Stimulants

In addition to stimulating the central nervous system, most stimulants also increase the activity of the sympathetic nervous system, and some may produce a sense of euphoria in many individuals. Stimulants are used therapeutically to increase or maintain alertness, either to counteract normal fatigue in situations where sleep is not practical (e.g. while operating vehicles) or to counteract abnormal states that diminish alertness or interfere with consciousness in the absence of fatigue drugs to increase alertness (such as narcolepsy). They may also be used and sometimes abused to boost endurance and productivity as well as to suppress appetite. The euphoria produced by some stimulants leads to their recreational use, although this is illegal in some jurisdictions.