Numerous studies have found that persons with mental disorders are at significantly higher risk for suicide than the general population. In ‘psychological autopsy’ studies (Table 15.1) the prevalence for current mental disorders among suicide victims has been as high as 81 to 100%. The heightened suicide risk has been associated with many types of mental disorder, most often with affective disorders, substance abuse and schizophrenic disorders (Miles, 1977; Black et al., 1985; Harris and Barraclough, 1997). Suicide is the most common cause of premature death in schizophrenia: 28% of the excess mortality in schizophrenia, and 11-38% of all deaths in schizophrenia are attributable to suicide (Leff et al., 1992; Brown, 1997; Baxter and Appleby, 1999).

Methodological aspects of suicide research

Definition of suicide

As with all human behaviour, suicide is complex and multifaceted in nature. From the research point of view, studying suicide is fraught with many methodological problems. There is no single, unanimously accepted definition of suicide. Definitions often include three components: the death occurs as a result of an injury, which is both self-inflicted and intentionally inflicted. The least ambiguous factor is that the outcome of the injury is death. It has been suggested that suicidal intent may represent the varying degree of consciousness and determination to die in suicide (Stengel, 1960; O'Carroll et al., 1996).