Psychotropic drugs, which are sometimes called psychoactive drugs, affect the central nervous system and can cause a variety of changes in behavior or perception. Many people think psychotropic drugs are only of the illegal variety, such as lysergic acid diethylamide (LSD), angel dust and marijuana, but even something as relatively benign as caffeine is considered one of many psychotropic drugs. These drugs have various uses and can be divided into four major groups: hallucinogens, antipsychotics, depressants and stimulants. Some drugs fit into multiple categories because they produce more than one type of effect. Marijuana, for example, is considered a depressant, stimulant and hallucinogen.
One psychotropic drug that is often used is alcohol, a depressant. It can impair mood, causing either elation or depression, and it impairs the ability to think clearly or make rational decisions. Supporters for legalization of marijuana in certain countries often point to the legality of alcohol, which is considered more toxic, more addictive and potentially more impairing and dangerous.
Marijuana has many applications in medicine and might be helpful to some patients who have acquired immune deficiency syndrome (AIDS) or cancer. This drug can control nausea, promote appetite and reduce pain, so it can be helpful for people who are experiencing intense suffering. The stigma associated with illegal marijuana use has stalled its legalization or limited access to the drug for medicinal purposes in many places.
Other psychotropic drugs that affect the user's mood include antidepressants, antipsychotics, mood stabilizers and tranquilizers, which are considered vital to the practice of psychiatry. Certain antidepressants might help reduce depression or anxiety, but they also might provoke anxiety if they also are stimulants. Tranquilizers, which are depressants, might be more effective for severe anxiety. Mood stabilizers might be either stimulants or antipsychotics and can help people with bipolar conditions. Antipsychotics are often used to treat schizophrenia.
Some psychotropic drugs can foster addiction, with many of these belonging to either the stimulant or depressant classes. For example, many depressants, such as morphine, are used to alleviate symptoms of pain. Morphine is addictive and is derived from opium, from which heroin also is derived. Many people who receive morphine note hallucinatory episodes when given high doses of morphine, and long-term use of morphine can cause difficulties in withdrawing from the medication.
Stimulants, which can range from caffeine to illegal drugs such as crystal meth and cocaine, also can be addictive. For example, coffee drinkers might notice extreme headaches if they skip a day of drinking coffee. Nicotine is a highly addictive stimulant, although many people believe that it has a relaxing effect. Addiction to cocaine is almost assured after consistent use over several weeks. Children who take methylphenidate, a drug that is commonly given under certain brand names to treat attention deficit hyperactivity disorder (ADHD), can become dependent upon the medication and have a difficult time being weaned from it as adults.
The action of psychotropic drugs is not always clearly understood. For example, researchers assume that some antidepressants increase the levels of serotonin in the brain, but this has not been proved, and little explanation exists for those who have opposite reactions to medications that are used to elevate mood. In addition, nicotine is thought to both relax and stimulate, another unclear reaction.