“I had no idea how dangerous pain medication would be. I never woke up any day and said, ‘Man, I want to be an addict today.’ And I asked myself, ‘How did you end up here?”

-Mark Edwards for the NOVA documentary “Addiction”

Addiction destroys lives. In far too many cases, addiction also ends them. Overdose is a leading cause of cause of death for people under 50 in America.

Far from a moral failing, as the stigma has long painted it to be, addiction is a complex biological disorder that develops when drugs hijack, rewire, and even reshape the brain. The process is largely tied to the brain’s pleasure hormone, dopamine. Dopamine is naturally released when endorphins, the body’s natural pain relievers, bind to receptor proteins. Dopamine tells the brain, “This experience was good. Repeat it.”

Opioid drugs mimic endorphins. However, they release a tsunami of dopamine up to ten times higher than normal. The brain’s reward pathway is thus flooded with a high unlike anything it’s probably ever experienced.

“Individuals struggling with addiction are actually battling millions of years of evolution because our brains are exquisitely evolved to seek rewards, to seek reinforcement wherever and whenever we can.” says Stanford University’s Dr. Robert Malenka for “Addiction.”

At the turning point, drugs are no longer about reducing original pain or seeking pleasure. Instead, they’re necessary for the agony of withdrawal. The brain and body physically demand more not to relish the high, but to escape the low.

Withdrawal is crippling. When opioids are abruptly paused, stress hormones surge at catastrophic levels. This imbalance leads to the opposite symptoms of opioid use, including shaking, anxiety, pain, and intense dysphoria. The pain is all-consuming — some people describe it as feeling like their bones are being ripped out of their bodies.

As the brain screams for more, the compulsion to get more drugs clouds over logic and rational judgment. There’s physical evidence for this shift. Brain scans show chronic drug use is associated with reduced gray matter in the prefrontal cortex, the brain’s executive control center that governs decision-making. The lower the amount of gray matter, the less someone is able to control their behavior.

Addiction has now taken over. And so the cycle continues.