David Cohen, M.D.·Published 27 September 2008·9 min read
Key points
Stimulant drugs, or "uppers," include cocaine and the amphetamines.
These drugs are available as over-the-counter decongestants, diet aids, and stimulants.
Nicotine is included in this section since it has some stimulant properties and closely resembles the stimulants with respect to withdrawal symptoms and associated cravings.
All of the stimulants act in one way or another to increase the activity of a part of the central nervous system known as the sympathetic nervous system, which is what causes us to be on alert and produces the fight or flight reaction.
Stimulant drugs, or "uppers," include cocaine and the amphetamines. Substances such as ephedrine, pseudoephedrine, and phenylpropanoloamine are also classified as stimulants.
These drugs are available as over-the-counter decongestants, diet aids, and stimulants. Caffeine, found in coffee, tea, colas, cocoa, and over-the-counter drugs, is also a stimulant.
Nicotine is included in this section since it has some stimulant properties and closely resembles the stimulants with respect to withdrawal symptoms and associated cravings.
All of the stimulants act in one way or another to increase the activity of a part of the central nervous system known as the sympathetic nervous system, which is what causes us to be on alert and produces the fight or flight reaction. It functions in a balanced fashion with the parasympathetic nervous system, which controls functions such as eating, digesting, and slowing the heart rate. Norepinephrine, which is closely related to adrenaline, is the main neurotransmitter involved in the activity of the sympathetic nervous system.
When your sympathetic nervous system is active, several things occur. Blood vessels in the gut constrict, leading to a reduced appetite. Blood flow to the brain and muscles increases. Your heart rate goes up, as does your blood pressure.
Pupils dilate, and in extreme cases your hair stands on end.
Your senses become more acute, and you are more alert. Your ability to concentrate goes up. To a mild degree, these effects are pleasurable to most people.
Caffeine, nicotine, and over-the-counter preparations produce these effects to a mild degree if they're used in moderation. Cocaine and amphetamines are much more potent, and have much more potential for abuse. The use of intravenous or smoked forms of stimulants leads to an intense and highly addictive sensation and also to the development of cravings when the drug is stopped.
Stimulant addicts typically use in an episodic fashion. The user will binge for several days (periods called runs) and then crash. During the crash, the user will experience depression, fatigue, agitation, and craving. Cocaine or amphetamine addicts will often abuse depressant drugs, opiates, or alcohol during the crash to modulate the symptoms.
Cocaine Cocaine is found naturally in the leaves of the coca plant, which grows in high altitude areas of South America. The ancient Incas chewed these leaves for their mild stimulant effect, which resembles that of a strong cup of coffee. The practice is still in effect.
The amount of drug that is delivered in this fashion is rather low, and it does not pose a major health problem. But distilling the active ingredient - cocaine - from the coca plant produces a much more potent substance.
Written and revised by
David Cohen, M.D.
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Processed cocaine has been used for at least a century, for a variety of purposes.
When applied to tissue, cocaine produces local anesthesia.
A legitimate use of cocaine is found in the operating room.
Cocaine spray is applied before the insertion of breathing tubes used during surgery. Cocaine's stimulant effects have also been long recognized. Sigmund Freud had advocated the use of cocaine for a variety of medical indications before coming to understand the drug's addictive potential and retracting any such recommendations.
Cocaine acts directly on brain cells within the pleasure center by stimulating the release of dopamine and other neurotransmitters. It essentially overrides the natural control mechanisms of this system, which leads to the intensely pleasurable high but also to an eventual depletion of the stores of these chemicals. Cocaine users eventually lose the ability to feel this pleasurable sensation as the stores are depleted further and further and the brain becomes tolerant to the drug's effects.
But the drug also sets up a strong conditioning effect leading to severe cravings. Within a short period of time, the user is caught between the strength of the cravings and the dull depression that results when the drug is not present in the system. It can take many months for the brain to build the stores of neurotransmitters back up. Irritability, severe depression, hallucinations, and delusions can result from the chronic use of cocaine. Sudden mood swings and episodes of uncharacteristic hostility and abusiveness may be observed by family members and coworkers who may be unaware of the addiction.
Cocaine is abused in several forms. Powder cocaine is inhaled nasally. The substance can be altered chemically through a process of free-basing and administered intravenously or by inhalation. Crack or rock cocaine is formed from powder cocaine, and comes in small crystals that resemble chunks of soap. These are burned in a pipe or another vehicle and inhaled. One crack rock can be relatively inexpensive, making them widely accessible, but it's not uncommon for a crack addict to spend as much money as is available - and more - to repeat the brief high over and over again.
It has been something of a rule of thumb that most addicts have a particular drug of choice, or a category of choice. For example, people who do "downers" generally don't like the effects of stimulants and vice versa. However, crack cocaine has proven to be the great leveler in this regard - when crack cocaine is available, many addicts of all types eventually end up using it primarily, while occasionally drinking or using other drugs such as the depressants to deal with side effects.{pagebreak}
Amphetamines The amphetamines include legitimate pharmaceutical preparations as well as illicitly produced substances. Amphetamines have been used medically as bronchodilators for asthma, appetite depressants for weight loss, in treatment of attention deficit disorder in children and of narcolepsy, and as a supplement in the treatment of some forms of resistant depression. During World War II and the Vietnam war, amphetamines were made available to troops to help counteract fatigue and improve concentration.
