Caffeine is a natural central nervous system stimulant usually found in tea, coffee, and several other beverages. It is arguably the most widely consumed psychoactive substance in the world. Though establishing the cognitive consequences of caffeine consumption has been challenging, a great deal of research has been carried out in favor of the enhancer effects of caffeine over its hazardous effect.
Cognitive function is a broad term that refers to the mental processes involved in the acquisition of knowledge, manipulation of information, and reasoning. Humans enjoy the flavor and stimulating effect of a cup of coffee that contains methylxanthine, without knowing that by doing so, they are ingesting a substance that can help improve their lives. Caffeine’s primary mechanism of action is on the adenosine receptors in the brain, it readily crosses the blood-brain barrier and acts on all four adenosine receptor subtypesA1, A2a, A2b, and A3 . Its action on adenosine receptors stimulates the release of catecholamine which causes a generalized systemic stimulatory effect, as these receptors are not limited only to the central nervous system, but are found throughout the entire body.
Consumption of caffeine has been shown to enhance mental and cognitive functions. Caffeine is known to stimulate and control different brain activities resulting in improved mental alertness, reduced fatigue and enhanced performance; which is important in athletes and low arousal situations. Caffeine’s ability to block Adenosine receptors has been observed at low doses, such as those contained in a single cup of coffee; which explains why it has been widely considered a cognitive enhancer and as a result plays an important role in a healthy life (Cappelletti et al. 2015). Moderate consumption of caffeine has been shown to reduce the risk of diseases such as Alzheimer and Parkinson’s disease, stroke, certain skin cancers, type 2 diabetes, and other illnesses, allowing consumers to lead healthy quality lives. However, copious caffeine consumption has been observed to cause toxicity and several disorders hazardous to the health and wellbeing of consumers.
Caffeine use can lead to several adverse effects that can be hazardous to health. Apart from being addictive and toxic, caffeine as with most drugs or medications have a long list of adverse effects that are associated with its use. Adverse effects of caffeine use ranging from mild to severe include anxiety, depression, insomnia, restlessness, agitation, irritation, seizure, arrhythmia, ischemia, hallucination, and psychosis. These effects are generally dependent on the amount of caffeine consumed and the individual’s sensitivity to the drug. Both adults and adolescents who consume high doses of caffeine frequently report psychiatric symptoms and disorders, mainly anxiety, mood disorders, and also behavioral alterations.
Caffeine users can also suffer from withdrawal symptoms. If addicted users try to stop abruptly rather than tapering off they develop symptoms similar to those seen in drug abusers. These symptoms range from headache and fatigue to depression, irritability, and difficulty concentrating; leading from mild to clinically significant distress or impairment in daily function. Such withdrawal effects pose a serious health risk as it endangers the lives of caffeine consumers especially those who have become addicted.
Caffeine should be considered as an enhancer and not a danger to people’s health. This is because when taken in little and moderate quantities, caffeine possesses several nutritional values which impact positively on human health and cognitive function. Caffeine only becomes a health challenge when taken in large amounts beyond the capacity of the body to metabolize it, leading to several adverse effects and toxicity.
