caffeinism

noun

caf·​fein·​ism -ˌiz-əm 

: an abnormal condition caused by the consumption of large amounts of caffeine and marked by restlessness, nervousness, irritability, insomnia, diuresis, tremors, and tachycardia

In general, more than 1.5 grams of caffeine a day can cause the typical symptoms of caffeinism: anxiety, insomnia, irritability and palpitations.

—Richard A. Friedman, The New York Times

I ran in to find her pale, in a cold sweat, with her heart racing. She had had four cups of coffee in two hours and was suffering from caffeinism.

—People Weekly