Why one drink leads to another: the brain's brake and gas

In the TED-Ed lesson How does alcohol make you drunk? (April 2020), written by Bucknell University neuroscientist Judy Grisel and narrated by Bethany Cutmore-Scott, a drink is followed from the stomach to the liver and then the brain. The lesson has been viewed more than ten million times on ted.com. Its central picture, from that lesson, is a car:

"Alcohol turns up the brain's primary brake, the neurotransmitter GABA, and turns down its primary gas"

From the TED-Ed lesson written by Judy Grisel, 2020

The idea in plain words

With the brake pressed and the gas eased, nerve cells pass fewer signals. That's why a drink or two feels relaxing and more makes you sleepy. The lesson adds two more effects. Alcohol prompts a squirt of dopamine in a part of the brain tied to motivation, and it releases endorphins, which calm you down. Together they make the lift of the first drink.

The brake in her picture is about nerve signals. It doesn't mean your own brakes get stronger. When it comes to deciding on another drink, the research points the other way.

What the research adds

Lab studies with social drinkers, people who weren't dependent on alcohol, show two things. A small first dose, about the size of one or two drinks for many adults, made people want more. A moderate dose, about two or three drinks, reliably weakened inhibitory control, the ability to hold back from an action you've started (Field et al, 2010). In one small study of 15 social drinkers, the wish for more peaked about half an hour after the larger of two doses (Rose & Duka, 2006).

So after a drink or two, the next one is easier to want and harder to refuse. In everyday terms, the decision about the third drink gets made by a brain that has already had two. These were lab tasks, not evenings at home, and the drink counts are rough.

Grisel's lesson ends with a longer view: with regular drinking, the brain adapts by turning down its own calming and reward signals, so not drinking starts to feel uncomfortable. That's one reason the same evening drink can feel more needed over the years.

How this fits the Reduce your drinking program

The 1h Protocol to Reduce Your Drinking calls this the Slide. Its first paid chapter shows how the cue, the job and the slide carried your last evening past your plan, and chapter 2 sets your number for the evening before it starts. If one drink often becomes several for you, your answers point to the Second Drink pattern, which starts with deciding your number and your ending. The first chapter is free.

Source: TED-Ed, How does alcohol make you drunk?, Judy Grisel, 9 Apr 2020 Research: Field et al, 2010 · Rose & Duka, 2006