Search tips
Search criteria 


Logo of brjgenpracRCGP homepageJ R Coll Gen Pract at PubMed CentralBJGP at RCGPBJGP at RCGP
Br J Gen Pract. 2007 October 1; 57(543): 835–836.
PMCID: PMC2151819

Diagnosing depression

Kaj Sparle Christensen, PhD, Senior Researcher
Research Unit for General Practice, Vennelyst Boulevard 6, 8000 Aarhus C, Denmark. E-mail:
Per Fink, Director, Assistant Professor

We have some concerns about the validity of the study by Gilbody, et al.1 Patients were recruited for a randomised controlled trial of collaborative care for depression in primary care. Thirty-six of 96 (93 in the abstract) patients (37.5 %) were diagnosed with major depressive disorder according to SCID. Such high prevalence indicates that patients were not randomly chosen from practices. Receiver-operating curve statistics was applied on this obviously highly-selected group of patients. This is misleading; any depression screening instrument may demonstrate excellent performance in such groups. For instruments to prove useful in general practice, statistics should be based on representative practice population samples.24


1. Gilbody S, Richards D, Barkham M. Diagnosing depression in primary care using self-completed instruments: UK validation of PHQ–9 and CORE–OM. Br J Gen Pract. 2007;57(541):650–652. [PMC free article] [PubMed]
2. Sackett DL, Haynes RB, Guyatt GH, Tugwell P. Clinical epidemiology: a basic science for clinical medicine. 2nd edn. Boston, MA: Little, Brown & Co.; 2000.
3. Bossuyt PM, Reitsma JB, Bruns DE, et al. Towards complete and accurate reporting of studies of diagnostic accuracy: the STARD initiative. Fam Pract. 2004;21(1):4–10. [PubMed]
4. Smidt N, Rutjes AW, van der Windt DA, et al. The quality of diagnostic accuracy studies since the STARD statement: has it improved? Neurology. 2006;67(5):792–797. [PubMed]

Articles from The British Journal of General Practice are provided here courtesy of Royal College of General Practitioners