Eigenpoll : Cognitive improvement : Cocaine

http://en.wikipedia.org/wiki/Cocaine

Cocaine is a powerful nervous system stimulant.

Cocaine increases alertness, feelings of well-being and euphoria, energy and motor activity, feelings of competence and sexuality. Anxiety, paranoia and restlessness can also occur, especially during the comedown. With excessive dosage, tremors, convulsions and increased body temperature are observed. Severe cardiac adverse events, particularly sudden cardiac death, become a serious risk at high doses due to cocaines blocking effect on cardiac sodium channels. Even occasional use of cocaine could cause trouble to the body and mind.

http://en.wikipedia.org/wiki/Cocaine