How / why does the body become physiologically dependent on a substance?
What happens to our bodies to create a physical substance dependence? Like the only way to prevent someone in severe withdrawal from dying is to give them more of the substance they are addicted to? It seems obvious to me that dopamine/serotonin etc have their effects in psychological dependence but shouldn’t our bodies react more positively to not being regularly hit with what is basically a poison/s?
In: Biology
My take: body is a incredibly precise machine that produces many substances for many reasons (eg alcohol) in small quantities. When you introduce an outside source of such substance, body detects it and stops producing it. Moreover, since your intake of such substance is much higher than it would be naturally, body adapts to increasing quantities of it. When you try to drop it, body cant perform certain functions since it doesn’t produce such substance anymore and it adapted to a much higher quantity of it anyway.
Let’s say your body and brain is a factory.
This factory runs well and efficient, usually. Well, randomly you get a massive order for parts left and right, you order more truckloads of materials and start pumping stuff out at a way faster rate. Your factory is running overtime. But then, suddenly, the person cancels their order at the last second. Now you have tons of materials, and tons of stuff already made, and the entire factory goes out of wack.
Alcohol is a good example. It’s a nervous system suppressant, so your body has to compensate for this, especially if you continuously get drunk. Your brain compensates more and more, it’s pushing against a metaphoric wall, and the more you drink the higher tolerance you get, requiring more and more each time, making your brain push harder and harder against that wall. Cutting cold turkey is like that wall disappearing in the blink of an eye. All that force from pushing sends you flying forward, falling on your face.
Your body gets used to things. Your brain compensates for changes over time. It’s trying to run properly, so it starts working harder. But if you suddenly take away the reason for the brain working so hard, it ‘floods’ your brain. There is nothing to compensate anymore.
I guess another way to think about it is like a dam in a river. The dam slows the flow, ensuring everything is smooth and controlled. This dam has been there for a long time, slowing the flow of water for years, erosion making a distinct shallow ‘canal’ on the other side of the dam. Well, let’s say that dam catastrophically fails. Hundred thousand gallons of water suddenly slams down, it instantly floods everything. The canal is only so wide and deep, it’s been used for only a small amount of water, but now the dam is broken and all hell breaks loose.
Let’s take alcohol as an example. Alcohol imitates a chemical that the nerves in your brain use, called GABA. What GABA does, basically, is tell nerves to chill out. (It’s an “inhibitory neurotransmitter”; it tells nerve cells to fire less.)
If you’re a very heavy drinker and have lots of alcohol in your system all the time, your nerves learn to pay less attention to GABA — because the alcohol is doing GABA’s job and more. You don’t need to tell your nerves to chill out, because they’re already drunk.
But then if you *stop* taking alcohol, now your nerves run too hot! The job that GABA is supposed to do — get your nerves to chill out — *isn’t getting done.* As a result, your nerves fire too much, making you shake, sweat, hallucinate, and even have seizures. This is *delirium tremens* (“the DTs”) and it’s one of the worst symptoms of acute withdrawal from high alcohol intake.
So physical dependence on alcohol is due to your brain adjusting to having alcohol all the time, and becoming less able to chill itself out *without* alcohol.
What begins as behavioral use, experimental trial, deceives you eventually into a denial of your ability to control use. Meanwhile your repetition of use has already turned into a physical need without realization. That’s addiction.
Someone else can give you medical terms, but it’s easier than you think to change aspects of your body internally to become dangerously dependent.
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