Depression is common and disabling. The estimated point prevalence for major depression among 16 to 65 year olds in the United Kingdom (UK) is 21/1000 (males 17, females 25). Mixed anxiety and depression is prevalent in a further 10 percent of adult patients attending general practice (National Institute of Health and Clinical Excellence [NICE] Depression guideline, 2004). It contributes 12 percent of the total burden of non-fatal global disease and by 2020, looks set to be second after cardiovascular disease in terms of the world's disabling diseases (Murray CJL and Lopez AD, 1996). Major depressive disorder is increasingly seen as chronic and relapsing, resulting in high levels of personal disability, lost quality of life for patients, their family and carers, multiple morbidity, suicide, higher levels of service use and many associated economic costs. In 2000, 109.7 million lost working days and 2,615 deaths were attributable to depression. The total annual cost of adult depression in England has been estimated at over 9 billion pounds, of which 370 million pounds represents direct treatment costs.
This measure is one of two Depression measures.
There is now evidence to suggest that the use of questionnaire measures of the severity of depression does help rationalise antidepressant prescribing. An audit was carried out of the use of the Hospital Anxiety and Depression scale depression sub-scale (HAD-D) by GPs in seven practices in Southampton City Primary Care Trust between December 2005 and April 2006. The participating General Practitioners (GPs) agreed to use the HAD-D with all patients they were considering for possible treatment for depression, anticipating this indicator in the Quality and Outcomes Framework (QOF) by six months. The scheme was rewarded through the Trust's prescribing audit incentive scheme. The likelihood of being prescribed an antidepressant increased significantly with severity on the HAD-D (P < 0.0001) (Kendrick, British Journal of General Practice 2006). Overall, of 134 new courses of antidepressants recorded in this study, only 18 (13.4%) were for patients with scores below the threshold for possible major depressive disorder, indicating good targeting of antidepressant treatment within this group, in line with guidelines. This represented an improvement when compared with a previous observational study of GP treatment of depression in Southampton, which showed that antidepressants were poorly targeted to those with more severe depression, due to the inaccuracy of practitioner clinical assessment of severity when compared to the HAD-D (Kendrick et al., British Journal of General Practice 2005). Measuring severity therefore does seem to improve the targeting of GP antidepressant treatment, which is the implicit aim of this quality indicator.
Assessment of severity is essential to decide on appropriate interventions and improve the quality of care.
A measure of severity at the outset of treatment enables a discussion with the patient about relevant treatment interventions and options, guided by the stepped care model of depression described in NICE guidance. The guidance states, for example, that antidepressants are not recommended for the initial treatment of mild depression (Grade C evidence) but should be routinely considered for all patients with moderate or severe depression (Grade B evidence). The British Association of Psychopharmacology Guidelines state that antidepressants are a first-line treatment for major depression irrespective of environmental factors (Grade A evidence) and that antidepressants are not indicated for acute milder depressions (Grade B evidence) (Anderson et al., Journal of Psychopharmacology 2000).
The three suggested severity measures validated for use in a primary care setting are the Patient Health Questionnaire (PHQ-9), the Beck Depression Inventory Second Edition (BDI-II) and the Hospital Anxiety and Depression Scale (HADS). It is advisable for a practice to choose one of these three measures and become familiar with its questions and scoring systems. Refer to the original measure documentation for further details regarding each of these three assessment tools.
