A mixed bag of studies reported in the British Medical Journal (February 19) looks certain to fuel the ongoing controversy about the safety of the selective serotonin reuptake inhibitor class of antidepressant drugs, which have been linked to suicide and self-harm.

The US Food and Drug Administration reviewed the issue in the early 1990s, when a panel of experts concluded that there was not enough evidence to link the SSRIs to increased suicide risk. But since then regulators have issued warnings that the drugs can raise the risk of suicidal thinking in a small number of children and adolescents [[18/10/04b]], [[06/12/04a]].

The newly published BMJ studies appear to agree that the risk of suicide is no greater with SSRIs than with the older tricyclic class of antidepressants, but the greatest source of controversy is likely to come from the suggestion that an elevated risk of suicide is seen in adults as well as those aged under 18.

One of the studies – a meta-analysis of 702 randomised trials – found that depressed people on SSRIs were more likely to attempt suicide than those on placebo or other drug treatments, although the chances of completing the act did not increase. This study also found no difference between the SSRIs and tricyclics in suicide risk. However, a second analysis of data from 477 trials submitted to the UK Medicines and Healthcare products Regulatory Agency by drug companies found no increased risk with SSRIs compared to placebo.

Meanwhile, a third study specifically comparing the SSRIs and tricyclics, and looked at the risk of suicide and non-fatal self-harm in more than 146,000 patients prescribed SSRIs or tricyclics for the first time. Again, there was no difference between the two groups in the risk of suicide, although it did find some evidence of an association between SSRIs and self-harm in people aged 18 or younger.