Suicide: risk factors

The risk stratification of psychiatric patients into 'high', 'medium' or 'low risk' is common in clinical practice. Questions based on a patient's suicide risk are therefore often seen. However, it should be noted that there is a paucity of evidence addressing the positive predictive value of individual risk factors. An interesting review in the BMJ (BMJ 2017;359:j4627) concluded that 'there is no evidence that these assessments can usefully guide decision making' and noted that 50% of suicides occur in patients deemed 'low risk'.

Whilst the evidence base is relatively weak, there are a number of factors shown to be associated with an increased risk of suicide

• male sex (hazard ratio (HR) approximately 2.0)
• history of deliberate self-harm (HR 1.7)
• alcohol or drug misuse (HR 1.6)
• history of mental illness
  • depression
  • schizophrenia: NICE estimates that 10% of people with schizophrenia will complete suicide
• history of chronic disease
• advancing age
• unemployment or social isolation/living alone
• being unmarried, divorced or widowed

If a patient has actually attempted suicide, there are a number of factors associated with an increased risk of completed suicide at a future date:

• efforts to avoid discovery
• planning
• leaving a written note
• final acts such as sorting out finances
• violent method

Protective factors

There are, of course, factors which reduce the risk of a patient committing suicide. These include

• family support