4.The Patient Health Questionnaire-9 (PHQ-9)

The Patient Health Questionnaire-9, often referred to as the PHQ-9, is a relatively recent addition to the toolkit of clinical psychologists. Developed by Kroenke and Spitzer in 2001, this scale is designed to assess the severity of depressive symptoms in individuals. It has gained widespread acceptance and use as a reliable instrument for diagnosing and tracking depression.

Items of the PHQ-9

The PHQ-9 consists of nine items, each of which focuses on a specific depressive symptom. Individuals are asked to rate the frequency and severity of each symptom over the past two weeks. Some example items include:

"Little interest or pleasure in doing things."

"Feeling down, depressed, or hopeless."

"Trouble falling or staying asleep, or sleeping too much."

"Feeling tired or having little energy."

The PHQ-9 has been instrumental in the early diagnosis and monitoring of depression, enabling clinicians to tailor treatment strategies and track treatment progress with precision.