Caffeine is a central nervous system stimulant, and consuming too much can lead to symptoms of anxiety. These can include restlessness, feelings of uneasiness, and rapid heartbeat.

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Caffeine is the psychoactive drug that people consume the most in the world. It is the second most consumed beverage after water, at 1.6 billion cups per day.

A survey conducted in the United States reports that approximately 85% of the population drinks at least one caffeinated beverage every day.

While many people drink caffeine to help them “wake up” and to stay alert, too much caffeine can have a negative effect on people, leading to numerous side effects, including some symptoms of anxiety disorders.

An anxiety disorder is a mental illness in which a person is overwhelmed with feelings of fear and uneasiness that interfere with daily life. The National Institute of Mental Health (NIMH) estimates that 31.1% of all adults in the U.S. will experience an anxiety disorder at some point in their lives.

Readers should note that there is a large distinction between having a formal anxiety disorder and feeling some symptoms similar to anxiety that may be worsened by drinking coffee.

Keep reading to learn more about the connection between caffeine intake and anxiety, including the symptoms, as well as how to consume caffeine safely in order to avoid triggering or worsening anxiety symptoms.

A literature review describes the many effects that caffeine has on the body. One of its main mechanisms of action is to block adenosine receptors, causing increases in dopamine, noradrenalin, and glutamate. In the cardiovascular system, this increases a person’s blood pressure and heart rate. In the central nervous system, lower doses of caffeine can improve motor activity and alertness, while higher doses can produce symptoms of anxiety.

Evidence from genetic studies found that adenosine receptor genes play a role in the development of anxiety. This suggests that some individuals may have an increased risk of anxiety disorders and that caffeine may make them more susceptible. More studies are needed in this area.

The Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association, recognizes caffeine-induced anxiety disorder as a condition in which caffeine interferes with daily functioning. To meet the criteria for this diagnosis, a person must have symptoms of anxiety directly caused by the consumption of caffeine.

The DSM-5 has also proposed criteria for caffeine use disorder, in which all three of the following criteria must be met:

  • persistent desire or unsuccessful effort to control caffeine use
  • use of caffeine despite harm
  • symptoms of caffeine withdrawal

Although this is not yet an official DSM diagnosis, it provides researchers with a framework to conduct further studies.

The symptoms of overuse of caffeine and the symptoms of anxiety can overlap.

Symptoms of using too much caffeine include:

  • nausea
  • dizziness
  • dehydration
  • headaches
  • restlessness
  • rapid heartbeat
  • insomnia
  • anxiety

Symptoms of anxiety typically include:

  • feelings of fear, dread, and uneasiness
  • excessive worry
  • sweating
  • restlessness
  • tenseness
  • rapid heartbeat

Overuse of caffeine can cause anxiety symptoms, and on the flip side, symptoms of anxiety may become worse with the use of caffeine. If a person is concerned about their coffee intake, they should speak with a doctor.

Studies show that there are health benefits of moderate doses of caffeine. Some of these benefits include improvements in mental alertness, concentration, fatigue, and athletic performance. Other benefits may include weight loss, lower risk of diabetes, reduced risk of Parkinson’s disease, and reduced risk of cancer.

The FDA issued guidance in 2012 stating that for healthy adults, caffeine consumption at less than 400 mg/day is not associated with adverse effects.

Results from a 2014 survey in the U.S. found that for all ages combined, the average intake of caffeine from all beverages is 165 milligrams (mg)/day. This is about the amount in 1–2 cups of regular coffee. The FDA state that any intake up to 400 mg of caffeine a day should not lead to adverse health effects. This is equivalent to about 3–4 cups of coffee.

Some groups of people, or those with certain health conditions, should talk with their doctor to determine if they should limit or avoid caffeine. These include people who:

  • are pregnant
  • are breastfeeding
  • have insomnia
  • experience migraines or chronic headaches
  • have anxiety
  • have stomach disorders such as ulcers
  • have an irregular heart rate or rhythm
  • have high blood pressure
  • take certain medications including stimulants, some antibiotics, asthma medications, and heart medications
  • are children and teenagers

Health and regulatory agencies have cautioned about the use of caffeine in these populations.

Of particular concern is the popularity of energy drinks in young people, with their high levels of both caffeine and sugar. There are also concerns about the effects of combining alcohol and caffeine.

The best way to provide more information about safe levels of consumption of caffeine needs to be determined.

The first step in making informed decisions is for a person to be aware of the caffeine content of beverages. Label reading and daily planning can help avoid the adverse consequences of excessive caffeine consumption.

People who want to reduce or limit their caffeine consumption should do so gradually. This will help avoid symptoms such as headache, fatigue, irritability, drowsiness, difficulty concentrating, and nausea.

The caffeine content of beverages was measured in the 2014 survey cited above. The investigators grouped them into several general categories:

BeverageCaffeine Content (mg/fluid ounce)
Regular coffee4-21
Espresso47-63
Decaffeinated coffee0.25
Carbonated soft drinks, caffeinated, regular or diet2-7
Tea, caffeinated, regular or diet1-8
Energy drinks3-20
Energy shots40-70
Chocolate milk0.2-2

It is important to note that there were limitations in determining the amount of caffeine in the beverages included within the table. The study authors state that while most commercially available drinks have caffeine content listed on the label, for teas and coffees that are made to order, the content can vary widely. The caffeine content can depend on the origin of the crop, processing, and preparation.

Many people rely on the jolt of energy that caffeine provides to get them going in the morning. This can sometimes come with negative consequences, such as development or worsening of anxiety symptoms.

Decaffeinated coffee or tea may be a good alternative for many people. These beverages tend to have a similar flavor, however, they may not provide the energy boost that caffeine does. Once a person successfully weans themselves from caffeine, however, these can be a calming choice.

There is a vast array of herbal teas available. They are popular throughout the world and have numerous health benefits.

Some people find that exercise can be a great way to start the day. A walk or run outside, or a jog on the treadmill indoors, can be a good way to get blood flowing and clear brain fog. Drinking water can also help people wake up.

There is an association between the overuse of caffeine and anxiety. The effects of having too much caffeine can mimic symptoms of, or worsen anxiety.

People who experience caffeine-induced anxiety should avoid or reduce their consumption of caffeine.

It is important to be aware of the caffeine content of many commonly consumed beverages. With careful planning, people can make informed choices to reduce or avoid the use of caffeine.