Can We Prevent Suicide and Self-Harm?

Each year, more than 700,000 people die by suicide. Many more engage in deliberate self-harm. As a result, there have been extensive efforts to predict and prevent both.

Key risk factors for non-fatal deliberate self-harm include female gender, younger age, poor social support, major life events, poverty, being unemployed, being divorced, mental illness, and previous deliberate self-harm.

Key risk factors for suicide include male gender, poor social support, major life events, chronic painful illness, family history of suicide, mental illness, and previous deliberate self-harm. For both deliberate self-harm and suicide, the availability of means is significant (e.g. easy availability of tablets to take overdoses).

Suicide is associated with major depression (long-term risk of suicide: 10-15 percent), bipolar affective disorder (10-20 percent), schizophrenia (10 percent), and alcohol dependence syndrome (15 percent). In addition, individuals who engage in deliberate self-harm have a 30-fold increased risk of completed suicide over the following four years.

Predicting Suicide

Despite these associations from the research, the majority of people with these risk factors will not die by suicide. This is because the increases in risk associated with these risk factors are small and, despite its tragedy and implications, suicide is (from a mathematical viewpoint) a statistically rare event.

As a result, it is impossible to predict suicide at the level of the individual.

There have been many studies of this, and all yield similar results. One classic study followed up almost 5,000 psychiatry inpatients after discharge, using a combination of known risk factors to try to predict suicide in this especially high-risk group. While this study succeeded in predicting 35 out of 67 subsequent suicides, their model also generated over 1,200 “false positives” (i.e. predicted suicide in over 1,200 individuals who did not die by suicide).

That's because suicide is, statistically, a rare event, and rare events are either very difficult or impossible to predict. The risk factors for suicide (male gender, poor social support, etc.) are both very non-specific and very common in the population, so the vast majority of people with these risk factors will not die by suicide.

This is true even for people who have thoughts of suicide, as the proportion of people with suicidal thoughts who go on to complete suicide is less than one in 200. This suggests that simple population screening for suicidal thoughts is unlikely to be either effective or efficient in identifying individuals at risk of suicide.

Overall, then, it is impossible to predict suicide in any individual case.

Bereaved families sometimes believe that there were signs they missed or that health professionals should have predicted the outcome in cases of suicide. Statistically, however, there is no way that anyone can predict suicide in an individual case.

What Can Be Done?

If the risk is impossible to predict accurately at the individual level, what can be done? Plenty.

First, despite the impossibility of prediction in individual cases, careful, realistic clinical assessments and risk explorations are still very useful for guiding treatment and providing support to people who present with a suicidal crisis or mental illness—although it must be remembered that these assessments do not provide a basis for statistical prediction of precisely which individuals will engage in deliberate self-harm or suicide, and which individuals will not.

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In an overall sense, however, good mental health care, good communication with families, and good follow-up likely all help to reduce the risk of suicide.

Good treatment of depression in primary care (by family doctors) is essential, as is the treatment of substance abuse (including alcohol) and management of specific mental disorders by specialist teams.

In emotionally unstable personality disorder, psychological therapies can prove helpful, including adaptions of cognitive-behaviour therapy (CBT) and dialectical-behaviour therapy (DBT). DBT is somewhat similar to CBT and also involves group sessions, building skills such as mindfulness, and developing coping strategies other than deliberate self-harm for dealing with emotional instability. DBT is challenging, but can be highly effective for reducing self-harm in certain conditions, including (but not limited to) emotionally unstable personality disorder.

Public Health

From a public health perspective, public education and measures to limit access to means of self-harm are important and effective.

Regulations governing acetaminophen (paracetamol) sales are an excellent example as they greatly reduce harm resulting from overdose. Placing barriers at known suicide locations (e.g. certain bridges) is another effective method for deterring self-harm and suicide.

Research shows that a great number of people who are deterred or delayed in this fashion will re-consider their suicidal thoughts and very many will not proceed to find other means of self-harm.

Good primary care, good mental health care, and appropriate public health measures are, then, essential for addressing deliberate self-harm and suicide. These measures should be aimed at everyone, not just those with thoughts of deliberate self-harm or suicide. Often, there are no warning signs.

Approaches rooted outside health services are also vital: reducing homelessness, reforming the criminal justice system, and improving access to social care.

This matters to everyone. One in four people will develop a mental illness at some point in life.

There is no “them.” There is only “us.”

If you or someone you love is contemplating suicide, seek help immediately. For help 24/7 contact the National Suicide Prevention Lifeline, 1-800-273-TALK. To find a therapist near you, see the Psychology Today Therapy Directory.

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