The Devastating Effects Heroin Has on the Body and Mind

Heroin's most vicious attack is on the brain.

"For most, addiction is a lifelong disease," said O'Brien, a professor of psychiatry at the Penn Medicine Neuroscience Center.

Heroin's most vicious attack is on the brain. The powerful narcotic activates the brain's natural opioid receptors that regulate pain, reward and pleasure and highjacks their pathways. That euphoric high leads to physical changes in brain molecules, Dr. Joshua Lee of the NYU Langone Medical Center said.

O'Brien says heroin also "creates memories." For recovering addicts, just smelling or seeing heroin can trigger intense memories with uncontrollable cravings.

And there is always the chance of a deadly overdose. "On too much heroin, breathing slows down or stops completely," said Lee.

Users also report feeling intense aches, muscle pain, restless leg, bone pain and skin crawling sensations during withdrawal. On heroin, pain is suppressed, but afterward the pain control system becomes hyper-sensitive, amplifying every discomfort, O'Brien added.

Probably the greatest danger of heroin, say experts, is physical dependence. "While a typical dose doesn’t directly destroy your brain, overall the addiction can destroy your life," said Lee.