Depressants have been used by people of almost every culture to induce sleep, relieve stress, and alleviate anxiety. While alcohol is one of the oldest and most universal cure-alls used for these purposes, hundreds of substances have been developed that produce central nervous system depression. These drugs have been referred to as downers, sedatives, hypnotics, minor tranquilizers, anxiolytics, and anti-anxiety medications. Unlike most other classes of drugs of abuse, depressants are rarely produced in undercover laboratories. Generally, legitimate pharmaceutical products are sold illegally. One major exception to this is a relatively recent drug of abuse, gamma hydroxybutyric acid (GHB).
Choral hydrate and paraldehyde are two of the oldest pharmaceutical depressants still in use today. Other depressants, including gluthethimide, methaqualone, and meprobamate have been important players in the arena of depressant use and abuse. However, two major groups of depressants have dominated the legal and illegal drug market for nearly a century, first barbiturates and now benzodiazepines. We are seeing an increase in drug rehab admissions for benzodiazepines
In the first half of the 20th century, barbiturates were very popular. In moderate amounts, these drugs produce a state of intoxication, very similar to alcohol intoxication. Slurred speech, loss of motor coordination, and impaired judgment are all symptoms of barbiturates. Depending on the dose, frequency, and length of use, one can quickly develop tolerance, physical and psychological dependence to barbiturates. With the development of tolerance, the margin of safety between the effective dose and the lethal dose becomes very narrow. That is, in order to obtain the same level of intoxication, the tolerant abuser can raise his or her dose to a level that may result in coma or death. Although many individuals have taken barbiturates therapeutically without harm, concern about the barbiturate addiction and the constantly increasing number of fatalities associated with them led to the development of alternative medications. Today, less than 10 percent of all depressant prescriptions in the United States are for barbiturates.
In the 1960s, benzodiazepines started being marketed. Publicized as much safer depressants with far less addiction potential than barbiturates, today these drugs account for about one out of every five prescriptions for controlled substances. Although benzodiazepines produce significantly less respiratory depression than barbiturates, it is now recognized that benzodiazepines share many of the undesirable side effects of the barbiturates. A number of toxic central nervous system effects are seen with chronic high-dose benzodiazepine therapy, including headaches, irritability, confusion, memory impairment and depression. The risk of developing over-sedation, dizziness, and confusion increases substantially with higher doses of benzodiazepines. Prolonged use can lead to physical dependence even at doses recommended for medical treatment. Unlike barbiturates, large doses of benzodiazepines are rarely fatal unless combined with other drugs or alcohol. Although primary abuse of benzodiazepines is well documented, abuse of these drugs usually occurs as part of a pattern of multiple drug abuse. For example, heroin or cocaine abusers will use benzodiazepines and other depressants to enhance their "high" or alter the side effects associated with over-stimulation or narcotic withdrawal.
Fairly recently, GHB has emerged as a significant drug of abuse throughout the US.
Abusers of this drug fall into three major groups:
1. Users who take GHB for its MDMA-like hallucinogenic effects or as an intoxicant or euphoriant.
2. Bodybuilders who abuse GHB for its alleged similarity to steroids (for muscle development) or as a sleep aid.
3. Individuals who abuse GHB as a weapon for sexual assault.
These categories are not mutually exclusive and an abuser may use the drug illicitly to produce several effects. GHB is frequently taken with alcohol or other drugs that heightens its effects and is often found at bars, nightclubs, rave parties, and gyms. Teenagers and young adults who frequent these establishments are the primary users. Like flunitrazepam, benzodiazepine is often referred to as a "date-rape" drug, and GHB involvement in rape cases is likely to be unreported or unverifiable. GHB is quickly eliminated from the body making it harder to show up on a drug test; and its fast onset of depressant effects may render the victim with little memory of the details of the attack.
There are clear similarities among the withdrawal symptoms seen with most drugs classified as depressants. In the mildest form, the withdrawal syndrome may produce anxiety and insomnia (usually the same symptoms that initiated the drug use to begin with). With a higher level of dependence, tremors and weakness are also present, and in its most severe form, the withdrawal syndrome can cause seizures and delirium. Unlike the withdrawal syndrome seen with most other drugs of abuse, withdrawal from depressants can be life threatening requiring drug detox.