[Prevalence and diagnosis of depression in primary care. A critical comparison between PHQ-9 and GPs' judgement].

Objective: Up to 50 % of patients suffering from major depression are not recognised by their general practitioners. On the other hand general practitioners do rate some of their patients as depressive despite the fact that psychiatric diagnostic instruments do not. In this study we wanted to not only analyse the number and proportion of concordant diagnoses between GP and an established psychiatric diagnostic instrument (PHQ-9), but also to analyse the modalities of non-concordant diagnostic classifications.