It has long been known that people with schizophrenia have higher mortality rates from a number of causes, particularly suicide, than the general population. Higher than expected rates of comorbid substance abuse and violent behaviour have also been noted. The chapters in this section examine the epidemiological evidence for these associations, which have important implications for treatment and management.

Mortensen in Chapter 14 finds strong evidence that individuals with schizophrenia have elevated mortality rates from natural causes, thus leading to the expectation that individuals with schizophrenia have higher rates of a range of physical disorders. However, the epidemiological investigations of this issue have not been systematic. Investigators have tended to focus on certain diseases such as rheumatoid arthritis, diabetes mellitus or multiple sclerosis among schizophrenic patients in an effort to support an autoimmune aetiological hypothesis. Mortensen emphasizes the logistic difficulties inherent in such enterprises: ‘the study of one relatively uncommon disorder among patients with another relatively uncommon disorder requires very large study populations to be followed up for a long time’. Some studies have found a reduced rate of cancer in schizophrenia, while others have found higher rates. Few studies have examined rates and risk factors for cardiovascular disease, although this is one of the major causes of the excess mortality.