The 6 Classifications of Drugs

When considering only their chemical makeup, there are six main classifications of drugs: alcohol, opioids, benzodiazepines, cannabinoids, barbiturates, and hallucinogens. Out of all the thousands of drugs that are out there, both prescription and illegal, each one can be categorized under one of these six headings. 

Classifications of drugs are also based on the various effects they have on the mind and on the body. For example, some drugs have a tendency to make a user active and energetic while others make an individual feel relaxed and calm. These classifications of drugs in this article are entirely based on chemical similarities and are not grouped by their overall effect, although sometimes there is some overlap between the classifications.


The Six Classifications of Drugs

Alcohol is the single most widely abused substance throughout the world, and the United States is no different. Legal to some varying degrees in all 50 states, alcohol impacts several of the body’s basic functions. This causes a wide variety of effects on those who drink it. Alcohol has the ability to create feelings of euphoria and it lowers inhibitions, but for those who begin to imbibe while they are sad or angry, it can greatly magnify those feelings as well. In addition to its effects on the mood, alcohol also severely impairs judgment, perception (both emotional and physical), and reaction times. Some forms of alcohol include:

  • Beer
  • Wine
  • Liquor
  • Sake
  • Mead
  • Hard ciders
  • Hard seltzers
  • Wine coolers


More commonly referred to as opiates, opioids are either derived from the drug opium or a series of synthetic chemicals designed to mimic opium. Opiates work by interacting with neurotransmitters in the brain and blocking the signals that they are sending. This enables opioids to be used as extremely powerful painkillers, but they also induce feelings of intense pleasure, which is one of the reasons they are so addictive. Opioid addiction is one of the most serious problems faced by America today. Opiates are one of the most addictive substances known today, and they are also some of the most lethal. Some popular examples of opioids include:

  • Morphine
  • Codeine
  • Oxycodone (OxyContin, Percocet)
  • Hydrocodone (Vicodin, Norco)
  • Fentanyl
  • Heroin
  • Methadone
  • Buprenorphine (Suboxone, Subutex)
  • Hydromorphone (Dilaudid)
  • Tramadol


Benzodiazepines, more commonly known in America as Benzos, are a classification of drugs that function by interacting with a neurotransmitter in the brain called gamma-aminobutyric acid-A (GABA-A). Each different form of Benzodiazepine interacts with GABA-A differently, which is how they are each able to affect the body and mind differently from one another. They are prescribed to treat a varied set of psychiatric conditions and sleep problems, but they are also very widely abused, and highly addictive They will very probably cause numerous medical and psychiatric problems if they are not used in the medically prescribed way. Some examples of benzodiazepines include:

  • Diazepam (Valium)
  • Alprazolam (Xanax)
  • Lorazepam (Ativan)
  • Clonazepam (Klonopin)
  • Temazepam (Restoril)
  • Chlordiazepoxide (Librium)
  • Oxazepam (Serax)
  • Midazolam (Versed)
  • Triazolam (Halcion)
  • Flurazepam (Dalmane)


Cannabinoids are a classification of drugs that have similar chemical compounds to tetrahydrocannabinol (THC), the active agent in marijuana. Cannabinoids create feelings of elation, but they do also have a chance of negatively impacting your mental and physical functioning. Cannabinoids are the second most widely abused drug in the world, and they are becoming increasingly legal in more and more states. They are considered to have little to no chance of physical addiction, especially compared to other drug classifications. Some example of cannabinoids include:

  • Cannabis (THC, Delta 8, Delta 9)
  • Hashish


The functioning of the central nervous system is slowed down when someone takes barbiturates. This classification of drugs is a derivative of the chemical barbituric acid. Barbiturates were historically popular for the treatment of psychiatric and sleep disorders and reached their peak notoriety in the 1950s and 1960s. They are still used for anesthesia and to treat a wide variety of conditions like epilepsy and even headaches. They are also extremely addictive and can present a very high overdose risk as they cause many bodily systems to shut down. Some examples of barbiturates include:

  • Phenobarbital (Luminal)
  • Secobarbital (Seconal)
  • Amobarbital (Amytal)
  • Pentobarbital (Nembutal)
  • Butalbital (found in Fioricet, Fiorinal)
  • Thiopental (Pentothal)
  • Butabarbital (Butisol)
  • Methohexital (Brevital)
  • Primidone (Mysoline, metabolizes into phenobarbital)
  • Barbital (Veronal)


Hallucinogens are drugs that alter the thinking processes and the perception of those who take them. These perceptions are altered in such a manner that leads to significant distortions and fragmentations of reality. Hallucinogens have the ability to affect one’s perceptions in a vastly different manner than many other drugs. Popularly, the influence of these drugs represents experiences of new and even expanded consciousness. For example, some individuals may experience synesthesia (mixed sensory experiences, such as seeing sounds or hearing colors). Other common occurrences produced by this classification of drug include hallucinations (seeing things that aren’t actually there), an altered sense of time (feeling like hours have passed but it has only been a few minutes or vice versa), and dissociative experiences (not being inside your physical body or not feeling connected to reality). These drugs carry a very low risk of addiction or fatal overdose but can alter the mind in a lasting way if taken in too great a quantity. Some examples of hallucinogens include: 

  • Lysergic acid diethylamide (LSD)
  • Psilocybin (found in magic mushrooms)
  • Mescaline (found in peyote cactus)
  • DMT (Dimethyltryptamine)
  • MDMA (Ecstasy)
  • Salvia divinorum
  • Ketamine
  • PCP (Phencyclidine)
  • Ayahuasca (contains DMT)
  • Ibogaine

Want To Learn More About Discovery Place?

Discovery Place in the beautiful hills of Tennessee offers long-term recovery programs for those who are suffering from drug and alcohol addiction. Most staff members have been through the program themself and know what it takes to heal from the devastating effects of drug and alcohol addiction. At Discovery Place, we provide psycho-education on the classifications of drugs among others for individuals to understand the addiction process and begin a life of recovery.

Need to talk to someone right now? We’re here 24/7. Give us a call – 800-725-0922.

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