What is primarily assessed by the Patient Health Questionnaire-9 (PHQ-9)?

The Patient Health Questionnaire-9 (PHQ-9) is specifically designed to assess the presence and severity of depression symptoms. It comprises nine questions that reflect the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria for major depressive disorder. Each item corresponds to a symptom of depression, such as mood, interest in activities, sleep patterns, energy levels, self-esteem, concentration, appetite, feelings of guilt or worthlessness, and thoughts of self-harm.

The responses are tailored to help gauge not only the existence of depressive symptoms but also their impact on daily functioning over the previous two weeks. The scoring system quantifies the severity of these symptoms, which assists healthcare providers in diagnosing depression and monitoring treatment progress effectively.

While anxiety levels, substance use severity, and cognitive functioning are important areas of mental health assessment, they are not directly measured by the PHQ-9, making depression symptoms the primary focus of this tool. This specificity is what makes the PHQ-9 a valuable resource in both clinical settings and research regarding mental health.