A drug and alcohol expert has said it is unlikely that the death of a Central Coast teenager was caused by an LSD overdose.
Nick Mitchell, 15 suffered heart and respiratory problems after taking the drug with a friend, also 15, on Saturday.
But Drug and Alcohol Research and Training Australia director Paul Dillon said it is more likely that the teen died from an incident relating to taking the hallucinogen.
Mr Dillon said there has been no documentation of a human death from an LSD overdose.
"It is unlikely that the teen died from an LSD overdose as the drug does not cause respiratory failure but it does alter the perception of the user," he said.
"The symptoms of taking the drug cause the person to go into a psychosis and hallucinate which may result in them walking in front of a car or getting into some type of an accident."
Mr Dillon said until the results of the toxicology are released, he will not speculate the cause of the teenager's death.
"Until we receive all the information, the best possible message we can get across is to provide the right information to the public," he said.
"There is an increase in usage of the drug especially among young people and the message is to warn them about the effects."
According to the police, Nick was found unconscious on his bedroom floor by his 11-year-old brother at their home in Tascott on Saturday.
The drug caused his friend to become psychotic and run naked into traffic.
He is in hospital with serious injuries after being hit by a car.
The two teenagers had been spending the day hanging out in Nick's granny flat-style bedroom and neighbours reported seeing them playing in the backyard pool showing no signs of anything abnormal.
Around 8.30pm AEDT Nick's younger brother made a frantic call to his mother saying he had found the teen slumped on the floor not breathing.
Police said officers later found the bedroom had been "smashed up".
A neighbour performed CPR on Nick as paramedics rushed over.
But the ambulance was stopped just around the corner from the Mitchell's house when it came across Nick's friend who had been struck by a car.
Another ambulance was sent out for Nick but he was pronounced dead on arrival at Gosford Hospital.
Detectives said the incident came after numerous other reports of people suffering serious side effects from LSD and there were fears a toxic batch of the drug could be circulating.
"LSD, if that's what it was, is an insidious drug. It's got a smiley face on it and looks harmless, but it kills," Detective Superintendent Nick Bingham told The Daily Telegraph.
Brazilian student Roberto Laudisio Curti died in Sydney's CBD in March after he took LSD, fell into a psychotic state and was tasered by police after a struggle.
Sources: The Daily Telegraph, Paul Dillon
Author: Bernadette Chua and Alys Francis. Approving editor: Nick Pearson