The drug, lithium, reduces the risk of suicide in people with mood disorders and may reduce the risk of self-harm, a new study indicates.

There are two main types of mood disorders - unipolar and bipolar disorder. Unipolar is often referred to as clinical depression, while bipolar is also known as manic depression.

With bipolar disorder, people experience sustained high moods (mania), followed by period of sustained low moods. Manic episodes can include feelings of elation, rushed speech, a reduced need for sleep and hyperactivity. Lithium is currently used to treat the manic episodes of bipolar disorder.

According to UK and Italian scientists, people with mood disorders are 30 times more likely to die by suicide compared with the general population. While treatment with certain drugs, such as lithium, can help control moods, their role in the prevention of suicide has, until now, been unclear.

The scientists therefore set out to investigate whether lithium can help to prevent suicide and self-harm in people with both unipolar and bipolar disorder.

They analysed the results of 48 trials involving over 6,600 people. The trials looked at the effects of lithium, other drugs and placebo in the long-term treatment of mood disorders.

The scientists found lithium ‘seems to reduce the risk of death and suicide by more than 60% compared with placebo'. They believe these results ‘reinforce lithium as an effective agent to reduce the risk of suicide in people with mood disorders'.

The drug appears to work ‘by reducing relapse of mood disorder'. There is also some evidence that it ‘decreases aggression and possibly impulsivity, which might be another mechanism mediating the anti-suicidal effect'.

When it came to deliberate self-harm, the findings were not as clear, but they suggested that the drug may play a small role in reducing the risk.

The scientists from Oxford and Verona acknowledged that the drug has a number of side-effects, but they urged doctors to ‘take a balanced view of the likely benefits and harm of lithium in the individual patient'.

"Understanding the mechanism by which lithium acts to decrease suicidal behaviour could lead to a better understanding of the neurobiology of suicide," they added.

Details of these findings are published in the British Medical Journal.

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