The Science of Addiction and How it Hijacks the Brain
- James Crystal
- Apr 9
- 4 min read
"EVERYTHING FELT MUNDANE AND MEANINGLESS"
I’ve lived it.
Addiction isn’t just about making bad choices. It’s not about weak willpower or a lack of self-control. At it's core, it's much deeper than that - something happening inside the brain.
For years, heroin, opiates and cocaine controlled my existence. I felt trapped in an unforgiving cycle I couldn’t escape, like my own brain was working against me. Now, as a public speaker delivering drug prevention talks in schools and colleges, I help young people understand addiction from both a personal and scientific perspective.
Because when you understand how addiction hijacks the brain, you see just how dangerous it really is.
Dopamine: The Brain’s Reward System
Your brain is designed to keep you alive. It rewards you with pleasure when you do things that help you survive, like eating, exercising, or spending time with loved ones. It does this by releasing a chemical called dopamine, which makes you feel good and encourages you to repeat those behaviors.
But drugs override this system.
When someone takes drugs such as cocaine or heroin, the brain is flooded with dopamine, far more than it would ever naturally produce. This creates an intense high, reinforcing the idea that taking the drug is a good thing. The problem? Firstly, it feels so good! Secondly, the brain notices this unnatural surge and starts adjusting. It reduces its own dopamine production, which weakens our dopamine receptors.
This is why people struggling with addiction start losing interest in everyday activities. The things that used to bring joy - hobbies, sports, friendships - feel dull or meaningless. The only way to feel anything? More drugs.
And that’s how the cycle begins.
I remember reaching a point where nothing in life mattered except blasting that bong or that pipe. When I wasn’t using, I felt completely empty. That’s not just a psychological craving - it’s a physical change in the brain.
How Addiction Changes the Brain
As addiction develops, the brain goes through three major changes:
1. Tolerance and Dependence
The more someone uses, the more their brain adjusts, and the less effect the drug has. This means they need more of the drug to get the same high. Eventually, they’re not even using to feel good anymore - they’re using just to feel “normal.” Hence why it's called dependence.
2. Weakened Decision-Making (The Prefrontal Cortex)
The prefrontal cortex - the part of the brain responsible for decision-making, impulse control, and thinking ahead - gets weaker. This is why addiction leads to risky, uncharacteristic behavior. It’s why people do things they swore they'd never do. The concept of "free will" essentially dissipates as the addiction takes hold. It’s why I did things I never imagined doing. My addictions had taken over my ability to think rationally.
3. Memory, Triggers, and Cravings
The brain starts associating certain people, places, or emotions with drug use. This is why cravings can emerge out of nowhere, even after someone has been clean for years. A traumatic memory, a name, or a geographical area can bring back a powerful urge to use.
These changes make quitting incredibly difficult. But far from impossible.
Why Young People Are at Higher Risk
Many young people don't realise their brain isn’t fully developed until around age 25. That means if you start using drugs in your teenage years, your brain literally builds around them.
This makes young people far more vulnerable to addiction. In fact, studies show 90% of addicts started using psychoactive substances in their teen years. Addiction takes root in teenage years.
Check out these statistics:
Cannabis Use: In England, 17.6% of young people (aged 16-24) used cannabis in the last year. It remains the most commonly used drug among young people.
Frequent Drug Use: 4.7% of young people (16-24) are classified as frequent drug users, meaning they use drugs more than once a month.
Cocaine, Ketamine & Ecstasy: Among young people in drug treatment, 9% reported problems with ecstasy, 8% with ketamine, and 8% with cocaine.(ONS, 2023, Gov.uk, 2024)
But these numbers aren’t just statistics - they represent real people, real lives, and real futures - being shaped by addiction.
The Good News: The Brain Can Heal
Here’s what I want every person to know: addiction isn’t a life sentence. It can kill you, yes. But if you're still alive, you still have a chance to change.
Yes, drugs change the brain, but the brain is also remarkably capable of healing.
When someone stops using and starts engaging in healthy behaviors, the brain begins to rewire itself. Over time, natural dopamine production returns, and joy from everyday activities does come back.
I know because I’ve lived it.
When I first got clean, I struggled. I had to relearn how to enjoy life without drugs.
At first, everything felt mundane and meaningless. But slowly, through consistency, connection, and purpose, my brain healed.
It's healed, yes. I'm clean, yes. But I'm still an addict, and the same cycles still play out. I'm just more in control of it now.
This is why I stand in front of young people sharing my story. I want them to understand the risks before they ever start. I want to prevent the first day rather than the worst day. And if they've already started?
I want them to know that change is possible because the person standing in front of them has done it.
Final Thoughts: You Have a Choice
Addiction is not a switch you can flip. It's not an active choice. It’s a slow, creeping process that takes control of us, often before we even recognise it as a problem.
That’s why it can be so hard to break free from addiction.
If you’re struggling, or if someone you love is caught in addiction, please know this: this is not the end of the road.
If you're reading this, it's not too late to make a change.
Reach out. Talk to someone. You are not alone.
📩 Get in touch today to learn more about my talks and how I can help your school or organization.
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