What is the best course of treatment for a patient with a Patient Health Questionnaire-9 (PHQ-9) score of 19 and passive suicidal ideation (SI)?

Management of PHQ-9 Score of 19 with Passive Suicidal Ideation

This patient requires immediate referral to psychiatry and/or psychology for formal diagnosis and treatment, combined with urgent safety assessment and interventions to reduce risk of self-harm. 1, 2

Immediate Safety Assessment and Risk Mitigation

Before any other intervention, you must conduct an emergency evaluation for risk of harm to self, as the presence of any suicidal ideation—even passive thoughts—mandates immediate action regardless of the PHQ-9 total score. 1, 2

• Facilitate a safe environment immediately by removing means of self-harm, establishing one-to-one observation if in a clinical setting, and ensuring the patient is not left alone until psychiatric evaluation is completed. 1
• Refer for emergency psychiatric evaluation by a licensed mental health professional if the patient endorses any frequency of thoughts about being better off dead or hurting themselves on PHQ-9 item 9, as this represents acute suicide risk requiring specialist assessment. 1, 2, 3
• Use multiple assessment methods beyond the PHQ-9 to evaluate suicide risk, as no single tool can sufficiently stratify risk level—combine clinical interview with structured assessment to avoid misclassification. 1

Understanding the Clinical Severity

• A PHQ-9 score of 19 indicates moderate to severe depression (score range 15-19), meaning the patient has the majority of depressive symptoms with moderate to marked functional impairment. 1, 2
• The presence of passive suicidal ideation significantly elevates risk, as research demonstrates cumulative one-year suicide attempt risk increases from 0.4% in those reporting "not at all" to 4% in those reporting thoughts "nearly every day," with suicide death risk reaching 0.3% at the highest frequency. 3
• PHQ-9 item 9 has 87.6% sensitivity for detecting suicide risk when validated against the Columbia Suicide Severity Rating Scale, though specificity is only 66.1%, meaning positive responses require further clinical evaluation but should never be dismissed. 4

Mandatory Psychiatric Referral

Make immediate referral to psychiatry and/or psychology for formal diagnosis and treatment planning, as scores ≥15 mandate specialist-level care due to the severity of symptoms and functional impairment. 1, 2

• The referral is urgent, not routine, given the combination of severe depressive symptoms and suicidal ideation—contact the psychiatric service directly rather than scheduling a future appointment. 1, 2
• Ensure the patient is seen within 24-48 hours by arranging emergency or urgent psychiatric consultation, as the risk period for suicide attempt begins immediately and continues for several months. 3

Treatment Considerations Pending Psychiatric Evaluation

• If the patient is not currently on antidepressant medication, initiate treatment immediately while awaiting psychiatric consultation, as delays in treatment for moderate to severe depression worsen outcomes. 2
• Screen for past hypomanic or manic episodes before starting or increasing antidepressants, as undiagnosed bipolar disorder can lead to manic episodes, rapid cycling, or mixed states with antidepressant monotherapy. 2
• Consider ketamine infusion (0.5 mg/kg single dose) for rapid reduction of suicidal ideation if available and appropriate, as evidence shows 55% of patients report no suicidal ideation at 24 hours and 60% at 7 days post-infusion. 1
• Initiate cognitive behavioral therapy (CBT) immediately if accessible, as evidence supports CBT for reducing both suicidal ideation and behavior in patients with depression and self-harm risk. 1

Safety Planning and Monitoring

• Develop a written safety plan with the patient that includes warning signs, internal coping strategies, social contacts for distraction, family members who can help, crisis hotline numbers (988 Suicide & Crisis Lifeline), and means restriction strategies. 1
• Involve family members or support persons in safety planning and monitoring, ensuring they understand warning signs and have emergency contact information. 1
• Schedule reassessment with repeat PHQ-9 within 1-2 weeks after any intervention, with ongoing monitoring at regular intervals or during times of personal transition or health status changes. 1, 2, 5

Critical Pitfalls to Avoid

• Never continue current inadequate treatment without modification if the patient is already on antidepressants, as a PHQ-9 of 19 represents treatment failure requiring dose optimization, medication switch, or augmentation. 2
• Do not rely solely on PHQ-9 item 9 to assess suicide risk, as it has limited specificity (66.1%) and may miss patients with acute suicidal intent who minimize their responses—always conduct a thorough clinical interview. 1, 4
• Never discharge the patient without a concrete safety plan and confirmed psychiatric follow-up, as the risk of suicide attempt is highest in the days to weeks following identification of suicidal ideation. 3, 6
• Avoid assuming passive suicidal ideation is low risk, as the distinction between passive and active ideation is less predictive of outcomes than the frequency and persistence of thoughts, with "passive" thoughts often progressing to active planning. 3, 4

Documentation Requirements

• Document the specific response to PHQ-9 item 9 (frequency of thoughts of death or self-harm), the safety assessment findings, interventions implemented, and the psychiatric referral with expected timeframe. 1, 3
• Record the patient's access to lethal means and any means restriction counseling provided, as this is a critical suicide prevention intervention. 1