Pneumonia causes a significant public health burden in the UK in terms of morbidity and mortality. Historically, the annual incidence of community acquired pneumonia has been reported to be between 5 and 11 per 1000 adult population,1–3 estimated more recently to be between 207 and 233 per 100 000 in England.4 In 2010, influenza and pneumonia were responsible for 4.5% of all male deaths, and 5.8% of all female deaths ranking them 5th and 4th in terms of causes of mortality in men and women respectively in England and Wales.5 With such a huge mortality burden, it is important to identify modifiable risk factors to help decrease the incidence of the disease. The commonest cause of community acquired pneumonia, accounting for over a third of cases, is Streptococcus pneumoniae.6 ,7 S pneumoniae is also an important cause of septicaemia, meningitis, infective exacerbations of chronic obstructive pulmonary disease and bronchiectasis. Vaccination against S pneumoniae is recommended in many countries for high risk groups. In the UK, these groups include all children, all those over 65 years, as well as subjects with chronic medical conditions that are associated with a higher risk of pneumococcal disease including COPD, renal impairment and cardiovascular disease.8

Several factors that are associated with an increased risk of pneumonia and pneumococcal disease, including being underweight, excessive alcohol intake and smoking,8–10 are also commoner in patients with mental illnesses such as psychosis and depression. So, is mental illness also a modifiable and important risk factor for pneumonia and pneumococcal disease? In this issue of the journal, two papers are published suggesting it is. Seminog and Goldacre11 investigated the risk of pneumococcal disease in people with severe mental illness. Using two electronic databases, the English national dataset of linked Hospital Episode Statistics and …