ng active case-finding. The categorisation by GPs, however, does reflect what is known about depression (being more common in women and in areas of greater deprivation). It reinforces the suggestion that GPs may often choose not to use formal psychiatric criteria to define people’s illnesses.23 The findings of epidemiological studies, using standardised diagnostic instruments, may not easily be compared with routine clinical practice, as different diagnostic criteria are being applied. This again raises issues regarding the diagnostic validity of depression diagnoses.
Primary care is the place where most people with depression are managed, but the debate over the identification and treatment of depression continues.23 Epidemiologists and psychiatrists have called for the better identification and treatment of depression in light of its high reported prevalence and associated morbidity.33 However, the high lifetime prevalence of depression34 may also suggest that in many cases depression is a normal part of life.23,35 This may be reflected in the ways in which GPs record their findings. Currently the evidence that the identification of depression in clinical practice leads to better long-term outcomes is contested.35,36
Clinical data-sets may become a valuable tool in examining depression and its management in primary care. However, further work on the validation of recorded diagnoses is required to allow appropriate exploitation of electronic records. The combined incidence of diagnoses and symptoms remained stable, indicating that GPs may have recorded similar disorders differently over time. Research needs to address why GPs are using symptom codes more than diagnostic codes. Our study pre-dates the introduction of incentive payments for GPs in April 2006 to record depression as part of the National Health Service’s Quality and Outcomes Framework (QoF),37 which may have further altered coding. Future work should examine the impact of the recommended use of psychiatric screening instruments on identification and classification of depression, as advocated in QoF.
The Department of Primary Care and Population Health, University College London holds a license to conduct analysis on THIN. The Departmental THIN/GPRD Executive Committee reviewed and approved the study protocol, but had no involvement in the analysis, interpretation or decision to submit for publication. K.W. and I.P. were supported by a Special Training Fellowship in Health Services Research from the Medical Research Council (UK). This sponsor had no involvement in the study design, data collection, analysis, interpretation or decision to submit for publication.
We would like to thank Amir Islam, data manager, who extracted the data.
- Received August 20, 2008.
- Revision received June 22, 2009.
- Accepted June 25, 2009.
- © 2009 Royal College of Psychiatrists