How The Reward System Breaks
There are two ways your reward system can breaks down. First, it can physically break from damage to the component parts. This is usually by disease (stroke, Parkinson’s, Huntington’s or Alzheimer’s) or by brain trauma (car crash, boxing or football).
Second, it can be hijacked by drugs. Any drug that is addictive impacts dopamine. If it’s addictive, it’s dopamine.
Drugs overwhelm your brain with dopamine. Think of your best orgasm (usually the highest natural high people have). One dose of cocaine feels 10x higher and more intense.
Cocaine leaves more dopamine in the synapses by disrupting its reuptake (recycling). Instead of going back into the cell for reuse, dopamine is left out in the synapse. Consequently, with so much dopamine out there, it takes very little more to trigger a neural connection.
The body tries to adjust to the new amount of dopamine present. As the tolerance increases, users take more cocaine to compensate. Eventually, they are taking very high levels of cocaine just to get as high as they used to.
Actually, you can never get as high as you used to (for a given dose). The first time you have a drug (or experience) is always the biggest impact it will ever have. Like your first love, first job and first car, your first hit of cocaine, heroin, or caffeine is always the largest.
Cocaine doesn’t stop there. It increases the deltaFosB levels with no tolerance ceiling. As you know (as least now), deltaFosB is a protein that changes your genetic transcription process. It elevates BDNF (brain-derived neurotrophic factor), which increases the number and complexity of dendrites (input receivers) in the brain, particularly the nucleus accumbens. This means that the brain is now more ready to receive cocaine-generated stimuli. Drugs change your brain.
Drugs increase your sensitivity to positive reinforcement. Being rewarded impacts you more than it did before. But the only reward that matters to you now is cocaine.
Remember your reward system is designed to regulate natural rewards, such as food, sex and exercise. We use this reward hierarchy to inform ourselves of what we should do. A cocaine user is no longer getting good feedback from the reward system.
In addition to increasing sensitivity to positive reinforcement, drugs decrease your sensitivity to aversion. Things that you found punishing before no longer bother you. You are less afraid of getting caught, less concerned about bad things that can happen to your or others.
On drugs, the brain also produces more compulsive reward-seeking behavior. The habit portion of the drug habit increases. Have you ever tried to stop drinking coffee, only to find yourself standing in line at Starbucks? Similarly, alcoholics find themselves drinking.
Drugs block receptors from receiving stimulation, bind them too long or prevent them from binding at all.
The also fool the transporters that recycle the neurotransmitters. Amphetamines are synthesized to imitate dopamine. They are so dopamine-like that the transporters prefer them to the real thing, and reuptake them instead.
How long does it take to get addicted? Once+. For some people, once is enough. For others, it takes repeated does to become dependent. It’s all about body chemistry. And there is no way of knowing how many doses it will take you.
Drugs are well-known for their cravings. This is another result of the reward system. Activity in the prefrontal cortex correlates with these cravings. Cravings are powerful urge to have more. Think of the cravings some women have during pregnancy and amplify them. Cravings for some drugs can last for months after disuse.
Inhalants not only impact dopamine but also deprive the brain of oxygen. The brain’s multiple components work together. When one region shuts down, it tries to find other ways of coping but isn’t always successful. If the brain is deprived of oxygen for even a relatively short period of time, it cannot always make reconnections with itself.
Many drugs are toxic in and of themselves. Alcohol is metabolized in a two-stage process. The first stage converts toxic alcohol into an even more toxic state. This phase results in headaches, rashes, vomiting and other symptoms. But the body is doing its own version of finding a common denominator.
Remember your elementary school mathematics? To add or multiply fractions, you often have to find a common denominator. Something the items have in common. With alcohol, the body is trying to find something it can easily disassemble. First, it converts alcohol into a complex substance. Second, it disassembles it into what is essentially vinegar.
Hangovers are the result of finding a common denominator.
Stimulants increase the frequency of neural firing. Opioids slow them down. Hallucinogenics can do both and also change the timing. LSD impacts the brain by changing the firing rhythm. It makes neurons fire out of sequence.
Next we’ll look at how to fix a broken reward system.