Validation of PHQ-2 and PHQ-9 to Screen for Major Depression in the Primary Care Population

Inducing physicians to administer screening instruments for psychiatric illnesses is a complex undertaking. The initial step is to convince physicians that a screening instrument is psychometrically valid. Arroll and colleagues are to be commended, therefore, for generating data needed to inform primary care physicians about the psychometric strengths as well as limitations of the PHQ-2 and PHQ-9. While the data presented by Arroll, et al. regarding the sensitivity, specificity, and other properties of these instruments in primary care practice surely are meaningful, we must also emphasize the need to ascertain the psychometric properties of these instruments when administered elsewhere. Thus, Arroll, et al. note that the PHQ-9’s sensitivity diminishes markedly when administered in cardiology clinics. This possibly results from the distress associated with certain medical illnesses and functional limitations that compromise the ability of screening instruments to correctly detect depression. Rollman, et al. (1), however, report a significantly higher all-cause 12-month mortality rate for hospitalized congestive heart failure patients who screened positive on the PHQ-2. We also question the clinical utility of administering only diagnosis- specific screening instruments, given the high prevalence of co-occurring psychiatric illnesses in primary care practice. Thus, the M-3 (2) which screens for major depression with the same sensitivity and specificity as the PHQ-9, as determined by Arroll, et al., but which also screens for bipolar disorder, PTSD, and generalized anxiety warrants greater attention as we strive to improve the identification of ALL psychiatric illnesses troubling medical patients.

1. Rollman B, Herbeck-Belnap B, Mazumdar S, et al. A positive PHQ-2 depression screen among hospitalized CHF patients predicts 12-month mortality. Psychosom Med 2010; suppl: A141.

2. Gaynes B, DeVeaugh-Geiss J, Weir S, et al. Feasibility and diagnostic validity of the M-3 Checklist: A brief, self-rated screen for depressive, bipolar, anxiety, and pos-traumatic stress disorders in primary care. Ann Fam Med 2010: 8; 160-169.

Competing interests:   None declared