According to the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5),excessive caffeine intake can lead to a condition known as “caffeine intoxication” although it’s not the sort of intoxication we think of when we hear that word.
If you have more than 250 mg of caffeine (typically two to three cups of brewed coffee) and experience five or more of the following symptoms, you’ve probably been caffeine-buzzed, according to the guide: restlessness, nervousness, excitement, insomnia, muscle twitching, rambling flow of thought and speech. flushed face, diuresis, gastrointestinal disturbance, tachycardia or cardiac arrhythmia.
The disorder falls under the heading “Caffeine Related Disorders”, which features a new entry in DSM-5: caffeine withdrawal. Symptoms include fatigue, headache and difficulty focusing.
Thankfully, the effects are a normal response and are just transitory.