Caffeine is the world’s favorite mood-altering drug. It is an extremely powerful, psychoactive substance and it is found in more than 60 known species of plants, and dietary sources include coffee, tea, cocoa beverages, chocolate and soft drinks.
Coffee was consumed in Arabia in the 13th century and was introduced into Europe in the early 17th century so no wonder that coffee consumption became perfectly normal throughout all these centuries.
‘. . . coffee sets the blood in motion and stimulates the muscles; it accelerates the digestive processes, chases away sleep, and gives us the capacity to engage a little longer in the exercise of our intellects.’ Honoré de Balzac (paraphrasing Brillat-Savarin) Traité des Excitants Modernes (1838).
But, the potential harmful effects of caffeine have long been recognized. As long ago as 1900, the Journal of the American Medical Association reported a conference on ‘Coffee as a beverage: its deleterious effects on the nervous system’, at which a contributor complained that ‘most physicians had given the subject little if any attention’. Another contributor asserted that coffee could cause a variety of symptoms, including depression, irritability, insomnia, tremulousness, loss of appetite and ‘frequent eructations of gas’ (JAMA, 2001).
Four caffeine-related syndromes are recognized in DSM–IV (American Psychiatric Association, 1994): caffeine intoxication; caffeine-induced anxiety disorder; caffeine-induced sleep disorder; and caffeine-related disorder not otherwise specified. (Source: BJPsych Advances).
The Johns Hopkins Baview Medical Center provides estimation that adults consume approximately 280 milligrams per day in the United States and that
- 100 mg of caffeine per day can lead to physical dependence and withdrawal symptoms upon ceasing to consume caffeine.
- 200 mg of caffeine per day can increase anxiety ratings and induce panic attacks for some individuals.
- Caffeine intoxication can occur for some individuals when they consume caffeine in excess of 250 mg (more than 2-3 cups of brewed coffee) per day.
People already susceptible to panic attacks an anxiety in general are more prone to the psychological effects of caffeine. Caffeine stimulates central nervous system and can significantly contribute to anxiety and related conditions and symptoms including insomnia, irritability, racing heart, heart palpitations, and even panic attacks.
People susceptible to increased anxiety related to caffeine intake have a slight genetic variation in their adenosine receptors which not only are responsible for caffeine’s awakening effects but also regulate person’s sense of anxiety.
A well-conducted study, published in 2003 which was a joint project in part by the Department of Psychiatry, The University of Chicago and The Department of Psychiatry, University of Munster, Germany1 found that genetic differences in people’s Adenosine receptors were likely responsible for caffeine-induced anxiety.
The team looked at 3 different genotypes involving adenosine receptor genes to see if any of them would indicate whether or not a person would have increased anxiety when consuming caffeine.
They found that people with an A2a receptor gene difference seem to be especially at risk of experiencing increased anxiety when consuming coffee, tea, energy drinks, or other caffeine-containing products.
Both the A1 and the A2a adenosine receptors in a person’s brain are thought to also regulate how a person deals with stress and anxiety. Since caffeine binds to these receptors, it is thought to interfere with anxiety regulation.
Therefore, those that have the A2a gene difference could experience increased anxiety when consuming caffeine (Source: caffeineinformer).