The Patient Health Questionnaire (PHQ) was developed as an alternate screening instrument to the Primary Care Evaluation of Mental Disorders (PRIME-MD). The self-administered 16-question PHQ has diagnostic validity comparable to PRIME-MD and includes mood, anxiety, alcohol, eating, and somatoform modules. The PHQ was developed by Robert L. Spitzer, MD, and colleagues, with an educational grant from Pfizer Inc.
The Patient Health Questionnaire 9-item (PHQ-9) is a 9-question less specific version of the PHQ: 8 questions assess symptoms and 1 question assesses functional impairment; the questions are scored on a scale of 0 to 3. This screening instrument identifies depression and panic disorder and assesses stress and functionality, including gender-specific sources of stress.
The full Patient Health Questionnaire (PHQ) and Brief Patient Health Questionnaire (Brief PHQ) can be used to establish provisional diagnoses for selected DSM-IV disorders. The Brief PHQ covers depressive disorders and panic disorders.
The Patient Health Questionnaire-SADS (PHQ-SADS) was developed to reflect that most primary-care patients with depression or anxiety disorders present with somatic complaints; the co-occurrence of somatic, anxiety, and depressive symptoms (the SAD triad) is exceptionally common. Although the PHQ was originally developed to detect 5 disorders, the depression, anxiety, and somatoform modules (in that order) have turned out to be the most popular. The PHQ-SADS includes PHQ-9, GAD-7, and PHQ-15 as well as panic symptoms for PHQ.