requiring persistence of symptoms for at least one month and the presence of features atypical for normal grief. 2, 3

Atypical features that suggest MDD rather than normal grief include: 3

• Extreme beliefs of worthlessness or guilt unrelated to the deceased
• Psychotic symptoms
• Suicidal ideation
• Psychomotor retardation

The ICD-11 maintains a higher diagnostic threshold during bereavement (consistent with DSM-IV), while DSM-5 eliminated the special bereavement exclusion—this represents an area of ongoing controversy. 6

Severity Classification

Depression severity is classified based on three dimensions: symptom count, symptom intensity, and degree of functional impairment. 2, 7

• Mild depression: 5-6 symptoms with mild intensity and minimal functional impairment; patients generally maintain daily activities with some difficulty 2, 7
• Moderate depression: symptom count, intensity, and impairment fall between mild and severe categories 2, 7
• Severe depression: all or most of the 9 symptoms present with severe functional impairment and marked interference with daily functioning 2, 7

Certain high-risk features automatically classify depression as severe regardless of symptom count: specific suicide plan with clear intent, recent suicide attempt, presence of psychotic symptoms, first-degree family history of bipolar disorder, or severe functional impairment. 7

Critical Diagnostic Pitfalls to Avoid

• Do not diagnose based solely on symptom count without assessing functional impairment—these are only moderately correlated and represent partly independent domains 2, 7
• Do not omit assessment of suicidal ideation (PHQ-9 item 9), as this artificially lowers severity scores and may miss critical risk 2, 7
• Do not fail to rule out bipolar disorder before diagnosing MDD, as antidepressant-related mania qualifies as a manic episode and suggests bipolar disorder 3, 6
• Always identify and treat medical or substance-induced causes of depressive symptoms before attributing symptoms to primary depression 7
• Do not confuse normal grief with MDD without carefully assessing for atypical features 2, 3

Practical Assessment Approach

Use the PHQ-9 as the primary screening tool, with scores of 1-7 indicating minimal symptoms, 8-14 indicating moderate symptomatology, and ≥15 indicating moderate to severe or severe symptomatology. 7

For formal diagnosis, validated structured interviews include the Structured Clinical Interview for DSM-5 (SCID-5) and Mini International Neuropsychiatric Interview (MINI). 2

Nuances in Symptom Requirements

Research has shown that very few patients (approximately 1.5%) meet 5 or more symptom criteria without experiencing either depressed mood or loss of interest/pleasure, and most of these patients still receive a depressive disorder diagnosis. 8 This suggests the requirement for one of these two "main criteria" is clinically sound, though some have argued the diagnostic criteria could be simplified to a straightforward symptom count. 8

Anhedonia is particularly important for discriminating severe from moderate depression, while depressed mood is most reliable for discriminating non-depressed from moderately depressed individuals. 9 The somatic symptom cluster (sleep, appetite, psychomotor, fatigue) tends to predominate in moderate depression, while the non-somatic cluster (worthlessness, guilt, concentration, suicidal ideation) is more prominent in severe depression. 9