Major Depressive Disorder: Diagnostic Criteria and Symptoms
Major depressive disorder requires at least 5 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). 1
Core Diagnostic Requirements
The diagnosis of MDD mandates the following structure 1:
Primary Criterion (At Least One Required)
- Depressed mood most of the day, nearly every day (in children and adolescents, this may present as irritable mood rather than sadness) 1
- Markedly diminished interest or pleasure in all, or nearly all, activities most of the day, nearly every day (anhedonia) 1
Additional Symptoms (Need 4 More from This List)
Neurovegetative symptoms (most common in clinical depression) 2:
- Sleep disturbance: Insomnia or hypersomnia nearly every day 1, 3
- Appetite/weight changes: Significant weight loss when not dieting or weight gain (>5% body weight in a month), or increased/decreased appetite nearly every day; in children and adolescents, includes failure to make expected weight gains 1
- Energy depletion: Fatigue or loss of energy nearly every day 1, 3
Psychomotor symptoms (less common but highly specific) 2:
- Psychomotor agitation or retardation nearly every day, observable by others (not merely subjective feelings of restlessness or being slowed down) 1
- Diminished ability to think or concentrate, or indecisiveness, nearly every day 1
- Feelings of worthlessness or excessive/inappropriate guilt (which may be delusional) nearly every day 1
Suicidal ideation 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
The diagnosis cannot be made if 1:
- Symptoms meet criteria for a mixed episode (simultaneous manic and depressive features) 1
- Symptoms are due to direct physiologic effects of a substance (drug of abuse, medication) or general medical condition (e.g., hypothyroidism) 1
- Symptoms are better accounted for by bereavement, unless symptoms persist longer than 2 months OR are characterized by marked functional impairment, morbid preoccupation with worthlessness, suicidal ideation, psychotic symptoms, or psychomotor retardation 1
Functional Impairment Requirement
The symptoms must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning. 1, 4 This distinguishes MDD from subsyndromal or minor depression, which involves fewer symptoms and less functional impact 3.
Clinical Presentation Patterns
Most Common Symptoms
Research demonstrates that sleep disturbance, loss of energy, and appetite changes are the most frequently reported symptoms in MDD 2. These vegetative symptoms appear more central to clinical depression than cognitive symptoms like worthlessness or guilt 2.
Least Common but Highly Specific Symptoms
Psychomotor changes and feelings of worthlessness are less common but serve as strong indicators when present 2. Psychomotor change is the best single indicator of MDD when present 2.
Adolescent-Specific Presentations
In children and adolescents, watch for 5:
- Irritable or cranky mood instead of depressed mood 1, 5
- Preoccupation with song lyrics suggesting life is meaningless 5
- Loss of interest in sports, video games, activities with friends 5
- Excessive late-night TV or refusal to wake for school 5
- Talk of or efforts to run away from home 5
- Persistent boredom 5
- Oppositional and negative behavior 5
- Poor school performance or frequent absences 5
Duration and Temporal Pattern
Symptoms must be present during the same 2-week period and represent a change from previous functioning. 1, 3, 4 This distinguishes an acute depressive episode from chronic personality traits or adjustment reactions 3.
Common Clinical Pitfall
The DSM structure implies that some patients might meet 5 of 9 criteria without experiencing depressed mood or anhedonia, but research shows this occurs in only 1.5% of cases, and most of these patients still have a depressive disorder diagnosis 6. In practice, virtually all patients with 5 or more symptoms will have either depressed mood or anhedonia present 6.