"He could have been having a first episode psychotic break that was made worse or triggered by ecstasy," according to Dr. Cindy Kuhn, a neuropharmacologist at the Duke University Medical Center.
Most people assume ecstasy causes euphoria, explained Kuhn. Although that is true in small doses, she said, larger doses -- such as the three pills Hadley allegedly took -- can produce high blood pressure and increased anxiety.
"You'd expect somebody to maybe be very activated -- running around -- more aroused and alert," Kuhn said.
When police arrived early Sunday morning in response to the tip they received that Hadley's parents had been murdered, Hadley appeared "nervous, frantic and very talkative," according to the affidavit.
Hadley's age, 17, is a "prime age to go crazy," Holland said. In the late teens and early 20s the brain is very vulnerable, she explained. That's typically when people develop schizophrenia or manic depression, she said.
In patients with schizophrenia, for example, a drug like ecstasy can trigger an episode, Kuhn said. It's unknown if Hadley suffered from psychological illness.
Port Saint Lucie police spokesman Tom Nichols could not disclose if investigators found drugs in the Hadley home.