Depression is prevalent, costly and often undertreated.

Depression has a community prevalence of 10% (Singleton et al, 2001), and is associated with physical morbidity and social impairment (Spitzer et al, 1995; Cassano & Fava, 2002). By 2020, depression is expected to become the second highest cause of disease burden worldwide (Murray & Lopez, 1997). The annual cost of depression in England alone was estimated at £9 billion in 2000, of which 90% was attributable to an estimated 110 million lost working days (Thomas & Morris, 2003). Unmet need for treatment (Bebbington et al, 2000; Singleton et al, 2001) is even more apparent when considering only cases of severe disorder (Demyttenaere et al, 2004; Wang et al, 2005).

There is a socioeconomic gradient in the prevalence of depression (Lorant et al, 2003), and those with the lowest socio-economic status might also be the least likely to receive and/or adhere to effective treatment (Acheson, 1998). The aim of this study was to quantify socio-economic inequalities in the delivery of and adherence to treatments of proven clinical effectiveness. We hypothesised that there would be an ‘inverse care law’ – a statistically significant association between low socio-economic status and (under-) treatment of depression after adjusting for the severity of depressive episode.

Aims To test the hypothesis that people with low socio-economic status are least likely to receive and adhere to evidence-based treatments for depression, after controlling for clinical need.

Method Individuals with an ICD–10 depressive episode in the past12 months (n=866) were recruited from 7271 attendees in 36 general practices in England and Wales. Depressive episodes were identified using the12-month Composite International Diagnostic Interview. Treatment receipt and adherence were assessed by structured interview, and rated using evidence-based criteria.

Results We identified 332 individuals (38.3%) who received and adhered to evidence-based treatment. There were few socio-economic differences in treatment allocation. Although those without educational qualifications were least likely to receive psychological treatments (OR = 0.55,95% CI 0.34–0.89, P = 0.02), this association was not statistically significant after adjusting for depression severity.

Conclusions We found no evidence of inverse care in the treatment of moderate and severe depression in primary care in England and Wales.

SCOTT WEICH, MD
Health Sciences Research Institute, Warwick Medical School, University of Warwick, Coventry

IRWIN NAZARETH, PhD
Department of Primary Care and Population Sciences, Royal Free and University College Medical School, London

LOUISE MORGAN, PhD
Dr Foster Ltd, London

MICHAEL KING, PhD
Department of Mental Health Sciences, Royal Free and University College Medical School, London

Correspondence: Professor Scott Weich, Health Sciences Research Institute, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK. Email: .(JavaScript must be enabled to view this email address)

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