Police have identified two types of pills that are believed to have led to two deaths at Toronto's VELD Music Festival over the long weekend, but they still aren't sure what the pills actually contain.

The pills are essentially a form of methylenedioxymethamphetamin (MDMA) or ecstasy, an addictions specialist said. But pills are reproduced by dealers to get more prolonged effects, so it can be difficult to identify the elements mixed to create the pills, he said.

In an interview with CTV's Canada AM on Wednesday, the president of Addiction Canada John Haines said that the pills are manufactured to get users hooked.

"Potency is what will bring them back to say, 'I want that pill again,'" Haines said.

Dealers are breaking up existing pills, adding substances and pressing the powder into new pills, adding their own stamps, he said. The drugs are then mass produced and sold at events.

Haines said that what makes the drugs fatal is what's added to the drugs to increase potency, which can be anything from cocaine to arsenic.

MDMA prevents the body from regulating its own temperature, Haines said. Heart rate and blood pressure increase and the body overheats. The drugs can lead to cardiac arrest, seizures and strokes, he said.

Haines’ son, who attended the VELD Music Festival, told him he thinks his friends were offered the same drugs that led to the deaths of Willard Amurao, 22, and Annie Truong-Le, 20.

On Tuesday, police zeroed in on two different pills that may be linked to two deaths at the festival: a small, brown pill and a small, clear capsule filled with a white substance. The party drugs were singled out after police put out a public appeal to festival-goers to turn over any substances that were purchased at VELD.

Anyone who may have bought the substance is being warned not to take it, and to turn it over to police so they can analyze the drug.

Culture of party drugs

Addictions expert John Streukens said that peer pressure is often to blame for the connection between rave culture and party drugs, which groups will take to try to enhance their experience of the event.

Streukens told CTV's Canada AM that young adults haven't yet developed the thought process that encourages older adults not to take risks. He said that youth don't always think about consequences before acting.

Streukens advised parents to be aware of their children's peer groups and watch for major changes in their behaviour and grades. He said that parents should start the conversation early, with children as young as 6 years old, to encourage awareness of the dangers of drugs.