Caffeine

Caffeine really works in two ways. It is an inhibitor as well as a stimulant. In a normal brain, a chemical called adenosine builds up. This is a chemical that makes a person sleepy. However, in a brain that contains caffeine, the caffeine binds to the adenosine receptors. Thus, the adenosine is inhibited and there is no buildup of this chemical. Also, caffeine triggers the brain to release another chemical called dopamine. Dopamine is released in the part of the brain that feels pleasure, so many people feel happy after ingesting caffeine. Caffeine is an antagonist because it inhibits the adenosine from building up on the neurons. Caffeine, however, is also an agonist because it causes the neurons to release dopamine, a chemical not usually produced in high concentrations.

Over the long term, there really aren't very many side effects for caffeine unless more than 650 mg a day are ingested. For perspective, this is between eight and nine cups of coffee per day. However, if enough caffeine is ingested the long term effects could be as follows: chronic insomnia, stomach ulcers, and anxiety and depression. Also, there is some evidence that caffeine may be related to an irregular heartbeat and to higher cholesterol, but there is no conclusive evidence relating caffeine to heart disease.

There are not many ways to misuse caffeine. If used too much for too long one can experience headaches associated with caffeine withdrawal if there is a sudden decrease in the amount of caffeine ingested. Also, caffeine may be harmful during pregnancy. Ingestion of large amounts of caffeine during pregnancy has been associated with low birth weight and miscarriages.

Really though, there is no evidence that caffeine creates dependence. However, it can cause insomnia and other problems, so use should be limited. The best way to do this is to gradually decrease the intake of caffeine and replace it with decaffeinated alternatives.