PHQ-9

The PHQ-9 is a short, nine-question form used to screen for and measure depression. The letters stand for Patient Health Questionnaire 9-item scale.

This term is specific to research interpretation and is defined on AnxietyResearch. Shrinktionary, the network's language layer, doesn't currently carry a canonical entry for it.

The PHQ-9 asks how often, over the last two weeks, a person was bothered by symptoms of depression, such as low mood, loss of interest, sleep changes, and low energy. Each item is scored 0 to 3, for a total of 0 to 27. It's the depression counterpart to the GAD-7, and the two are often used together.

Anxiety and depression overlap often, so anxiety research and anxiety clinics frequently track depression at the same time. Pairing the PHQ-9 with the GAD-7 gives a fuller picture than either alone. The PHQ-9 also includes a question about thoughts of self-harm, which makes it useful for safety screening.

A clinic treating a person for anxiety also has them complete the PHQ-9, because comorbid depression would change the treatment plan.

Like the GAD-7, the PHQ-9 is a screening and tracking tool, not a diagnosis. The self-harm question should always be reviewed by a clinician when a person endorses it. A score is a starting point for a conversation, not an endpoint.