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Depressants, also called hypnotics, sedatives, andtranquilizers, are drugs that reduce the activity level of neurons. Typical results are sluggish movement, relaxed muscles, and a sleepy state of consciousness.

Hypnotics produce an altered state, by definition. Tranquilizers may produce sleepiness alone. Both hypnotics and tranquilizers can be categorized as sedatives, because both have the effect of calming people or relaxing muscles. Alcohol is a depressant although not always categorized as a sedative.

What effects do sedatives have?

Many sedatives are potentiated by alcohol, meaning the combination of the two drugs produces an effect greater than their individual effects. A famous case history is that of Karen Ann Quinlan, who mixed alcohol and tranquilizers at a party and went into a permanent coma.

Quinlan later she became the focus of a landmark court case about the right to die. When it became clear she would never recover from her coma, her parents asked the courts for permission to turn off her respirator.

After a court fight, the respirator was unplugged. Quinlan started breathing on her own and continued to do so for nearly 10 years. Her brain damage had been caused by profound depression and oxygen loss caused by the combin­ation of alcohol and sedatives.

One of the first sedatives to be widely used was phenobarbital. In the early 20th Century it was commonly used as a general anesthetic, to keep patients unconscious during surgery. Pheno­barbital is an example of a barbiturate (a word with two pronunciations: bar-bit-TUR-ate or bar-BIT-tur-ate).

Barbiturates are still used sometimes for general anesthetic during operations, although more modern drugs such as propofol (the drug that killed Michael Jackson) have been developed. Barb­iturates are sometimes prescribed to people with epilepsy when milder drugs fail to control seizures.

In an old book or movie you may come across a reference to a Mickey Finn. In the early decades of the 1900s this referred to an alcoholic drink with barbiturates secretly added. The effect was to knock a person out, due to the potentiation between alcohol and sedatives.

What is a "Mickey Finn"?

PCP (phencyclidine) or "angel dust" is a potent tranquilizer originally devel­oped for veterinarians to use with animals. There was a time when PCP abuse was common.

PCP's effects were somewhat unpredictable. Users might have no trouble with it until suddenly having a profoundly negative reaction to it. Repeated use led to mood disorders, depression, anxiety, and occasional violent episodes.

Musician James Brown once had a bad reaction to PCP during which he led police on a multi-state car chase, ending only when they shot out the wheels on his car. Emergency Room personnel of the late 1970s dreaded the "whack attacks" in which people on PCP simply went wild.

A doctor commented, "When I hear it takes six people to hold a guy down, I know it's PCP" (Isaacs, 1978). PCP use peaked in the mid-1980s then fell sharply after laws were passed limiting the manufacture of its main ingredient. By the 1990s PCP was rarely abused.

What is PCP and what effects can it produce?

Methaqualone is a muscle relaxant. It was a commonly abused drug in the early 1980s. "Ludes" (a term derived from the brand name "Quaaludes") were cheap to manufacture and easy to conceal. Like PCP abuse, methaqualone abuse tapered off dramatically after government officials limited the manufacture of its main ingredient.

Methaqualone is often categorized as a hypnotic because it produces an altered, trance-like state of mind. In small doses it was useful for preventing muscle spasms; in larger doses it produced a numb­ing effect.

Police videos of drivers on metha­qualone showed its profound influence on motor coordination. People intox­icated on alcohol have a hard time walking a straight line; people on methaqualone sometimes could not even walk in a forward direction.

What is methaqualone? What did police films of methaqualone users reveal?



Alcohol is the most familiar drug in Western society. Although alcohol makes some people more active by reducing their inhibitions or shyness, it is a depressant in its chemical action.

A person who drinks a fifth of whiskey in one gulp can die. That amount of alcohol can depress the centers controlling respiration in the brain, causing breathing to stop.

One student belonged to a fraternity in which the birthday tradition (supposed­ly) was to drink the same number of shots of whiskey as one's age. The student was found dead the day after his birthday with the words "23 shots" written on his forehead.

His friends assumed he simply passed out after so much drinking. The anguished parents brought these details to the attention of news media in an attempt to prevent such episodes from occurring in the future.

How did a student die from alcohol on his 23rd birthday?

Alcohol is both addictive and dangerous. These characteristics are hardly news to most people. Polls consistently indicate that a third of the families in America are troubled by alcohol abuse and 80% of Americans identify alcohol abuse as a major national problem.

The late George Gallup, who started collecting poll data on these questions in the early 1980s, commented that this was an extraordinary number, because it was rare for 80% of Americans to agree about anything.

What polling result surprised Gallup?

In small doses, alcohol is an effective anxiety-reducing drug, producing a "loose" feeling that may be accompanied by relaxed social inhibitions.

Apparently one reason alcohol releases inhibitions is that most people expect it to have that effect. In a classic study, Marlatt and Rohsenhow (1981) found that people who thought they were drinking alcohol (but were not) showed the same sorts of behavior as people who actually drank.

People fooled into thinking they were drinking an alcoholic beverage reported relaxation. They showed increased willingness to talk about personal matters. Marlatt replicated the study for the NBC news program Dateline in 2000, showing the same expectancy effect worked in a new generation of students.

What sort of placebo effect did Marlatt and Rohsenhow (1981) discover?

Alcohol has distinctive effects on the thought process. Claude Steele (1990) called it alcohol myopia. This is a metaphor. Alcohol does not really make people get myopic (which means near-sighted). However, alcohol makes people–and laboratory rats–neglect long-term consequences in favor of short-term pleasures.

What is "alcohol myopia"?

This is what Steele called alcohol myopia. After alcohol consumption, long-term problems seem more remote. Immediate sens­ations are vivid.

This produces the escape some people seek. It also leads people to do foolish things that are not in their own long-term interest.

For example, experts on AIDS say alcohol is a risk factor for AIDS. People who know perfectly well how to prevent HIV transmission may neglect to do so when influenced by alcohol.


Marlatt, A. & Rohsenhow, D. (1981, December). The think-drink effect. Psychology Today, pp.60-68,93.

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