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In 1974, Dr. John Greden, who at that time was the Director of Psychiatric Research at the Walter Reed Army Medical Center, reported on three cases of caffeine intoxication (then called caffeinism; Figure 1) that had recently come to his attention. Because many of the symptoms of caffeine intoxication bear close resemblance to those seen in anxiety disorders, one of Greden’s goals was to alert physicians to this similarity when they encounter patients with the relevant symptoms. Here we summarize one of the three cases described in Greden (1974).
Figure 1 (© zirconicusso/Shutterstock.com)
The patient was a 37-year-old lieutenant colonel who was referred to the hospital’s outpatient psychiatric clinic with a 2-year history of “chronic anxiety.” Nearly every day, the patient experienced various distressing symptoms including restlessness, dizziness, trembling, anxiety over his professional performance, a nervous stomach, diarrhea, and insomnia. When tested, he had a high score on the Hamilton Anxiety Scale. The patient could not account for his recurring symptoms except that the symptoms worsened when he was assigned a new, highly demanding boss. Several standard medical examinations failed to identify a cause; however, questioning by the psychiatrist revealed that the patient daily consumed 8 to 14 cups of coffee along with three to four caffeinated soft drinks. On many evenings he additionally drank a cup of hot cocoa, which contains theobromine, a chemical similar to caffeine. Total caffeine intake was estimated to be 1.2 g per day. Upon receiving this information, the physician informed the patient that he might be suffering from caffeine intoxication. This suggestion was initially rejected, the patient continued his excessive caffeine intake, and the symptoms persisted. Finally, he relented and managed to reduce his caffeine consumption with a significant (though not complete) amelioration of symptoms, including lower Hamilton Anxiety Scale scores. To confirm the causal relationship between caffeine and the patient’s symptoms, the physician ordered a “challenge test” in which the patient received large doses of caffeine for several consecutive days. The symptoms predictably worsened until the challenge test ended.
As noted by Greden (1974), a syndrome associated with excessive caffeine consumption has been known at least since the early twentieth century and possibly earlier. Cases are known in which doctors had difficulty making a diagnosis or made the incorrect diagnosis of an anxiety disorder because they were unaware of the patient’s caffeine consumption. Thus, any unusual cluster of symptoms that “could” be related to dietary practices should be investigated properly through patient interview to determine whether any such practice is the causal agent producing the symptom cluster.
Reference
Greden, J. F. (1974). Anxiety or caffeinism: A diagnostic dilemma. Am. J. Psychiatry, 131, 1089–1092.