Phq 8Edit

PHQ-8, short for the Patient Health Questionnaire-8, is a concise, self-administered instrument used to screen for depressive symptoms in clinical settings and research. It draws eight items from the criteria used to define major depressive disorder in the DSM framework, omitting the ninth item that asks about suicidal thoughts. The result is a score from 0 to 24 that helps clinicians gauge whether further assessment or treatment may be warranted. Because it is a screening tool rather than a diagnosis, a high score signals the need for a fuller clinical interview rather than a definitive label.

The PHQ-8 is designed to be quick to complete in busy practices and studies, while still aligning with DSM criteria for depressive symptoms over the prior two weeks. It is commonly used in primary care and mental health settings, and it has been adopted in many research programs and quality-of-care initiatives. Because it relies on self-report, it should be interpreted in the context of a clinician’s judgment, patient history, and, when appropriate, additional assessments such as a full diagnostic interview with Major depressive disorder criteria.

Overview

What it measures

The eight items assess the frequency of core depressive symptoms within the last two weeks. Typical domains include anhedonia (loss of interest or pleasure), depressed mood, sleep disturbance, fatigue, changes in appetite, feelings of worthlessness or inappropriate guilt, concentration problems, and psychomotor changes. Each item is scored from 0 to 3, reflecting how often the symptom has been present. The total score helps indicate the overall burden of depressive symptoms and whether clinical follow-up is advisable. See PHQ-8 for the standardized format and item wording.

Structure and scoring

Eight questions, each scored 0 (not at all) to 3 (nearly every day).
Total score ranges from 0 to 24.
Common interpretation categories are used in practice: minimal or no symptoms, mild, moderate, moderately severe, and severe.
The instrument is intended to screen and monitor symptom change, not to diagnose on its own. For a full diagnostic assessment, clinicians consider the PHQ-8 results alongside other information and, if needed, may refer to a more comprehensive evaluation such as those found in Depression guidelines or a diagnostic interview.

Development and validation

The PHQ-8 emerged as a streamlined cousin to the PHQ-9, preserving the core symptom content while removing the ninth item about suicidal ideation. Development and validation work across multiple languages and settings has demonstrated that the PHQ-8 retains good reliability and validity as a measure of depressive symptom burden. It has been tested in diverse patient populations and is often favored when risk assessment for suicidality is handled separately or when questionnaire length and patient comfort are priorities. See DSM-5 and Patient Health Questionnaire families for the broader context and comparisons to related instruments.

Applications and clinical use

In primary care and clinics

The PHQ-8 is widely used in Primary care to help clinicians identify patients who may benefit from further evaluation or treatment for depression. Its brevity enables routine administration during regular visits, enabling clinicians to track symptom changes over time and to justify treatment decisions with a standardized measure. When results indicate moderate to severe symptoms, clinicians typically perform a broader assessment, review safety considerations, and discuss treatment options, including counseling, psychotherapy, or pharmacotherapy as appropriate. See Screening and Mental health management guidelines for context.

In research and public health

Researchers use the PHQ-8 to estimate the prevalence of depressive symptoms in populations, to monitor trends, and to evaluate the impact of programs designed to improve mental health outcomes. The instrument’s standardized scoring makes it suitable for comparing results across studies and settings, while its shorter form reduces respondent burden in large surveys. See Epidemiology of depression and Quality measures in health care for related topics.

Limitations and controversies

Not a diagnostic tool

Like other screening instruments, the PHQ-8 cannot by itself determine whether someone has a depressive disorder. A high score indicates the need for further assessment, not a final diagnosis. The interpretive process depends on clinical judgment, corroborating information, and sometimes a formal diagnostic interview. See Major depressive disorder for diagnostic criteria and DSM-5 guidelines.

Suicidality assessment

The PHQ-8 excludes the item on suicidal thoughts, which means it does not directly assess suicidality. Clinicians concerned about safety should use the full PHQ-9 or conduct direct risk assessment as part of their clinical workflow. See Suicidal ideation and Suicide resources for guidance.

Cultural and contextual limitations

As with many self-report measures, cultural norms, language differences, health literacy, and stigma can influence how people understand and respond to the items. Some populations may underreport distress due to stigma or differing expressions of psychological distress. Translation accuracy and local norms affect validity, so clinicians should consider cultural context and, when possible, use validated translations or adjunct measures.

Resource and policy considerations

In discussions about health policy and clinical practice, critics worry about routine screening driving unnecessary consultations, anxiety, or overpathologizing ordinary suffering. Proponents counter that systematic screening can uncover untreated depression, enabling timely support and better outcomes. The balance often hinges on how screening is implemented: patient consent, privacy protections, clinician training, referral networks, and follow-up capacity all shape effectiveness and resource use. See Health policy and Screening debates for related themes.