US medicines regulators are reviewing anti-depressants again to determine whether the widely used drugs can increase the risk of suicidal tendencies in adults.

The Food and Drug Administration is asking makers of all marketed anti-depressants to provide comprehensive clinical trials data. It expects the review to take about a year to complete. The FDA will analyse the trials in the same manner it reviewed data on anti-depressant use in children, looking for instances of suicidal behaviours.