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Chris Choi was grabbing his Veranda Roast grande (he takes it black) at an L Street NW Starbucks in downtown Washington on Monday morning, his first of the day. “It’s very trendy to drink coffee,” said Chris, 23, “You’ll never be judged going out and getting coffee. You find more people into that.”[1]
I’m not a great coffee drinker, but I know many people are. One a day is often just enough for me. However, in the last couple of decades, the expansion of coffee shops and coffee capsule systems has seen an increase in the popularity of coffee consumption – especially among Millennials (19 to 34-year-olds). Migration from the countryside to the cities in countries such as China has also led to many people trying coffee for the first time and finding they like it. But this increase in the popularity of coffee may be one of the factors fuelling our modern feelings of existential dread. Many people overlook the fact that caffeine indirectly increases norepinephrine and causes symptoms essentially indistinguishable from anxiety, including nervousness, irritability, trembling, palpitations, flushing, and heartbeat irregularities. The more caffeine you consume in a day, the more these symptoms are likely – and not just in adults, but also in children. A study by Gareth Richards and Andrew Smith at Cardiff University studied the weekly caffeine intake of 3071 secondary school pupils. They found that after adjusting for effects of diet, demography and lifestyle, there were significant positive correlations between total weekly caffeine intake and measures of anxiety[2], with coffee being the major contributor to these school kids’ caffeine intake.
Many people are clearly unaware of the relationship between caffeine and anxiety symptoms. In 1974, John Greden, then Assistant Professor of Psychology at the University of Michigan Medical Center wrote a brief but influential paper entitled Anxiety or Caffeinism: A Diagnostic Dilemma. In this paper he reports the case of an ambitious 37-year-old army lieutenant colonel referred to a military medical clinic because of a 2-year history of chronic anxiety. His daily symptoms included dizziness, trembling, apprehension about his job performance, butterflies in the stomach, restlessness, and difficulty sleeping. He was proud of the fact that his coffeepot was a permanent fixture on his desk, and admitted drinking eight to 14 cups of coffee a day. It was suggested to him that coffee toxicity might be causing his symptoms. He responded with incredulity and refused to limit his intake of coffee, cocoa or cola. When his symptoms persisted, he then agreed to voluntarily reduce his caffeine intake, and almost immediately most of his physical symptoms improved, as did his scores on the Hamilton Anxiety Scale. His job apprehension still persisted, but he cynically observed that he was “still working for the same S.O.B.”!
So why am I banging on about the link between caffeine consumption and anxiety symptoms? First, because our contemporary coffee culture may be genuinely contributing to modern feelings of pervasive “existential dread” reported by writers such as Scott Stossel in his book My Age of Anxietyand blogging journalists who’ve noted the puzzling growth of anxiety in the modern age[3]. The sheer volume of coffee consumption may not be as great as it has been in the past (I think coffee consumption in the United States peaked as long ago as the 1940s), but it’s a modern-day culturally popular beverage delivered by trendy coffee shops and convenient coffee capsule machines that we’re told every home should have (yes, there’s one in our house!). What’s different in the modern era is that the current generation is much more aware of anxiety symptoms than were coffee drinkers twenty or thirty years ago. So we may be acutely aware today of our caffeine-induced anxiety symptoms but not necessarily aware that these symptoms may in part be attributed to our coffee consumption.
But secondly, caffeine is regularly used in what are known as “biological challenge procedures” used in research on panic disorder, and these studies tell us some interesting things about what triggers panic attacks and how panic disorder develops out of just a few isolated panic attacks. The million-dollar question is why some people experience isolated panic attacks, brush them off, and continue with life as normal, whereas others fall sharply into the snake pit of regular, debilitating attacks that stymy all aspects of life for months and even years.
A biological challenge procedure is where a provocative agent is used to induce panic attacks, and this can tell us whether individuals suffering panic disorder have a greater sensitivity to such agents. Dennis Charney and colleagues from Yale University School of Medicine administered 10mg of caffeine to 21 patients with a diagnosis of panic disorder and 17 healthy control participants. Caffeine produced significantly greater increases in self-rated anxiety, nervousness, fear, nausea, palpitations, and tremors in the panic disorder patients than the controls. Caffeine also induced symptoms identical to full-blown panic attacks in fifteen of the 21 patients[4], but not in the healthy controls. Other provocative agents that produce similar results include carbon dioxide (CO2) inhalation, sodium lactate, the drug yohimbine, and even something as basic as voluntary room-air hyperventilation[5].
The face-value conclusion from these wide-ranging studies is that individuals with a diagnosis of panic disorder have a significantly greater sensitivity to provocative agents than do individuals without a diagnosis of panic disorder. But that doesn’t tell us where that added sensitivity resides. There are many who believe that this added sensitivity resides somewhere in the sufferer’s biology - perhaps an added sensitivity in the brain’s fear centre, the amygdala[6], or overactivity in the body’s noradrenergic neurotransmitter system[7]. There is certainly evidence that’s consistent with both these possibilities. But that evidence isn’t conclusive, because most of the studies have identified these added biological sensitivities in individuals who already have panic disorder, so we don’t know whether these added sensitivities are merely consequencesof having panic disorder or whether they’re a genuine cause of the disorder.
[1]https://www.washingtonpost.com/news/business/wp/2016/10/31/look-how-muc…
[2]Richards G & Smith A (2015) Caffeine consumption and self-assessed stress, anxiety, and depression in secondary school children. Journal of Psychopharmacology, 29, 1236-1247.
[3]Journalists and columnists such as Jonathan Gornall, Will Hutton, Simon Copland and Louise Chunn amongst others.
[4]Charney DS, Heninger GR & Jatlow PI (1985) Increased anxiogenic effects of caffeine in panic disorders. Archives of General Psychiatry, 42, 233-243.
[5]Forsyth JP & Karekla M (2001) Biological challenge in the assessment of anxiety disorders. In MM Antony, SM Orsillo & L Roemer (Eds) Practitioner’s guide to empirically based measures of anxiety. Springer.
[6]Kim JE, Dager SR & Lyoo K (2012) The role of the amygdala in the pathophysiology of panic disorder: Evidence from neuroimaging studies. Biology of Mood & Anxiety Disorders, http://www.biolmoodanxietydisord.com/content/2/1/20
[7]Redmond, D.E. (1977). Alterations to the function of the nucleus locus coeruleus: A possible model for studies of anxiety. In I. Hanin & E. Usdin (Eds.) Animal models in psychiatry and neurology. New York: Pergamon Press.
