psychopharmacology, the goal is to use drugs to improve brain function. This takes place via very specific actions within the brain. The drug may be administered in one of several ways, and its metabolism will vary based on many factors, making psychopharmacology a complicated medical issue. In addition, some people abuse substances known to have a psychopharmalogical effect. Both the appropriate and inappropriate use of these drugs can have a profound effect on both mind and body.
While researchers have described many uses for these medications, they are not yet "magic bullets" that can be aimed precisely, giving only the desired effect, doing that well, and causing no side effects (Hamilton & Timmons, 1994). Sometimes the side effects can be managed well, but sometimes a medication will help solve another (say, depression) and yet cause or aggravate another (for example, anxiety) (Hamilton & Timmons, 1994).
One author suggests that one think about the interaction of brain, environment and behavior as a triangle, with each side having an effect on the other two (Hamilton & Timmons, 1994). For instance, some drugs may have an immediate effect on behavior; a long-range effect on neurons; and the person's changed behavior may change his or her personal environment. It is important to keep all these ongoing interactions in mind to talk about pharmacology accurately.
In addition, drugs can have physical as well as behavioral or emotional effects. For instance, amphetamines will raise blood pressure, cause the pupils of the eyes to dilate, and relax smooth muscles of the intestines (Murray, 1998). They also depress appetite. The entire person must be considered when thinking about psychotropic medications.
Psychotropic drugs and the brain
The human nervous system has very specific cells that allow the nervous system to communicate within themselves. "Interneurons" exist only in the brain and spinal cord and receive signals from the rest of the body from sensory neurons as well as from other interneurons. There may be as many as 100 billion interneurons, with up to 1,000 synapses where other neurons can communicate with them (Kimball, 2003). There are many different kinds of interneurons.
Most neurons communicate by releasing neurotransmitters to another cell. The part of the cell that sends the message is called an axon. It does not directly touch another cell's synapses, but sends out a neurotransmitter. Different synapses are configured to receive different neurotransmitters (Hamilton & Timmons, 1994). The space between the axon of one cell and the synapse of the next is sometimes called the synaptic cleft, and the goal of many psychotropic drugs is to affect this process in one of several ways.
Some synapses act to reduce the effect of neurotransmitters, so the action between cells is actually far more complex than one cell sending a "message" to another. Some set off chain events, where a neurotransmitter causes a change to happen at another point so another neurotransmitter can be received (Kimball, 2003). Some neurotransmitters facilitate messages in muscles, or other parts of the body, so medications that affect neurotransmitter function can have body-wide effects. Other neurotransmitters, such as dopamine and serotonin, are found only in the brain. To complicate things further, some chemicals called peptides may serve as neurotransmitters, and some also act as hormones. The brain is a complex chemical soup and it is not easy to change those chemicals in highly controlled ways with no negative side effects (Kimball, 2003).
Once a neurotransmitter has been used, it has to be deactivated. Some are simply transported away, but some are broken down by enzymes. At any point in all of these complex operations, a psychoactive drug can alter action and change behavior, emotion, or even thought.
Central Nervous System Depressants
It is believed that CNS depressant affect the neurotransmitters serotonin or GABA (Hamilton & Timmons, 1994). Sedatives, which cause sleep, include ethanol (ethyl alcohol, the alcohol in alcoholic beverages); barbiturates, such as Phenobarbital and Seconal; and opiates.
Although many people don't think of it as a drug, ethyl alcohol is by far the most widely used psychoactive drug, and one of the few (along with nicotine and caffeine) that can be bought legally and/or without a prescription. While ethyl alcohol's ultimate effect on the CNS is as a sedative, in small amounts it can reduce anxiety or provide a feeling of euphoria (Kimball, 2003). In larger amounts, however, it depresses multiple grain functions including coordination and balance. When severely over used, it can depress the reticular formation (Kimball, 2003) and cause unconsciousness.
Inhalants are hydrocarbons. Ether and chloroform are two examples, but rarely used any more. Substance abusers sometimes inhale paint fumes or other petroleum products to get high from inhaled hydrocarbons.
