Depression Scale Scoring and Clinical Interpretation
The PHQ-9 should be your primary screening tool, with scores ≥10 indicating clinically significant depression requiring further evaluation, while the HAM-D (7–17 mild, 18–24 moderate, ≥25 severe) and BDI-II (≥20 clinical depression) serve as validated alternatives for severity assessment. 1, 2
PHQ-9 (Patient Health Questionnaire-9)
Scoring Method
- Nine items, each rated 0–3 (0="not at all," 1="several days," 2="more than half the days," 3="nearly every day"), yielding a total range of 0–27 2, 3
- Sum all item scores to obtain the total score 2
Score Interpretation
- ≥10: Standard cutoff for major depressive disorder with 88% sensitivity and 88% specificity 2, 3
- 5–9: Mild depression 3
- 10–14: Moderate depression 3
- 15–19: Moderately severe depression 3
- ≥20: Severe depression 3
Critical Safety Action
- Any affirmative response to item 9 (suicidal ideation) mandates immediate suicide-risk evaluation, regardless of total score 2, 1
- Patients at risk of self-harm require urgent emergency psychiatric referral 2, 1
Clinical Utility
- The PHQ-9 is recommended as the first-line assessment tool by ASCO guidelines 1
- Alternative cutoffs have been studied: PHQ-9 ≥12 provides 77% sensitivity and 79% specificity for moderate depression, while ≥15 achieves 89% sensitivity and 83% specificity for severe depression 4
HAM-D (Hamilton Depression Rating Scale)
Scoring Method
- 17-item clinician-administered scale assessing DSM-IV depression criteria 1
- Requires trained diagnostician to administer 1
Score Interpretation
Alternative Guideline Thresholds
- ASCO guidelines cite 7–17 as mild, 18–24 as moderate, and ≥25 as severe 1
- The discrepancy reflects different validation studies, but the more recent 2013 research supports the 0–7/8–16/17–23/≥24 cutoffs 5
Clinical Considerations
- Domains assessed include low mood, insomnia, agitation, anxiety, and weight loss 1
- Requires professional administration, limiting its use for routine screening 1
BDI-II (Beck Depression Inventory-II)
Scoring Method
- 21-item self-report scale with scores ranging 0–63 1
- Assesses behavioral, cognitive, and somatic components of depression including suicidal ideation 1
Score Interpretation
- ≥20: Suggestive of clinical depression per ASCO guidelines 1
- Alternative research suggests ≥23 provides 74% sensitivity and 75% specificity for moderate depression 4
- ≥28 achieves 83% sensitivity and 80% specificity for severe depression by NICE criteria 4
Clinical Utility
- Includes assessment of suicidal ideation as part of the standard items 1
- Covers behavioral, cognitive, and somatic depression components comprehensively 1
MADRS (Montgomery-Åsberg Depression Rating Scale)
Scoring Method
- 10-item clinician-rated scale with total scores ranging 0–60 6
- Each item scored 0–6 based on severity 6
Score Interpretation
- While the evidence provided does not specify exact cutoffs, conversion equations exist to translate MADRS scores to other scales 6
- These conversion equations work well for group-level data but show high variability at the individual patient level 6
Clinical Considerations
- Conversion equations between MADRS, PHQ-9, BDI-II, and other scales should be used cautiously for individual patients due to significant prediction errors 6
- More appropriate for research comparisons and meta-analyses than individual clinical decision-making 6
Additional Validated Scales
CES-D (Center for Epidemiological Studies–Depression Scale)
- 20-item self-report scale (10-item short form available) 1
- ≥16: Moderate to severe depressive symptomatology 1
- Relatively unaffected by physical symptoms, making it useful in medically ill populations 1
GDS (Geriatric Depression Scale)
- 30-item scale (15-item short form available) specifically designed for elderly patients 1
- ≥19 on full scale or ≥5 on short form: Suggestive of depression requiring follow-up 1
- Focuses on positive and negative affective symptoms common in older adults 1
HADS (Hospital Anxiety and Depression Scale)
- 14-item self-report measure with separate anxiety and depression subscales 1
- ≥8 on either subscale: Indicative of caseness for disorder by ICD-9 criteria 1
- Physical symptom items are excluded, making it useful in medical populations 1
Clinical Management Algorithm
For Scores Indicating Moderate to Severe Depression (PHQ-9 ≥10)
- Conduct comprehensive diagnostic assessment to clarify the nature and extent of depressive symptoms and presence of mood disorder 1, 2
- Evaluate for medical or substance-induced causes (e.g., interferon, corticosteroids, hypothyroidism) and treat underlying conditions first 1, 2
- Consider referral to psychiatry, psychology, or equivalently trained professional for moderate to severe cases 1, 2
Treatment Initiation
- First address medical causes of depressive symptoms (unrelieved pain, fatigue) and delirium (infection, electrolyte imbalance) 1
- Use pharmacologic and/or non-pharmacologic interventions (psychotherapy, cognitive-behavioral therapy, exercise) delivered by appropriately trained individuals 1
Common Pitfalls and Caveats
Cross-Cultural Validity
- PHQ-9 has been translated into over 70 languages, but validation varies across populations 7
- Differences in item functioning have been documented between language versions, particularly for appetite, sleep, and psychomotor items 7
- Under-detection of depression in low- and middle-income countries remains a significant concern 7
Scale Selection Considerations
- PHQ-9 demonstrates superior discriminatory performance (AUC 0.90–0.93) compared to HADS-D (AUC 0.84–0.89) and BDI-II (AUC 0.86–0.90) 4
- However, none of these scales align perfectly with HAM-D cutoffs, which inform most treatment trial evidence 4
- Recent COSMIN evaluation suggests PROMIS-D may have superior psychometric properties across diverse populations, though it is less widely adopted 8