Caffeine Intoxication

• Caffeine is the most widely used psychoactive substance in the world.
  • In North America, more than 80% of adults regularly consume caffeine, most typically in the form of including tea, coffee, caffeinated soda, “energy” drinks, over-the-counter analgesics, cold remedies, weight-loss aids, and chocolate.^[3]
• The prevalence of caffeine intoxication is unclear.
  • In the United States, about 7% of the population may experience symptoms and functional impairment consistent with a diagnosis of caffeine intoxication.^[4]

• The half-life of caffeine of is 4 to 6 hours, and intoxication symptoms usually resolve within 24 hours
• There are no known long-lasting consequences from caffeine intoxication.
  • However, individuals who consume extremely high doses of caffeine (>5 to 10 grams) may require immediate medical attention, as these doses can be lethal (grand mal seizures and respiratory failure).^[5]
  • During the period of intoxication, there can be interference with sleep (insomnia) or feelings of hyperarousal.

• Excessive caffeine use is associated with depressive disorders, psychotic disorders, sleep disorders, bipolar disorders, eating disorders, and substance-related disorders.
  • Individuals with anxiety disorders are more likely to avoid caffeine use, and have lower risk for caffeine intoxication.

• Oral contraceptives significantly decrease the elimination of caffeine (via CYP 1A2 inhibition) and consequently may increase the risk of intoxication.^[6]

Recent consumption of caffeine (typically a high dose, >250mg)

At least 5 of the following signs or symptoms developing during, or shortly after caffeine use:

1. Restlessness
2. Nervousness
3. Excitement
4. Insomnia
5. Flushed face
6. Diuresis
7. Gastrointestinal disturbance
8. Muscle twitching
9. Rambling flow of thought and speech
10. Tachycardia or cardiac arrhythmia
11. Periods of inexhaustibility
12. Psychomotor agitation

The signs or symptoms in Criterion B cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.

The signs or symptoms are not attributable to another medical condition and are not better explained by another mental disorder, including intoxication with another substance.

• Palpitations, agitation, tremor, insomnia are common signs of caffeine intoxication.
• Other symptoms can include restlessness, nervousness, excitement, insomnia, flushed face, diuresis, and gastrointestinal complaints, which can occur with low doses (<200mg) in children, the elderly, or caffeine-naive individuals.^[7]
• Sensory disturbances (e.g. - ringing in the ears and flashes of light) can occur with high doses of caffeine.

• Other mental disorders
  • Caffeine intoxication symptoms (e.g. - panic attacks) can resemble primary mental disorders. To meet criteria for caffeine intoxication, the symptoms must not be better explained by another medical condition or mental disorder (e.g. - anxiety disorder)
• Other caffeine-induced disorders
  • Caffeine intoxication is different from caffeine-induced disorders such as caffeine-induced anxiety disorder, by the fact that the symptoms in these latter disorders are in excess of what is expected with caffeine intoxication and are longer lasting beyond the period of intoxication.