10 signs you're drinking way too much caffeine

• Coffee isn't addictive in the medical sense of the word, but it does cause a dependency.
• You should limit yourself to about 400 mg of caffeine a day, which is about four cups of coffee.
• Drinking too much caffeine can lead to brain fog, headaches, nausea, irritability, and more.

While we may not view caffeine as a drug, it technically is, since it's a stimulant that affects the central nervous system. In fact, it's the most commonly used drug in the world, and it's estimated that around 90% of adults in North America consume some amount of caffeine daily.

Caffeine is generally considered safe when you limit it to no more than 400 milligrams per day — which is about four cups of coffee. But if you find yourself consuming much more than that, or feeling unable to properly function without large amounts of caffeine, you may have a dependence on it. But, to be clear, you are not addicted to it in the physiological use of the term.

Here's what you need to know about caffeine dependence and how to cut back on caffeine.

What is caffeine dependence?

"When people use the term caffeine addiction, that is incorrect. Technically, caffeine use can result in a physical dependence, but not an addiction," says Cherian. The difference is as follows:

• Dependence: Physical dependence on a drug means that you need more of it to gain the same effects, but you can stop using it if you want to.
• Addiction: An addiction is uncontrolled substance use that results in negative consequences. In other words, you cannot stop using the drug despite how it's negatively impacting your life.

Drug dependence can accompany addiction, but it is not addictive because it does not trigger neurological changes specific to drug addicts.

In particular, caffeine does not damage the orbitofrontal cortex — part of the brain that helps you think rationally — like what researchers have seen in cocaine, heroin, or methamphetamine drug addicts.

That said, caffeine does affect the brain, just in a different, less severe way. It works by blocking adenosine receptors in the brain that make you tired. As a result, you feel more awake and energized, says Vivek Cherian, MD, an internal medicine physician with a private practice.

People become dependent on caffeine when they drink it on a daily basis and develop a tolerance, says Carrie Lam MD, FAAMFM, co-founder and medical director of the Lam Clinic

"As the brain gets acclimated to the higher amount each day, those who stop drinking caffeine abruptly will start to have withdrawal symptoms and cravings," says Lam.

Why caffeine is not addictive

Perhaps where the confusion between caffeine dependence and addiction comes in is because of how caffeine can lead to an increase in dopamine levels similar to addictive drugs like cocaine.

By blocking adenosine receptors, caffeine allows, "other natural stimulants in our body, such as dopamine, to be more effective," says Cherian.

However, the amount of dopamine released is not nearly large enough to cause the same types of surges as addictive drugs. Therefore, caffeine can't activate the same reward circuits in the brain linked to true addiction.

Moreover, caffeine withdrawal symptoms can be uncomfortable but they are not life-threatening the way withdrawal can be if you're addicted to alcohol, MDMA, Xanax, or just about any other addictive drug out there.

Signs of a caffeine dependency

The main sign of caffeine dependency is that you are unable to perform daily activities without caffeine.

"If you're unable to function without your daily cup of coffee in the morning there's a decent chance you are dependent on caffeine," says Cherian.

Additionally, if you don't have your caffeine fix, Cherian says you may have withdrawal symptoms that start as early as 12 hours after your last caffeine dose, such as:

1. Headaches
2. Fatigue
3. Irritability
4. Brain fog
5. Difficulty concentrating
6. Nausea

There may be behavioral aspects of caffeine dependency too, Lam says. These include:

1. Wanting to cut down or control caffeine use, but have difficulty doing so
2. Consuming more caffeine over time than you'd like to
3. Continuing caffeine use despite experiencing negative side effects of caffeine
4. Caffeine interfering with your daily life

How to cut back on caffeine

If you've decided it's time to cut back on caffeine use, there are various methods that can help you.

1. Keep a caffeine diary

When you're consuming large quantities of caffeine daily, it can be useful to keep a log of how much you are actually consuming, says Lam. This helps you to be conscious of how much you consume and can allow you to understand triggers that make you spring for caffeine.

A 2016 study found that excessive caffeine drinkers (over 600 milligrams a day) were able to significantly cut back on consumption by keeping a caffeine diary, alongside counseling.

2. Decrease caffeine gradually

To avoid harsh withdrawal symptoms, decrease your consumption gradually rather than stopping cold turkey.

For example, Lam says you can decrease by one cup a day or every couple of days, reducing your intake little by little. You still may experience withdrawal, but it can be less severe this way.

3. Replace high-caffeine drinks with alternatives

Opting for beverages with a lower caffeine content can help you decrease your intake while still providing a boost. For example, Lam says you can drink black tea or green tea, which still has caffeine, but less than coffee or energy drinks.

4. Get enough sleep

"Coffee isn't the best weapon to fight low energy –– it's sleep," says Lam. Therefore, she recommends getting quality sleep, avoiding naps, and going to bed at the same time every night so you won't be as tired in the first place, leading you to consume more caffeine.

5. Stay hydrated

Drinking enough water can help dilute the strength of the caffeine, and also help the kidneys detoxify caffeine and its metabolites quicker, says Lam. Plus, drinking something else like water also gives your mouth and hands something to stay busy when you ditch your coffee mug or other caffeinated drink of choice, says Lam.

Insider's takeaway

Caffeine dependence can cause you to feel like you need caffeine to function, and you may experience withdrawal symptoms ranging from headaches to nausea if you don't get your daily caffeine fix.

With persistence and dedication, however, cutting back on caffeine and breaking the cycle of dependence is possible.