Barbiturates, while addictive, can be used as sleeping pills and sometimes suppress seizures. Overused, however, they can interfere with breathing and cause death. They are particularly dangerous when combined with alcohol (Kimball, 2003), and the combination has been the cause of death in both accidents and suicides. The combination is a frequent cause of suicide, both accidental and planned. Barbiturates bind to a subset of GABA receptors designated GABAA receptors (Kimball, 2003).
Opiates are drugs derived from the opium poppy and other drugs with similar properties and include heroin, morphine, codeine and methadone. Of those drugs, heroin has no proven medical use.
Opiates, sometimes called opioids, work by depressing the nerve pathways that communicate pain, which makes them valuable when strong painkillers are needed. They can also depress other body functions, and can be used to control coughing. Codeine in particular is often used in prescription cough medicines (Kimball, 2003).
The very serious problem with opiates is that they are highly addictive. They can quickly induce dependence in the user, with tolerance, meaning that the user has to take more to get the desired effect. Heroin is the most effective painkiller of all of the opiates, but it is also the most rapidly addictive that it is unsuitable as a painkiller. Methadone is a synthetic form of opiate. While it can break the addiction to heroin, it is replaced by addiction to methadone, the difference being that an addicted person can get methadone legally so they will not have to seek out an illegal drug.
While there are less addictive painkillers, they are also less effective, and when a person is faced with severe, intractable pain, such as some cancer patients experience, or for short periods after some surgery, opiates can have a valuable place in medical care (Kimball, 2003). Opiate drugs are interesting also because they illustrate the link between centuries-old herbal medicines and the pharmaceutically-produced drugs of today. The opium poppy has been used (medicinally) and abused (recreationally) for thousands of years.
Central Nervous System Stimulants
CNS stimulants include both legal and illegal drugs. Amphetamines and amphetamine-like drugs can be prescribed (Murray, 1998). Cocaine, made from coca leaves, has very narrow medical uses and is frequently available as an illegal street drug. Other stimulants include caffeine and nicotine, and substances containing them can be legally purchased in any store selling tobacco products, coffee, etc.
Methamphetamine is a powder with a bitter taste but no odor (Murray, 1998). When produced illegally, it is often white to yellowish. As an illegal drug it is sometimes called crystal meth or speed. Legally it is sold in pill or capsule form. Illegally, it can be sold in capsules or in chunks. In addition to taking it orally, it can be used intravenously or even smoked. Once a person has become dependent on methamphetamine, it can be a difficult habit to break, with frequent relapses (Murray, 1998).
Amphetamines affect the brain in two ways. First, it stimulates (hence the name "stimulant") the areas of the brain involved in wakefulness and mood, which can create a sense of heightened alertness and well being; and second, it depresses appetite. It produces heightened alertness by releasing stored energy, one reason why using high amounts can be dangerous (Murray, 1998). Abuse of amphetamines can stimulate the brain so much that they cause delusions or even hallucinations.
Cocaine comes from the leaves of the coca plant, which is raised by some groups of people in the Andes Mountains of South America. It is legitimately used as a local anesthetic in such drugs as Novocain, but it is also widely abused as a street drug.
Hallucinogenic, or psychedelic drugs, are drugs that disrupt perception, particularly sight and sound. They frequently come from naturally occurring plants and have no medicinal qualities. Common hallucinogenic drugs include mescaline, peyote, which comes from a specific cactus plant, and lysergic acid diethylamide (LSD), an easily made synthetic chemical. Some of these drugs are used in native religious ceremonies. For instance, some Native Americans use peyote, a dried cactus flower, in religious rites.
Other psychedelic drugs include dimethoxymethylamphetamine (DOM or "STP") and methylenedioxymethamphetamine (MDMA or "ecstasy"). Their structure resembles that of serotonin, and it is believed that they bind to serotonin receptors in the brain. Phencyclidine, or PCP, sometimes called "angel dust" on the…