Anatomy of MDMA: What it really does to your body
It's the colourful, candy-like drug seducing festivalgoers with its promise of a euphoric high that users say makes them feel at one with the universe and dance for hours.
There is very little offence in its appearance but it is a coin flip to whether it will lead to the best or worst night of the taker's life.
University of Sydney clinical professor Andrew Dawson said MDMA - colloquially known as ecstasy or "Molly" - is a type of amphetamine that increases the release of certain brain chemicals, which make people feel happy.
"But those chemicals also interfere with the thermostat of the brain which regulates body temperature as well as causing body cells to generate more heat," Professor Dawson said.
"When people take ecstasy and take multiple doses and push the dose up, that regulation of the thermostat gets much worse and heat production increases."
The University of Sydney Faculty of Science's Dr Samuel Banister said MDMA was not inherently dangerous but can be in the wrong circumstance.
"MDMA is a small molecule structurally related to amphetamine so if people use MDMA the feelings that are reported commonly are increased empathy, desire to dance, increased warmth and some of these stimulating effects that are common to amphetamines," Dr Banister said.
But he added it was hard to predict exactly how an individual would respond to any drug, including MDMA, because there were so many variable factors.
These range from a person's diet and their general physical health to what activities they are undertaking that day and whether they have taken any other substances.
"Poly drug-use is sometimes an issue if you've taken it with other substances they can sometimes interact by several well-known mechanisms," Dr Banister said.
"Alcohol generally doesn't mix with anything … it's an inherently pretty toxic substance itself and it doesn't play well with other drugs."
The effects of MDMA are usually felt about 20 minutes to an hour after taken and last for about six hours, according to Australia's Alcohol and Drug Foundation.
But there is no hard and fast rule because some pills sold as ecstasy may only have contained a small amount of MDMA or none at all.
Signs and symptoms of a potential overdose can affect any part of the body, and could include headaches, blurred vision, restlessness, anxiety, paranoia and either a clenched jaw or grinding teeth.
An elevated body temperature, chills or excessive sweating are also symptoms of a potential overdose, while some users will also experience abdominal cramping, nausea and vomiting.
An overdose could also lead to seizures, a loss of consciousness, confusion and other changes in mental state as well as an irregular, rapid heart rate, as well as symptoms of chest pains.
MDMA is often mixed or "cut" with other drugs or fillers to make it go further, meaning the strength will vary from batch to batch and impact the high a person experiences.
This also makes it difficult to know whether MDMA itself is addictive and research has not yet provided a definitive answer.
Some users have reported symptoms of addiction including continued use despite negative consequences, withdrawal and craving.
While it is generally only known as a party drug, Dr Banister said MDMA is being used in clinical trials for the treatment of post-traumatic stress disorder (PTSD).
"The drug is manufactured to a very high purity, it's administered by clinicians and under supervision from clinicians so clearly it can't be that dangerous intrinsically or it wouldn't be in a trial at all," Dr Banister said.
"But of course, it can have very serious effects in cases of overdose."
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