or more signs or symptoms th at develop during or shortly after caffeine use (Criteria A
and B). Symptoms include restlessness, nervousness, excitement, insomnia, flushed face,
diuresis, and gastrointestinal complaints, which can occur with low doses (e.g., 200 mg) in
vulnerable individuals such as children, the el derly, or individuals who have not been ex-
posed to caffeine previously. Symptoms that ge nerally appear at levels of more than 1 g/
day include muscle twitching, rambling flow of thought and speech, tachycardia or car-
diac arrhythmia, periods of inexhaustibility, and psychomotor agitation. Caffeine intoxi-
cation may not occur despite high caffeine inta ke because of the development of tolerance.
The signs or symptoms must cause clinically significant distress or impairment in social,
occupational, or other importan t areas of functioning (Criterion C). The signs or symp-
toms must not be attr ibutable to another medical condit ion and are not better explained by
another mental disorder (e.g., an anxiety disorder) or intoxi cation with another substance
(Criterion D).
Associated Features Supporting Diagnosis
Mild sensory disturbances (e.g., ringing in the ears and flashes of light) may occur with high
doses of caffeine. Although large doses of caffeine can increase heart rate, smaller doses can
slow heart rate. Whether excess caffeine intake can cause headaches is unclear. On physical
examination, agitation, restlessness, sweati ng, tachycardia, flushed face, and increased
bowel motility may be seen. Caffeine blood levels may provide important information for
diagnosis, particularly when the individual is a poor historian, although these levels are not
diagnostic by themselves in view of the individual variation in response to caffeine.