In This Article
What is Caffeine?
Caffeine is a bitter substance that’s naturally present in over 60 plants. Common caffeine sources include coffee beans, tea leaves, kola nuts, and cacao pods.1
According to the World Health Organization (WHO), caffeine is one of the most widely used psychoactive substances around the world.2
In the U.S., over 85% of adults and children regularly consume coffee, caffeinated soda, and caffeine-containing foods.3, 4
How Caffeine Works
In terms of chemical structure, caffeine closely resembles the molecule adenosine. Adenosine attaches to adenosine receptors in the brain, which causes tiredness.
Caffeine is an adenosine antagonist, meaning it blocks adenosine receptors. This action produces alertness until the body metabolizes caffeine.
Caffeine also removes adenosine’s negative effect on dopamine receptors, stimulating dopamine release. Dopamine is a brain chemical that activates feelings of reward and motivation.
Paraxanthine, which is a major metabolite of caffeine, also increases dopamine levels and locomotor activity.5
Health Effects of Caffeine
Caffeine stimulates the central nervous system (CNS) and produces effects like:1, 5
- Alertness or liveliness
- Sense of well-being
- Boosted energy
Caffeine is also shown to reduce the risk of other health issues like stroke, Parkinson's, and Alzheimer's.6
Side Effects of Caffeine
Caffeine intake is relatively safe in low to moderate amounts. The WHO recommends not to consume more than 200 mg in one sitting (2½ cups of coffee) or 400 mg per day (five cups of coffee).6
Drinking (or taking) more than the recommended amount may lead to adverse side effects like:1
- Insomnia or sleep disruptions
- Dehydration (due to caffeine’s diuretic effect)
- Increased stomach acid, which can lead to acid reflux or heartburn
- High blood pressure (hypertension)
- Increased heart rate
- Caffeine tolerance
- Caffeine dependency
Some caffeine users may develop tolerance over time. This means their usual doses no longer produce the same result. They will need more caffeine to get the same effects.
People experience side effects differently due to varying caffeine tolerances. For example, some people may find it hard to sleep if they don’t drink much coffee.
Some users may eventually become dependent on caffeine. They will experience withdrawal if they stop taking or drinking caffeine.
What is Caffeine Addiction?
Caffeine triggers dopamine release, which produces a euphoric feeling.
People may want to consume caffeine repeatedly to experience this euphoric effect. They may take caffeine in higher doses or for extended periods, which might lead to caffeine addiction.
The American Psychiatric Association’s (APA’s) Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5) lists caffeine as one of the ten addictive substances. It has nine criteria for diagnosing caffeine addiction, which is fewer than the 11 DSM-5 criteria for alcohol, opioids, and other substances.
A person is diagnosed to have problematic caffeine consumption if three or more of the following DSM-5 criteria are met:5, 7
- Strong desire to use caffeine
- Unsuccessful efforts to stop or control caffeine consumption
- Continued caffeine intake despite physical or psychological problems caused or worsened by caffeine
- Continued caffeine intake, despite social or interpersonal problems caused or aggravated by caffeine
- Taking caffeine in higher doses or for an extended period
- Failure to fulfill work, school, or home obligations due to caffeine use
- More time spent on obtaining caffeine, using caffeine, or recovering from caffeine’s effects
Symptoms of Caffeine Withdrawal
Like alcohol and other addictive substances, people who abruptly stop caffeine use may experience withdrawal.
Symptoms of caffeine withdrawal include:1, 5, 8, 9
- Depressed mood
- Difficulty concentrating
- Flu-like symptoms (like nausea, vomiting, or muscle pain or stiffness)
Caffeine withdrawal is the result of increased sensitivity to adenosine during caffeine abstinence. Caffeine is no longer present to block adenosine from attaching to brain receptors.5
Classifying Caffeine Addiction
The National Institute on Drug Abuse (NIDA) describes excessive caffeine consumption as dependency, not addiction.
While caffeine activates dopamine release, the outcome isn’t large enough to disrupt the reward system as with other stimulants like amphetamines and cocaine.10
The DSM-5 does not recognize caffeine addiction as a substance use disorder (SUD). It does, however, acknowledge caffeine addiction as a condition for future study.3, 5
The WHO, through the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10), was the first to recognize caffeine dependence syndrome as a clinical disorder.5, 11
Steps to Overcome Caffeine Addiction
There’s no formal treatment yet for caffeine addiction, though these tips are helpful:
- Ask your doctor how you can reduce caffeine dependence.
- Consult your doctor if you use caffeine to cope with depression or other mental health disorders.
- Don’t quit cold turkey. Gradually taper your caffeine consumption to reduce the likelihood of withdrawal symptoms.
- Replace your caffeinated drink with a caffeine-free option (like hot water with lemon).
Exercise. Even a short burst of activity can produce the same boost in energy and alertness from consuming caffeine.12