Patient Health Questionnaire-9 - Adult (PHQ-9)

Major Depressive Disorder (MDD) is one of the most common mental health disorders in the United States (Maurer, Raymond & Davis, 2018). The Patient Health Questionnaire-9 (PHQ-9) is a 9-item validated screening tool and a symptom severity assessment scale that assists clinicians, typically primary care and mental health settings, with rapid screening for the presence of a clinically significant depressive disorder. The PHQ-9 can assist clinicians in making a diagnosis of depression, quantifying depression symptoms, and monitoring severity and treatment efficacy. Higher scores are associated with decreased functional status and symptom-related difficulties. 

However, the PHQ-9 is prone to high false-positive rates in primary care settings with one meta-analysis found that only 50% of patients screening positive actually has major depression (Levis et al., 2019). Therefore, when screening for possible depression, the diagnosis ought to be confirmed using DSM-5 criteria. Maurer et al. (2018) summarizes the use of the PHQ-9 as a screening tool and its relationship to the DSM-5 diagnostic criteria for Major Depressive Disorder. Further, root causes and other mental health disorders ought to be considered. PHQ-9 scores > 9 had a sensitivity and specificity of 88% for major depression. A tip sheet highlights additional criteria when using the PHQ-9 to make a tentative depression diagnosis. 

The Patient Health Questionnaire-9 (PHQ-9) is a 9-item validated screening tool and a symptom severity assessment scale that assists clinicians, typically primary care and mental health settings, with rapid screening for the presence of a clinically significant depressive disorder. Higher scores are associated with decreased functional status and symptom-related difficulties. The last item, How difficult have these problems made it for you to do your work, take care of things at home, or get along with other people, is not included in the score, but is a good indicator of the patient’s global impairment and can be used to track treatment response.

Scoring & Recommendations

The first 7 questions will answer with one of the following:

Additional Considerations

PHQ-9 scores > 9 had a sensitivity and specificity of 88% for major depression. A tip sheet highlights additional criteria when using the PHQ-9 to make a tentative depression diagnosis. However, when screening for possible depression, the diagnosis ought to be confirmed using DSM-5 criteria. Maurer et al. (2018) summarizes the use of the PHQ-9 as a screening tool and its relationship to the DSM-5 diagnostic criteria for Major Depressive Disorder. Further, root causes and other mental health disorders ought to be considered. 

Management

The clinician ought to rule out physical causes of symptoms, normal bereavement, stress, chronic illness and a history of a manic/hypomanic episode.

Some possible root causes of depression

• Blood sugar dysregulation and obesity (Lee, 2016; Calkin, 2019)
• Infection: A few examples -
  • Lyme disease (Bransfield, 2018)
  • Toxoplasma gondii (Hsu, 2014)
• Sedentary lifestyle (Stancykiewicz, 2019)
• Sleep deprivation and artificial light exposure (Figueiro, 2011; Gooley, 2011)
• Social isolation (Uchino, 2006; Cacioppo, 2002)
• Environmental exposure (A few examples)  
  • Indoor mold exposure (Ratnaseelan, 2018; Doi, 2011)
  • Dietary triggers: Consider mold sensitivity from food or the environment. Foods such as coffee, peanuts and grains can have high levels of mold. Many other food sensitivities or allergies can also play a role. A food journal and an elimination diet may help sort this out.
• Autoimmune Disorders
• Stress

Therapeutic modalities that may reduce depression-related symptoms include:

• Psychotherapy 
  • Cognitive behavioral therapy
  • Somatic experiencing therapy
  • Eye Movement Desensitization and Reprocessing (EMDR)
  • Vagus nerve stimulation

• Relaxation therapies
  • Meditation 
  • Mindfulness-based stress reduction and breathing techniques
  • Yoga

• Complementary and alternative medicine
  • Acupuncture
  • Massage
  • Sound therapy
  • Aromatherapy

The PHQ-9 is a screening tool used by health practitioners to determine initial symptom severity and monitor effect of treatment over time and does not replace a clinical assessment and diagnosis.

Ask: How often do you feel bothered by the following over the past 2 weeks?