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

Objective: 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).

Methods: 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.

Results: 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.

Conclusion: 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.