The Patient Health Questionnaire is a self-administered tool.7,8 The 9-item PHQ-9 establishes the clinical diagnosis of depression and can additionally be used to track the severity of symptoms over time.7 The boundaries of the PHQ-9 are as follows:7
PHQ-9 score Provisional diagnosis
1–4 Minimal symptoms
5–9 Mild depression
10–14 Moderate depression
15–19 Moderate to severe depression
>20 Severe depression
Generalised anxiety disorder (GAD) is characterised by excessive anxiety and worry, about numerous events or activities.1 Examples include worrying about household chores, or being late for appointments.1 MDD and GAD are frequently comorbid.1-3,5 The presence of anxiety symptoms in patients with MDD negatively affects response to antidepressant treatment,3 and negatively affects patient quality of life.4 Generalised anxiety/worry is a common feature of depressive disorders, but should be diagnosed separately if the excessive worry has occurred outside the course of the depressive illness or is sufficiently severe to warrant clinical attention.1
References:
1.American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. Fifth Edition – text revision. © American Psychiatric Association, 2022.
2.Fava M, Rush AJ, Alpert JE, et al. Difference in treatment outcome in outpatients with anxious versus nonanxious depression: a STAR*D report. Am J Psychiatry 2008; 165 (3): 342–351.
3.Fava M, Rankin MA, Wright EC, et al. Anxiety disorders in major depression. Compr Psychiatry 2000; 41 (2): 97–102.
4.Zhou Y, Cao Z, Yang M, et al. Comorbid generalized anxiety disorder and its association with quality of life in patients with major depressive disorder. Sci Rep 2017; 7: 40511.
5.Kessler RC. The prevalence of psychiatric comorbidity. In: Wetzler S, Sanderson WC (eds). An Einstein Psychiatry Publication, No. 14. Treatment Strategies for Patients with Psychiatric Comorbidity. John Wiley & Sons Inc. 1997.
6.Saha S, Lim CCW, Cannon DL, et al. Co-morbidity between mood and anxiety disorders: a systematic review and meta-analysis. Depress Anxiety 2021; 38 (3): 286–306.
7.Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med 2001; 16 (9): 606–613.
8.Spitzer RL, Kroenke K, Williams JBW. Validation and utility of a self-report version of PRIME-MD: the PHQ primary care study. JAMA 1999; 282 (18): 1737–1744.
