Please note this information is not medical advice, and for advice on your specific needs you should always consult your medical practitioner.
For some people, coffee is what keeps them alert, awake and energetic. Caffeine in coffee directly affects the central nervous system, thus producing a stimulatory effect. In fact, caffeine is the most widely used psycho-stimulatory drug in the world . According to McCrindle.com, 75% of Australians consume at least one cup of coffee daily and 28% of them consume three or more cups per day .
However, several studies report that caffeine can aggravate the symptoms of anxiety in some people, especially in those who are prone to psychological disorders  . Diagnostic and Statistical Manual of Mental Disorders (DSM-5) lists “caffeine-induced anxiety disorder” as one of the caffeine-associated disorders . Australian alcohol and drug foundation (ADF) states that regularly consuming more than 4 cups of coffee per day can cause symptoms related to anxiety .
What is anxiety?
Anxiety is the body’s response to a threatening situation—real, or perceived. Anxiety symptoms include rapid heart rate, rapid breathing, stomach problems, and uneasiness. Although everyone experiences anxiety from time to time, some people may undergo prolonged episodes of anxiety. These conditions are characterized as anxiety disorders and require medical treatment. Anxiety disorders are the most prevalent mental disorder in Australia and it affects 25% of Australians .
Caffeine, stress and anxiety
Upon ingestion, caffeine gets rapidly absorbed into the blood and reaches a peak value within 60-90 minutes of consumption . Being soluble in lipids, caffeine readily crosses the blood brain barrier and directly stimulate the brain .
Caffeine acts by binding to adenosine receptors in the brain, thus inhibiting the action of adenosine . Adenosine receptors have found to be important in mediating anxiety and stress responses . Caffeine, an adenosine receptor blocker, is known to exert an anxiogenic effect –. In addition, shutting down adenosine receptors can leave the body more awake and tired in the long run, reducing the body’s ability to relax.
Caffeine also stimulates the secretion of adrenaline (also known as epinephrine) and cortisol . Secretion of adrenaline and cortisol also intensifies the symptoms of anxiety and stress by activating the “fight or flight” response of the body , .
High doses of caffeine can cause symptoms such as elevated blood pressure, rapid heartbeat, irritability, and sleeplessness—all of which represent anxiety. For people suffering from anxiety disorders, it can be hard to differentiate between these symptoms and real anxiety , . Thus, caffeine can exacerbate the anxiety disorders.
Caffeine can also interact with anxiety medication, and interfere with their activity . For people experiencing caffeine dependence, cutting off caffeine can cause withdrawal symptoms including anxiety .
Limiting caffeine intake
According to the FDA, a healthy person can consume 400mg of caffeine (amount of caffeine in 4-5 cups of coffee) per day . However, this upper limit of caffeine consumption can vary depending on individual factors such as the body weight, genetics, and medications taken.
Studies suggest that people suffering from anxiety disorders can benefit from limiting or cutting off their caffeine intake , .
People aiming to limit their caffeine consumption should watch their diet for caffeine containing foods and beverages such as coffee, tea, energy drinks, and chocolate. Switching from regular coffee to decaffeinated coffee is one way to reduce the amount of caffeine in diet.
Moreover, it is best to cut back caffeine in a gradual manner. Quitting caffeine cold turkey may not be the wisest decision as it can cause caffeine withdrawal, thus triggering—or worsening—anxiety episodes.
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