Stimulants (also referred to as psychostimulants) is an overarching term that covers many drugs including those that increase activity of the body, drugs that are pleasurable and invigorating, or drugs that have sympathomimetic effects. Due to their rendering a characteristic “up” feeling, stimulants are also occasionally referred to as “uppers”. Depressants or “downers”, which decrease mental and/or physical function, are in stark contrast to stimulants and are considered to be the functionally opposite drug class.
Stimulants are widely used throughout the world as prescription medicines as well as without a prescription (either legally or illicitly) as performance-enhancing or recreational drugs. The most frequently prescribed stimulants as of 2013 were lisdexamfetamine, methylphenidate, and amphetamine. It is estimated that the percent of the population that has abused amphetamines, cocaine and MDMA combined is between .8% and 2.1%.
Stimulants are substances that induce a number of characteristic symptoms. CNS effects include alertness with increased vigilance, a sense of well-being, and euphoria. Many users experience insomnia and anorexia, and some may develop psychotic symptoms. Stimulants have peripheral cardiovascular activity, including increased blood pressure and heart rate. They encompass a broad category of substances, including those prescribed for medical conditions; those manufactured for illicit substance abuse; and those found in over-the-counter (OTC) decongestants, herbal extracts, caffeinated beverages, and cigarettes.
Stimulants, sometimes called “uppers,” temporarily increase alertness and energy. The most commonly used street drugs that fall into this category are cocaine and amphetamines.
Prescription stimulants come in tablets or capsules. When abused, they are swallowed, injected in liquid form or crushed and snorted.
Stimulants are drugs that make you feel more alert. Caffeine, found in tea, coffee and chocolate, is one example. Many plants contain naturally occurring stimulants (probably to deter invading insects) that in humans make the brain and body more active. Many stimulants, such as nicotine and cocaine, are harmful and addictive. Amphetamine, which was first made a century ago, is another well-known stimulant.
The short-term effects of stimulants include exhaustion, apathy and depression—the “down” that follows the “up.” It is this immediate and lasting exhaustion that quickly leads the stimulant user to want the drug again. Soon he is not trying to get “high,” he is only trying to get “well”—to feel any energy at all.
Stimulants can be addictive. Repeated high doses of some stimulants over a short period can lead to feelings of hostility or paranoia. Such doses may also result in dangerously high body temperatures and an irregular heartbeat.
Stimulants in therapeutic doses, such as those given to patients with ADHD, increases ability to focus, vigor, sociability, libido and may elevate mood. However, in higher doses stimulants may actually decrease the ability to focus, a principle of the Yerkes-Dodson Law. In higher doses stimulants may also produce euphoria, vigor, and decrease need for sleep. Many, but not all, stimulants have ergogenic effects. Drugs such as ephedrine, pseudoephedrine, amphetamine and methylphenidate have well documented ergogenic effects, while drugs such as cocaine and methamphetamine have the opposite effect.Neurocognitive enhancing effects of stimulants, specifically modafinil, amphetamine and methylphenidate have been documented in healthy adolescents, and is a commonly cited reason among illicit drug users for use, particularly among college students in the context of studying.
In some cases psychiatric phenomenon may emerge such as stimulant psychosis, paranoia, and suicidal ideation. Acute toxicity has been reportedly associated with a homicide, paranoia, aggressive behavior, motor dysfunction, and punding. The violent and aggressive behavior associated with acute stimulant toxicity may partially be driven by paranoia. Most drugs classified as stimulants are sympathomimetics, that is they stimulate the sympathetic branch of the autonomic nervous system. This leads to effects such as mydriasis, increased heart rate, blood pressure, respiratory rate and body temperature. When these changes become pathological, they are called arrhythmia, hypertension, and hyperthermia, and may lead to rhabdomyolysis, stroke, cardiac arrest, or seizures. However given the complexity of the mechanisms that underly these potentially fatal outcomes of acute stimulant toxicity, it is impossible to determine what dose may be lethal.
As the name suggests, stimulants increase alertness, attention, and energy, as well as elevate blood pressure, heart rate, and respiration. Stimulants historically were used to treat asthma and other respiratory problems, obesity, neurological disorders, and a variety of other ailments. But as their potential for abuse and addiction became apparent, the medical use of stimulants began to wane. Now, stimulants are prescribed to treat only a few health conditions, including ADHD, narcolepsy, and occasionally depression—in those who have not responded to other treatments.