Stimulant drugs are a type of drug that speeds up messages between the brain and the body and are also legal drugs. This includes caffeine. This is why caffeine makes you feel more alert and active whenever you drink it. Caffeine specifically stimulates the central nervous system. It also increases blood pressure and increases release of stomach acid. Caffeine is not only found in coffee but can be found in tea leaves, cacao pods, kola nuts, and energy drinks such as monsters and red bulls. Caffeine effects people differently depending on their size, health, the amount of caffeine you consume, and affects you differently depending on what other drugs you may take. A couple side effects of caffeine are feeling more active, relentlessness, difficult sleeping, anxiety, dehydration, urgency for urination, and increased heartrate. Caffeine can also cause long term affects such as nervousness, muscle tremor, and low blood pressure with faintness or dizziness.
Like red bulls or any energy drink, the "come-down" after the effect of caffeine can make a person feel more sluggish and very fatigued. Although legal, like any drug, drinking caffeine over time may make it difficult to stop. This is because the body and brain become used to it being in its system to function every time. This can lead to withdraw. The symptoms would include headaches, fatigue, depressed mood, irritability, and difficult to stay concentrated.