OBJECTIVE: To determine whether an intervention using postcards (postcards from the EDge project) reduces repetitions of hospital treated deliberate self-poisoning.

DESIGN: Randomised controlled trial.

SETTING: Regional referral service for general hospital treated deliberate self-poisoning in Newcastle, Australia.

PARTICIPANTS: 772 patients aged over 16 years with deliberate self-poisoning.

INTERVENTION: Non-obligatory intervention using eight postcards over 12 months along with standard treatment compared with standard treatment alone.

MAIN OUTCOME MEASURES: Proportion of patients with one or more repeat episodes of deliberate self poisoning and the number of repeat episodes for deliberate self poisoning per person in 12 months.

RESULTS: The proportion of repeaters with deliberate self poisoning in the intervention group did not differ significantly from that in the control group (57/378, 15.1%, 95% confidence interval 11.5% to 18.7% v 68/394, 17.3%, 13.5% to 21.0%: difference between groups -2%, -7% to 3%). In unadjusted analysis the number of repetitions were significantly reduced (incidence risk ratio 0.55, 0.35 to 0.87).

CONCLUSION: A postcard intervention reduced repetitions of deliberate self-poisoning, although it did not significantly reduce the proportion of individual repeaters