Antidepressants reduce the odds that a suicidal person will take their own life but increase the risk of a suicide attempt, new research has found.

A Finnish team of researchers found that people at risk of suicide were less likely to go on to die by suicide if they received antidepressant drugs.

However, the research distinguished between suicide attempts and completed suicides and the team, lead by Dr Jari Tiihonen, found that patients were more likely to attempt suicide after receiving antidepressants.

It was observed that patients not taking anti-depressants were more likely to use violent means of suicide, potentially explaining the differing numbers of actual deaths.

Published in the Archives of General Psychiatry, the study used Finnish databases to study 15,390 non-psychotic patients who had been hospitalised after a suicide attempt between 2005 and 2009.

Some of these were then prescribed drugs, taken from one of three classes of antidepressants; tricyclic antidepressants (eg Elavil), selective serotonin reuptake inhibitors (eg Prozac) and serotonergic-noradrenergic antidepressants (eg Effexor).

Among the whole group, 602 took their own life, 7,136 made a suicide attempt that again resulted in hospitalisation and 1,583 died by other causes.

The risk of completed suicide was nine per cent lower among those patients receiving antidepressant drugs. However, these patients were 36 per cent more likely to attempt to take their own life than those not taking antidepressants.

The increased risk of attempted suicide was most marked among patients aged ten to 19-years-old.

In addition, mortality from cardiovascular disease was lowered among the drug-users, particularly those prescribed Prozac-like drugs.

The research concluded: “Among suicidal subjects who had ever used antidepressants, the current use of any antidepressant was associated with a markedly increased risk of attempted suicide and, at the same time, with a markedly decreased risk of completed suicide and death.”

The report follows prolonged discussion about the impact of antidepressant drugs on suicidal behaviour, with concerns already sounded that children and adolescents are more likely to attempt suicide after receiving treatment certain antidepressant drugs.