There is a paucity of data describing how general practitioners (GPs) label or record depression.
To determine incidence and sociodemographic variation in GP-recorded depression diagnoses and depressive symptoms.
Annual incidence rates calculated using data from 298 UK general practices between 1996 and 2006, adjusted for year of diagnosis, gender, age and deprivation.
Incidence of diagnosed depression fell from 22.5 to 14.0 per 1000 person-years at risk (PYAR) from 1996 to 2006. The incidence of depressive symptoms rose threefold from 5.1 to 15.5 per 1000 PYAR. Combined incidence of diagnoses and symptoms remained stable. Diagnosed depression and symptoms were more common in women and in more deprived areas.
Depression recorded by general practitioners has lower incidence rates than depression recorded in epidemiological studies, although there are similar associations with gender and deprivation. General practitioners increasingly use symptoms rather than diagnostic labels to categorise people’s illnesses. Studies using standardised diagnostic instruments may not be easily comparable with clinical practice.
Depression will be the second highest cause of disease burden globally by 2020.1 The cost of depression has recently been estimated at $83.1 billion in the USA2 and £9 billion in England,3 most of which was attributable to time off work. Epidemiological surveys suggest that the prevalence of depression has risen in the USA,4,5 although UK survey data has not shown similar changes.6 Antidepressant prescribing has risen in the USA and UK over the past decade.3,7 Data from six European countries8 reported prevalence rates of 13.9% in women and 8.5% in men of DSM–IV major depression in family practice attendees in 2004–2005.
The diagnostic validity of depression is a cause of much debate, and increasingly the concept is being questioned. Psychiatric research classifies psychological disorders according to defined criteria, such as those in the DSM–IV9 or ICD–10.10 However, primary care depression may be described as an everyday problem of practice, rather than an objective diagnostic category.11 Standardised diagnostic interviews are not used in primary care to diagnose depression, and it is known that more severe depression is more likely to be recognised in primary care settings.12,13 A recent meta-analysis14 found that non-psychiatric physicians’ recognition of depression had a low sensitivity (36.4%) but high specificity (83.7%) for ‘true’ cases measured using standardised diagnostic instruments; however, non-psychiatric physicians may deliberately avoid labelling people with mild symptoms as being depressed. Therefore, categorical approaches to diagnosis have been questioned in favour of a multidimensional approach,15 which may be more relevant to primary care.12
Epidemiological surveys have shown that depression diagnoses are higher in women, older people and those living in deprived areas. We do not know whether this is mirrored in the rates of general-practitioner (GP) recording of depression diagnoses and depressive symptoms. There are few data on depression incidence in primary care and primary care recording of depression, in contrast to the wealth of epidemiological data on prevalence.16 We examined a large UK primary care database to determine the incidence rates of recorded depression diagnoses and depressive symptoms in attenders from 1996 to 2006. We also determined whether there were differences in incidence of recording of diagnoses or symptoms by sociodemographic factors. The study was given a favourable opinion by the London Medical Research Ethics Committee (07/MRE02/5).
We used data from 298 UK general practices, providing two or more years of data to The Health Improvement Network (THIN) from January 1996 to March 2006. We only used practices meeting standards for acceptable levels of data recording. The total registered patient population during this time period was 4 986 111 people, comprising 21.6 million years of follow-up.
The Health Improvement Network (THIN) electronic recording scheme is o