At what Patient Health Questionnaire-9 (PHQ-9) score does a patient need a mental health referral?

PHQ-9 Score Requiring Mental Health Referral

A PHQ-9 score of 8 or higher requires mental health referral for diagnostic confirmation, with scores of 15 or higher mandating immediate referral to psychology and/or psychiatry for formal diagnosis and treatment. 1, 2

Score-Based Referral Algorithm

PHQ-9 Score 1-7 (Minimal/Mild Depression)

• No mental health referral needed for routine cases 1
• Provide supportive care, patient education, and schedule reassessment 3
• Critical exception: If item 9 (self-harm thoughts) is endorsed at any frequency, immediate emergency psychiatric evaluation is mandatory regardless of total score 1, 3

PHQ-9 Score 8-14 (Moderate Depression)

• Make referral to psychology or psychiatry for determination of diagnosis 1
• This score indicates most depressive symptoms are present with mild to moderate functional impairment 1, 2
• The cutoff of 8 is specifically supported by meta-analysis data showing optimal diagnostic accuracy (sensitivity 88%, specificity 88%) 2, 4
• Consider low-intensity interventions while awaiting mental health evaluation, including guided self-help based on cognitive behavioral therapy or structured physical activity programs 2, 5

PHQ-9 Score 15-27 (Moderately Severe to Severe Depression)

• Immediate referral to psychology and/or psychiatry for diagnosis and treatment is mandatory 1, 2
• These patients have the majority of depressive symptoms with moderate to marked functional interference 1
• High-intensity interventions delivered by licensed mental health professionals are required 2

Critical Safety Considerations

Emergency Evaluation Required

• Any patient at risk of harm to self or others requires immediate referral for emergency evaluation by a licensed mental health professional, regardless of PHQ-9 score 1
• Facilitate safe environment and one-to-one observation if self-harm risk is present 1
• The presence of psychosis, severe agitation, or confusion (delirium) also warrants emergency evaluation 1

Common Pitfalls to Avoid

• Never omit item 9 (self-harm assessment) - this artificially lowers scores and misses critical risk information 2, 3
• Do not underestimate a score of 8-14 as merely "mild" - this represents clinically significant depression requiring active treatment, not watchful waiting 2, 5
• Failing to complete the full PHQ-9 when the initial 2-item screen (anhedonia and depressed mood) shows either item scoring ≥2 2
• Do not initiate antidepressant medication or formal psychotherapy for scores of 1-7, as this represents overtreatment of mild symptoms that typically respond to supportive care 3

Evidence Quality and Context

The American Society of Clinical Oncology 2023 guideline provides the most authoritative framework, establishing the cutoff of 8 based on validated diagnostic accuracy studies 1. This is corroborated by meta-analysis data showing acceptable diagnostic properties for cutoff scores between 8-11, with no substantial differences in pooled sensitivity and specificity across this range 4. The original PHQ-9 validation study demonstrated that a score ≥10 had 88% sensitivity and 88% specificity for major depression 6, though the ASCO guideline's recommendation of 8 as the referral threshold provides earlier intervention opportunity 1.

Special Populations

• The PHQ-9 loses accuracy in patients with cognitive impairment - use alternative assessment methods in this population 2
• Use culturally sensitive assessments when possible 1, 2
• Tailor evaluation for patients with learning disabilities or cognitive impairments 2
• Detection of depression in older adults is particularly challenging and may require additional clinical judgment 2