TOXICOLGY results have found that the young man who carried out a murder-suicide six months ago had a "potentially fatal dosage" of antidepressants in his system when he carried out his attack.

Shane Clancy, from Dalkey in south Dublin, stabbed Sebastian Creane at his home in Bray in Co Wicklow, before turning the knife on himself on 16 August last. The Trinity College Dublin student also stabbed his former girlfriend Jennifer Hannigan and Creane's older brother Dylan in the attack. Both have recovered from their injuries.

The 22-year-old's family have spoken publicly about their belief that antidepressants drove him to carry out his fatal knife attack. One week before the incident, he overdosed on antidepressants in a suicide attempt and was later given another prescription for more anti-depressants.

Wicklow east coroner Cathal Louth will hold an inquest into Shane Clancy's death on 15 April, where medical evidence relating to the toxicology results will be heard. Clancy had been prescribed a brand of the antidepressant citalopram but had not been adhering to the recommended dosage. No alcohol or any other substance was found in Clancy's system aside from the "extremely high dosage of antidepressants that was potentially fatal", according to a garda source.

Sebastian Creane's inquest will be held at a separate date. Gardaí and the Wicklow east coroner received the toxicology results in recent weeks and have informed the family. The Trinity student's family have said they are anxious to explore whether pills influenced his behaviour. If permitted by the coroner, expert medical witnesses enlisted by the family could be called to give evidence about the impact anti-depressants can have on a patient's behaviour.

Clancy started taking anti-depressant medication a week before the murder-suicide and had told friends that he did not like the way the drugs "made him feel". Medical practitioners have pointed out that patients taking antidepressants should not stop taking their medication because of negative publicity surrounding this case.

The 22-year-old became depressed following the break-up of his relationship with Jennifer Hannigan, who began dating her fellow design student Sebastian Creane. On the night of the attack, Clancy met Creane out socialising and then dropped him to his home in Cuala Grove, Bray. He then drove to a 24-hour shop and bought knives and returned to the Creane family home.

After fatally stabbing Creane, he stabbed his ex-girlfriend and Dylan Creane before turning the knife on himself.