The effect of regular caffeine consumption and caffeine withdrawal on the desire for caffeinated drinks
Many of us enjoy a daily cup of coffee, and some people feel they cannot start the day without one. But what truly drives our desire for caffeine? Researchers at the University of Sussex are looking into two ideas. The first is that we drink coffee to stop withdrawal symptoms, such as tiredness or headaches. The second is that regular caffeine changes how our brain responds, creating a strong urge or 'wanting' for the drink. To test this, the researchers are inviting healthy adults aged 18 to 50 who drink either a lot of coffee or very little coffee. Volunteers will attend two separate lab sessions where they drink a lemon and ginger tea containing either a modest amount of caffeine or no caffeine at all. The results will help scientists better understand everyday habits and caffeine dependence.
At a glance
What is this study about?
Coffee is one of the most popular drinks in the world. Many people feel dependent on their morning brew, but scientists are still trying to understand the exact reasons behind this habit. Does our daily cup simply stop us from feeling sluggish and irritable, or does regular caffeine use 'rewire' our desire so that we crave it even more?
This clinical study explores two main ideas. The first idea is that people drink coffee to avoid unpleasant feelings, like tiredness, that happen when caffeine wears off. The second idea is that caffeine triggers reward pathways in the brain, making us strongly want another drink even if we do not consciously realise it.
By comparing people who drink coffee heavily with those who drink very little, the researchers hope to see how caffeine affects mood and cravings in both groups. Understanding how these habits form can give scientists wider clues about how the brain handles cravings, routines, and mild dependencies in everyday life.
Key takeaways
- Tests why we crave coffee: to stop tiredness or because of brain habit loops.
- Open to healthy adults aged 18 to 50 who drink coffee either rarely or frequently.
- Involves two short visits to the University of Sussex lab, at least one week apart.
- Uses a standard dose of caffeine (100 mg) dissolved in herbal tea.
- Volunteers are compensated with cash or university credits.
Who may be eligible?
This study is looking for healthy men and women aged between 18 and 50. To take part, you must be a coffee drinker who falls into one of two groups: either a high consumer who drinks more than two cups of coffee a day, or a low consumer who drinks less than one cup a day.
You cannot take part if you do not drink coffee at all. To keep the test results clear and safe, volunteers must not have diabetes and should not be taking regular prescription medicines, although women taking the contraceptive pill are very welcome to join.
Finally, the researchers need people who do not use nicotine products. You will not be able to take part if you vape or smoke more than five cigarettes in a week.
Could this study suit you?
Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.
- Are you between 18 and 50 years old?
- Do you drink either more than 2 cups of coffee a day, or less than 1 cup a day?
- Are you generally healthy and free from diabetes?
- Are you free from regular prescription medications (apart from the contraceptive pill)?
- Do you avoid vaping and smoke 5 or fewer cigarettes a week?
What does participation involve?
If you decide to take part, you will be asked to attend two test sessions in a laboratory at the University of Sussex. These visits will take place on different days, at least one week apart.
During each session, you will be given a cup of lemon and ginger tea. In one session, the tea will have 100 milligrams of caffeine mixed into it (roughly the amount found in a standard mug of brewed coffee). In the other session, the drink will be a 'placebo' dummy drink with no caffeine, tasting exactly the same. Neither you nor the study team will know which drink you receive first.
You will complete simple tasks and answer questions so researchers can measure your cravings, mood, and how much you like and want caffeinated drinks. The entire study takes place over a couple of weeks, with minimal time needed outside the two visits.
Potential risks and benefits
Locations (1)
- University of SussexApproximateBrighton, England
Common questions
What is the drink used in the study?
You will drink a warm lemon and ginger tea. In one visit, it will contain 100 mg of caffeine, and in the other visit, it will contain no caffeine.
Will I be paid for taking part?
Yes. Volunteers receive either a cash payment for their time or course credits if they are University of Sussex students.
Can I take part if I vape or smoke?
You can only join if you do not vape and smoke no more than five cigarettes per week, as nicotine can alter how the body responds to caffeine.
Can I join if I am on the contraceptive pill?
Yes. While most other prescription medicines are not allowed for this study, the oral contraceptive pill is completely fine.
Where does the study take place?
The study takes place in person at the University of Sussex campus in Falmer, near Brighton.
How to find out more
Tatum Sevenoaks
Always speak to your GP or specialist before deciding to take part in a study.
Discussion
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