Caffeine is a widely consumed psychoactive drug, found naturally in coffee, tea, and other food sources. It is the most widely consumed psychoactive substance in the world, with an estimated 90% of adults in North America consuming it regularly (Thompson & Manore, 2015). Caffeine acts as a stimulant, increasing alertness, energy, and concentration. It has been associated with improved cognitive performance, particularly in tasks requiring vigilance, reaction time, and memory (Gardner et al., 2017).

Caffeine is absorbed relatively quickly, reaching peak levels in the bloodstream within 30-60 minutes of ingestion (Gardner et al., 2017). Its effects last several hours, with most of the drug eliminated from the body within 6-10 hours (Gardner et al., 2017). While moderate doses of caffeine (up to 400 mg/day) are generally considered safe, larger doses can cause restlessness, anxiety, and insomnia (Gardner et al., 2017).

Beyond its well-known effects on alertness and cognition, caffeine has also been studied for its potential health benefits. Some studies have suggested that caffeine may reduce the risk of certain types of cancer, Parkinson’s disease, and Type 2 diabetes (Gardner et al., 2017). It has also been linked to improved cardiovascular health, with some evidence suggesting that caffeine consumption may reduce the risk of stroke and heart attack (Gardner et al., 2017). However, more research is needed to fully understand the effects of caffeine on health.

In conclusion, caffeine is a widely consumed psychoactive drug with both cognitive and potential health benefits. While moderate doses are generally considered safe, larger doses can cause anxiety and insomnia. Further research is needed to understand the full range of effects of caffeine.


Gardner, E., Rees, K., & Davies, B. (2017). Caffeine and health. Nutrition Bulletin, 42(1), 28-54.

Thompson, D., & Manore, M. (2015). Caffeine and physical activity. Nutrition Reviews, 73(5), 338-350.

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