Many begin to drink alcohol during adolescence. Should we be worried or is this just what teenagers do?

What the Research Tells Us

Credit: Brainwave Trust Aotearoa

Alcohol use is deeply ingrained in many societies, and for many young people, drinking begins during adolescence. But while some may see this as a normal part of growing up, research suggests there are serious reasons to be concerned.

The adolescent brain is not fully formed, making it particularly vulnerable to the effects of alcohol.

How adolescent brains develop

Unlike adults, adolescents experience a gap between emotional and cognitive maturity. The limbic system, which governs emotions and reward-seeking behaviour is highly active during puberty. Meanwhile, the prefrontal cortex, responsible for impulse control and decision-making, is still developing into the mid-20s.

🔹 What does this mean?
Teenagers seek novelty and take risks, but their ability to regulate these impulses lags behind, making them more susceptible to dangerous behaviours, including heavy drinking.

Alcohol’s impact on the teenage brain

Alcohol poses both immediate and long-term risks for adolescents. Beyond the obvious dangers such as car accidents, injuries, violence, and risky sexual behaviour, alcohol consumption during this developmental stage can cause lasting changes to brain function and structure.

1. Increased risk of dependence

The younger someone starts drinking, the greater the risk of developing alcohol dependence later in life. Research shows that:

📌 More than 40% of people who start drinking before age 15 will develop alcohol dependence.
📌 That risk drops to just 10% for those who begin drinking after age 20.

(Grant & Dawson, 1997)

2. Adolescents are less sensitive to the warning signs

It’s often assumed that teenagers are more affected by alcohol than adults because they have less drinking experience. Surprisingly, the opposite may be true.

🔹 Adolescents are less sensitive to the negative effects of alcohol, such as sleepiness and loss of motor coordination.
🔹 They bounce back faster from hangovers, reducing natural deterrents to heavy drinking.
🔹 They are more sensitive to alcohol’s pleasurable effects, which may increase the likelihood of binge drinking.

💡 What does this mean?
Since teens don’t feel the effects of alcohol as strongly, they may drink more before realising they’re intoxicated, increasing the risk of accidents, blackouts, and alcohol poisoning.

(Windle et al., 2008; Doremus et al., 2003)

3. Alcohol can alter brain structure & function

Heavy drinking during adolescence physically changes the brain. Research has shown structural damage in key areas, including:

✔️ Hippocampus (memory & learning) - Shrinking in heavy-drinking adolescents (Medina et al., 2007).
✔️ Prefrontal Cortex (decision-making & impulse control) Reduced volume in heavy drinkers (De Bellis et al., 2005).
✔️ Corpus Callosum (communication between brain hemispheres) - Damage in adolescents who drink heavily (Tapert et al., 2003).
✔️ White Matter Integrity - Disruptions in brain connectivity linked to binge drinking (McQueeny et al., 2009).

4. Gender differences

Emerging research suggests that alcohol may affect girls and boys differently.

📌 Girls may be more vulnerable to alcohol’s effects on the frontal lobe, which is responsible for reasoning and self-control.
📌 Boys may experience more pronounced impairments in motor function and coordination.

(Tapert et al., 2004/5)

5. The adolescent brain works harder to compensate

Studies using brain scans show that young people who drink heavily require more brain effort to complete simple tasks.

With continued heavy drinking, the brain’s ability to compensate declines, leading to poorer performance on cognitive tasks.

Why delaying alcohol use matters

The adolescent brain is uniquely sensitive to alcohol’s effects, making underage drinking far more harmful than it might seem.

✔️ Starting to drink later in life significantly reduces the risk of alcohol dependence.
✔️ Binge drinking is particularly damaging—it’s not just how much teens drink, but how they drink.
✔️ Alcohol changes brain structure and function, affecting memory, learning, and decision-making.

By delaying alcohol use, parents, caregivers, and communities can help protect young people’s brains and long-term well-being.

📌 For the full research article, visit: Brainwave Trust Aotearoa