Frequent attendance and the concordance between PHQ screening and GP assessment in the detection of common mental disorders

Abstract

Frequent Attenders (FAs) have high rates of both common mental disorders (CMD) and physical disorders, partly justifying this service use behaviour. This study examines both case and non-case concordance between CMDs as estimated by a self-report screening questionnaire and as rated by the general practitioner (GP), in FAs compared to Other Attenders (OAs). 2275 patients of an overlapping sample of 55 GPs from 2 surveys performed 10 years apart, completed in the waiting room the Patient Health Questionnaire (PHQ) and Client Service Receipt Inventory on 6-month service use. For each patient, the GP rated mental health on a 0-4 scale, with a clear indication that scores of 2 and above referred to caseness. PHQ-CMDs included major and other depressive, anxiety, panic, and somatoform disorders, identified using the original PHQ DSM-IV criteria-based algorithms. FA was defined as the top 10% of attenders in age, sex and survey-year stratified subgroups. FAs had higher rates of PHQ-CMDs (42% versus 23% for OAs, p < .0001). They reported more personal and social problems, disability and had higher GP-rated physical illness. Survey-day antidepressant/anxiolytic medication prescription was higher for FAs (p < .0001), with (p = .02) but also without a CMD (p < .0001). Both GP/PHQ case and non-case concordance differed between FAs and OAs, with a non-case concordance odds ratio of 0.5 (95% CI: 0.3-0.7, p = .001) for FAs compared to OAs. Despite a greater likelihood of GPs detecting CMDs in FAs, our findings suggest a potential risk of 'over-detection' of patients not reaching CMD threshold criteria among FAs.