substance-related disorder caffeine intoxication - Restlessness - Nervousness - Excitement - Insomnia - Flushed face - Diuresis - Gastrointestinal disturbance - Muscle twitching - Rambling flow of thought and speech - Tachycardia or cardiac arrhythmia - Periods of inexhaustibility - Psychomot agitation The essential feature of caffeine intoxication is recent consumption of caffeine and five or more symptoms that develop during, or shortly after caffeine use. DSM-IV-TR caffeinism 305.90