Alcohol and substance use
People with untreated ADHD are statistically more likely to develop substance use problems, especially involving alcohol, cannabis, or stimulants.
ADHD involves dopamine dysregulation — people may use substances to self-medicate for low motivation, restlessness, or emotional distress.
Alcohol
You have to be aged 18 or older to legally purchase alcohol.
Drinking alcohol has different effects, including relaxation, lowered inhibitions and impaired judgement.
There are risks of addiction, liver disease, heart issues, mental health impact.
- Do not regularly drink more than 14 units of alcohol per week.
- Spread drinking over three or more days if you drink as much as 14 units a week.
- Have several alcohol-free days each week.
- The 14-unit limit applies equally to men and women.
Find out more about the number of units in different drinks
Alcohol units in common drinks
Beer (4%) ~2 pints = 8 units.
Wine (13%) ~2 large (250ml) glasses = 6 units
Cider (5.5%) ~2 pints = 11 units
Spirits (40%) ~7 single (25ml) shots = 9 units
Caffeine misuse or dependence
Caffeine misuse happens when consumption exceeds safe levels or causes harm to health, mood, or behaviour.
It may lead to dependence — where a person feels unable to function normally without caffeine.
Signs of caffeine misuse:
- Consuming large amounts daily (often >600 mg)
- Feeling jittery, anxious, or restless
- Sleep problems or insomnia
- Headaches or stomach upset
- Needing more caffeine for the same effect (tolerance)
- Withdrawal symptoms (headache, fatigue, irritability) if intake stops suddenly
Things you can do
- Seek support from family and friends
- Stay calm and read our ADHD strategies and support page
- Have open conversations