Depression, anxiety and their relationship with chronic diseases: a review of the epidemiology, risk and treatment evidence.

OBJECTIVE: To review the evidence for an association between depression and anxiety and the National Health Priority Area conditions -- heart disease, stroke, diabetes mellitus, asthma, cancer, arthritis and osteoporosis -- and for the effectiveness of treatments for depression and anxiety in these settings. DATA SOURCES: Systematic literature search of systematic reviews, meta-analyses and evidence-based clinical practice guidelines published between 1995 and 2007, inclusive. DATA EXTRACTION: Each review was examined and summarised by two people before compilation. DATA SYNTHESIS: Depression is more common in all disease groups than in the general population; anxiety is more common in people with heart disease, stroke and cancer than in the general population. Heterogeneity of studies makes determination of risk and the direction of causal relationships difficult to determine, but there is consistent evidence that depression is a risk factor for heart disease, stroke and diabetes mellitus. Antidepressants appear to be effective for treating depression and/or anxiety in patients with heart disease, stroke, cancer and arthritis, although the number of studies in this area is small. A range of psychological and behavioural treatments are also effective in improving mood in patients with cancer and arthritis but, again, the number of studies is small.
CONCLUSION: The evidence for the association of physical illness and depression and anxiety, and their effects on outcome, is very strong. Further research to establish the effectiveness of interventions is required. Despite the limits of current research, policy and practice still lags significantly behind best evidence-based practice. Models of integrated care need to be developed and trialled.