PHQ‑9 Administration and Interpretation Guidelines

Instrument Overview

• The PHQ‑9 is a nine‑item self‑report questionnaire assessing depressive symptoms over the past two weeks; each item is scored 0–3, yielding a total score ranging from 0 to 27. 1

Screening Procedure

• Initial screening should begin with the PHQ‑2 (the first two items) for all patients. 2
• If the PHQ‑2 total is 0–1, no further depression screening is required. 2
• If the PHQ‑2 total is 2–3, the full PHQ‑9 should be administered. 2
• This phased approach limits full PHQ‑9 completion to approximately 25–30 % of patients. 2
• The full PHQ‑9 includes seven additional items covering sleep problems, low energy, appetite changes, low self‑view, concentration difficulties, psychomotor changes, and thoughts of self‑harm. 1
• The self‑administered paper form is the most common administration format. 1

Scoring and Interpretation

• For cancer patients and similar populations, a cut‑off score of 8 (rather than the traditional 10) is recommended. 2
• Score 1–7: No or mild depressive symptoms; no immediate intervention required. 2
• Score 8–14: Moderate/sub‑threshold depressive symptoms with mild‑to‑moderate functional impairment; consider psychological consultation. 2
• Score 15–19: Moderate‑to‑severe symptoms with moderate functional interference; referral for psychiatric evaluation is advised. 2
• Score 20–27: Severe symptoms with marked functional disruption; urgent psychiatric referral is indicated. 2
• The lower cut‑off of 8 is supported by validation studies in cancer outpatients and meta‑analyses. 2

Safety Considerations (Suicidality)

• Item 9 specifically assesses thoughts of self‑harm. 2
• Any endorsement of suicidality requires immediate evaluation of frequency and specificity. 2
• If the patient is at risk of harming self or others, emergency mental‑health referral, provision of a safe environment, one‑to‑one observation, and harm‑reduction interventions are mandatory. 2
• Do not omit Item 9; exclusion lowers total scores, may miss severe cases, and reduces predictive validity. 2

Timing of Screening

• Depression screening should be performed at multiple time points, including:
  
  • At initial diagnosis or start of treatment,
  • At regular intervals during treatment,
  • At 3, 6, and 12 months post‑treatment,
  • At diagnosis of disease recurrence or progression,
  • When approaching end‑of‑life, and
  • During personal transitions or family crises. 3

Cultural and Linguistic Adaptations

• Item functioning may vary across languages and cultures, particularly for appetite, sleep, and psychomotor items. 4
• Use culturally sensitive assessments whenever possible. 5

Special Populations

• Adapt the PHQ‑9 for individuals with learning disabilities or cognitive impairments. 5
• Be aware of the difficulty in detecting depression among older adults. 5

Follow‑Up Actions Based on Scores

• Scores 8–14 (moderate): Seek consultation with psychology or psychiatry to determine diagnosis. 2
• Scores 15–27 (moderate‑to‑severe or severe): Refer to psychology and/or psychiatry for diagnosis and treatment. 2
• Before treating depressive symptoms, first address potential medical contributors such as uncontrolled pain, fatigue, infection‑related delirium, or electrolyte disturbances. 1

Guidelines for Managing a PHQ‑9 Score of 8 in Oncology Patients

Score Interpretation and Clinical Significance

• A PHQ‑9 score of 8 falls within the moderate symptom range (8–14) and indicates sub‑threshold depressive symptoms with mild‑to‑moderate functional impairment, warranting psychiatric or psychological evaluation. 6, 7
• In cancer and other medically ill populations, a cutoff of 8 is recommended instead of the traditional cutoff of 10, because it improves diagnostic accuracy for depression in these groups. 6
• Validation studies in cancer outpatients and meta‑analyses support the lower cutoff of 8 as providing better sensitivity and specificity for detecting clinically significant depression. 6

Typical Clinical Presentation at This Score

• Patients scoring 8 usually exhibit most depressive symptoms but may not meet full criteria for major depressive disorder. 6, 7
• Functional impairment is typically mild to moderate, affecting daily activities. 6, 7
• Sub‑threshold depressive symptoms can still markedly reduce quality of life. 6

Immediate Clinical Actions

• Prompt referral to a psychologist or psychiatrist for formal diagnostic determination is advised. 6, 7
• Collect a comprehensive history focusing on prior mood disorders, comorbid anxiety, substance use, chronic medical illnesses, disease recurrence or progression, social isolation, unemployment, and lower education level. 7
• Evaluate the patient’s coping skills and access to social and financial resources. 7

Treatment Considerations

• Before initiating depression‑specific therapy, address reversible medical contributors such as uncontrolled pain, fatigue, infection‑related delirium, or electrolyte disturbances. 8
• Low‑intensity psychosocial interventions are appropriate, including structured group therapy led by licensed mental‑health professionals, individual cognitive‑behavioral therapy, or behavioral activation strategies. 7
• Ongoing monitoring for symptom worsening should trigger escalation of care (e.g., higher‑intensity psychotherapy or pharmacotherapy). 7

Suicidality Assessment

• Item 9 of the PHQ‑9 (thoughts of self‑harm) must be evaluated regardless of the total score. 6
• Any endorsement of suicidal ideation requires immediate assessment of frequency and specificity. 7
• When self‑harm risk is identified, an emergency mental‑health referral, provision of a safe environment, and one‑to‑one observation are mandatory. 6, 7

Screening Follow‑Up

• Repeat PHQ‑9 screening at regular intervals during ongoing cancer treatment. 6, 7
• Additional screenings are recommended at 3, 6, and 12 months after treatment completion, at disease recurrence or progression, and during personal transitions or family crises. 7