As the pandemic unfolded, many restaurants and bars took a dive, as the masses turned to their computers for virtual happy hours. But it wasn't just tech companies like Zoom that got it right. Sales of alcohol of liquor stores and delivery services soared in 2020. Many states even relaxed laws so that deliverers could transport hooch to their customers. Essentially, the extreme conditions of 2020 have not hindered our ability or tendency to grab a drink.
All of that – combined with the “dry January” trend – makes it a good time to think about what defines an alcohol use disorder (AUD). And more specifically, can you get AUD if you don't drink every day?
The answer is yes, absolutely, according to the experts and a lot of research. In fact, the diagnostic criteria for AUDs does not explicitly refer to the frequency or amount of drinking at all. Rather, the disorder is determined by the impact of drinking on your life.
Research shows that heavy drinking seems to have huge effects on the brain, even in people who don't participate in it every day. Over time, it causes changes in the way neurons throughout the brain talk to each other using chemical messengers or neurotransmitters. "There is probably no neurotransmitter system that is in some way unaffected by alcohol," said Jeffrey Weiner, a professor of physiology and pharmacology at Wake Forest School of Medicine.
Defining an alcohol use disorder
An AUD is rated on a spectrum and can be diagnosed as mild, moderate, or severe, based on answers to important questions. It takes into account things like: Did you drink more than you intended in the past year? Does drinking – or being sick from drinking – hinder school, work, or other responsibilities?
The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) lists 11 questions to that effect. If you answer yes to two or three questions, you will be diagnosed with mild AUD. If you answer yes to six or more, your AUD is considered serious. The different levels of the condition are based on years of continued research into the relationship between the human brain and alcohol.
When you take your first drink
Alcohol is biphasic, says Rajita Sinha, a professor of psychiatry and neuroscience at Yale School of Medicine. This means that drinking some alcohol will initially make you feel stimulated and uninhibited, but consuming a little more will make you sleepy. This distinction is important, explains Sinha: "We use (alcohol) because it changes our mood." That curve – how much alcohol you need to switch from uninhibited to sleepy – changes very quickly the more you drink.
When you start drinking, alcohol immediately acts on two neurotransmitters. It increases the amount of GABA, a neurotransmitter that reduces brain activity, and decreases the amount of glutamate, a neurotransmitter that stimulates brain activity. The result is an overall reduction in brain activity, which makes you feel uninhibited and ultimately slows down your thoughts, speech and movement.
All addictive drugs and even many activities, such as gambling and eating sweets, have one thing in common – they activate the dopamine reward circuitry. This circuit is made up of different parts of the brain that respond to an increase in the neurotransmitter dopamine and make us feel the need or desire to repeat the behavior that triggered the wave.
Weiner explains that reward circuit is a bit of a misnomer. In most cases, these neurons get an increase in dopamine when we perform an activity we find enjoyable or rewarding – from eating sugar to gambling – but their main function is to make us feel the need to repeat our behavior over and over. And this effect can persist even when the activity is no longer enjoyable. As a result, the neurons can encourage a person to continue to drink heavily, even if they have suffered negative consequences.
Longer-term changes begin
It doesn't take long for someone to start drinking to avoid stress, says Natalie Zahr, an assistant professor at Stanford University who studies how alcohol affects the brain. Researchers have observed changes in the brain's stress and reward systems, even in teens who drink only on weekends.
Sinha and her team have too given chemical signs of this shift in heavy drinkers who they specifically wanted to study because they did not still meet the diagnostic criteria for an AUD. In their study, participants were considered heavy drinkers if they drank at least eight drinks per week (women) or 15 drinks per week (men) and reported that they sometimes drank more than four drinks (women) or five drinks (men) at one time .
The study shows that the heavy drinkers had higher levels of cortisol – the stress hormone – than moderate drinkers. These individuals have cortisol "circling around a different baseline," Sinha explains. Their cortisol levels stay high between drinks, never dropping to the levels seen in moderate drinkers.
The heavy drinkers also reported increased cravings for alcohol. And while both heavy and moderate drinkers drank a little more after being exposed to stress, the heavy drinkers increased their intake much more dramatically.
Can the brain reset?
There is another particularly insidious difference in the brain of a heavy drinker. The prefrontal cortex – the part of the brain directly behind the forehead responsible for logic, planning, and impulse control – has been damaged. "We think this gives rise to many of the behavioral symptoms associated with AUD," Weiner says.
Zahr adds that disruption of the frontal systems makes it more difficult to stop drinking because this part of the brain is needed to help people decide not to drink based on the potential risks of drinking.
Weiner says prefrontal cortex dysfunction is not exclusive to AUDs. It often occurs with other neuropsychiatric disorders such as PTSD and anxiety. It also turns out that a weakened prefrontal cortex makes people more prone to developing an AUD. "We study people with anxiety disorders, and with an anxiety disorder, your vulnerability to developing an AUD will certainly increase."
While there are some options to help people with AUD drink or quit, all three experts believe there is room for improvement. Some people find success with Alcoholics Anonymous or cognitive behavioral therapy. There are drugs designed to respond to some of these disturbances in the brain, but scientists are still looking for better tools, ranging from therapy and pharmaceuticals to deep brain stimulation or transcranial magnetic stimulation, which they hope can help restore balance in the brains of patients with AUDs. The biggest problem, however, is that less than 10 percent of those with an AUD receive treatment at all.
For those who can, Sinha says, simply taking a break from drinking, such as participating in challenges during a dry month, can help. In A study her team reported last year, the longer someone drank without alcohol, the less hard drinking days they had when they started drinking again. "What we found is that under normal circumstances, for people who abstain for a good period of time – a month or two months – they definitely restore some of these circuits to function," says Sinha.