During the 1960s and 1970s, the illicit use of amphetamines became widespread. A large proportion of the drugs came from the diversion of legitimately produced pharmaceutical preparations. As a result of increased regulatory efforts, it is less common now to find drugs such as Dexedrine or Benzedrine on the streets. Instead, the supply of crystal methamphetamine produced in illegal labs has grown. "Cooking" crystal meth is relatively easy and quite lucrative, although it is extremely dangerous. The chemicals used to create the drug are toxic and highly explosive. Crystal meth addiction tends to cluster in certain parts of the country, such as the South and the Southwest, close to the illicit labs. It's also frequently abused by long-haul truckers. In some cases, crack cocaine addicts have turned to crystal meth as a substitute because of the lower cost and longer high.
Amphetamines exert their effect on the brain in a twofold fashion. They attach to and directly stimulate the cells that oduce excitation of certain areas of the brain. They also cause these cells to secrete neurotransmitters like norepinephine and dopamine, which also contribute to the stimulating and euphoric effects. The main problem with the amphetamines is that, in overriding the brain's normal regulatory mechanisms, they cause profound depletion of the brain's normal chemicals, just as cocaine does. Even months after cessation of use, lab animals demonstrate lower than normal levels of important neurotransmitters like norepinephrine, dopamine, and serotonin. It is thought that in some cases of long-term, heavy use, these chemicals never return to normal levels.
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Long-term, heavy use of amphetamines leads to a psychosis that is clinically indistinguishable from paranoid schizophrenia. "Speed freaks" become intensely paranoid, and may experience hallucinations. Amphetamines also trigger seriously aggressive behavior, especially if the user feels threatened.
Physical effects of the stimulant properties of amphetamines can lead to major physical complications such as heart damage, strokes, and life-threatening fevers.
Amphetamines are similar to other stimulant drugs in how they produce addiction. There is a powerful conditioning effect. The brain learns to associate a pleasurable sensation with all kinds of cues connected to the use of the drug. During the early period of abstinence, as with cocaine, the addict has to deal with powerful cravings that are a result of this learning process.{pagebreak}
Caffeine Caffeine is probably the most widely used mood-altering substance. It is found in coffee, tea, cola, cocoa, and over-the- counter analgesics and stimulants. It's not associated with any kind of social or serious health problem and is therefore not considered dangerous enough to regulate. It does, however, have some troublesome effects that are worth knowing about.
The term "caffeinism" refers to a group of symptoms caused by excessive, chronic ingestion of the substance, including restlessness, nervousness, and muscle twitching, as well as some gastrointestinal problems. It's a common cause of insomnia or restless sleep. For people with depression or anxiety disorders, caffeine can aggravate symptoms and complicate treatment.
Withdrawal symptoms begin to emerge and peak within a day or two after the last ingestion of caffeine. These symptoms can include fatigue, headache, irritability, withdrawal, and poor concentration. It's not uncommon for people who drink coffee all day long during the work week to experience caffeine withdrawal on the weekends or during vacations. The easiest way to diagnose caffeine withdrawal is to have the sufferer drink a cup of coffee or a Coke and see what happens.
Weekend headache sufferers who get relief from over-the- counter preparations that contain caffeine are unwittingly treating the withdrawal.
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Nicotine Addiction to nicotine is probably the most prevalent drug problem in today's world. Nicotine is found in tobacco products such as cigarettes, cigars, pipe tobacco, chewing tobacco, and snuff. The addictiveness of nicotine is well documented, as are the health hazards of smoking and chewing tobacco.
Nicotine acts as a stimulant in a fashion similar to that of cocaine and amphetamines; however, its overall effect is less pronounced. It also interacts with a number of other systems in the brain such as the cholinergic system and hormonal systems. It has reinforcing properties caused by its interaction with dopamine-producing cells in the pleasure center of the brain.
Smokers have been shown to unconsciously regulate their doses of nicotine to amazingly consistent levels. Even smokers who switch to "light" cigarettes eventually increase the number of cigarettes smoked or the depth of inhalation to keep the nicotine levels constant.
Nicotine's effects are immediate and short-lived. Smokers generally begin to crave another cigarette within a few hours of the last one, and it is thought that the primary mechanism for addiction to cigarettes is that of treating the symptoms of withdrawal. In other words, the immediate reduction of anxiety and irritability that comes from smoking another cigarette tends to reinforce the addiction.
Although nicotine addiction does not cause the profound social and behavioral problems that result from the use of drugs like cocaine and amphetamines, it is associated with many serious medical problems, including cancer and heart disease. Quitting smoking is no easy matter, and there are high failure rates for all methods. Nonetheless, social pressure has encouraged many people to be successful in their efforts. It may be that as smoking becomes more and more socially unacceptable, the remaining smokers will be people with more complicated problems. For example, smoking is more prevalent among people who are addicted to other substances and among those with other psychiatric problems.
The reasons for this are not completely clear, but it's probably because the brain is so complicated and nicotine's effects are fairly widespread throughout the nervous system. Changing the system by eliminating nicotine may cause a cascade of effects in people whose brains are otherwise abnormal, which would make quitting much more complicated.{pagebreak}
Over-the-Counter Stimulants A number of fairly powerful stimulants are available on the shelves of the drugstore and health food store. Among these are ephedrine and pseudoephedrine preparations and the compound phenylpropanolamine, which is commonly found in over-the-counter diet aids. These preparations are relatively safe if used as directed, but are often misused. Ephedrine and related compounds closely resemble amphetamines in chemical structure. Recent research has confirmed the ability of ephedrine to produce the same lever-pushing behavior that is seen in lab animals exposed to other addictive drugs.
Primary addictions to over-the-counter stimulants are uncommon but may be more prevalent than we know, since these drugs are not regulated and often doctors do not ask about them when taking medical histories. It is important that people who are recovering from addictions know that these compounds may trigger relapse or cause a problem with cross-addiction.
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