It is classified by the United States Drug Enforcement Administration as a Schedule III controlled substance, meaning that it does have a moderate potential for abuse and for the development of physical and psychological dependence, but it does have some medicinal purposes.
Ketamine’s Mechanism of Action
Ketamine is primarily described as a dissociative anesthetic drug. This means that it produces sedative effects but also produces cognitive effects that include memory loss (amnesia) and feeling as if one is detached from oneself or reality. Ketamine’s main action occurs on the neurotransmitter glutamate, in particular the N-methyl-d-aspirate (NMDA) receptor for glutamate. Glutamate is the primary excitatory neurotransmitter in the central nervous system, and the NMDA receptors are extremely important in the ability of neurons to changes the result of experience (known as neuronal plasticity). This makes them crucial in aspects of learning and memory.
Ketamine functions to block the actions of NMDA. This results in a number of effects that include sedation, anesthesia, and cognitive effects. In addition, ketamine also appears to block the effects of the neurotransmitter acetylcholine, increase the effects of the neurotransmitter gamma-aminobutyric acid (the most prominent inhibitory neurotransmitter in the brain), and may also slightly increase the function of the neurotransmitter dopamine as well as have slight narcotic effects. By blocking the actions of excitatory neurotransmitters and facilitating the action of inhibitory neurotransmitters, ketamine results in the experience of sedation, anesthesia, and mild euphoria.
Ketamine has a number of uses, both medicinal and nonmedicinal, per the book Ketamine: Use and Abuse.
Medicinal Uses of Ketamine
Ketamine’s was developed out of a need to find an anesthetic to replace the highly abused drug PCP. When ketamine was first developed, it was observed to have powerful anesthetic effects that were not associated with significant slowing of the heart or breathing rate. This finding was considered to be positive and much hope was held for its use as an anesthetic drug; however, individuals who had been given ketamine for anesthesia also reported having out-of-body experiences, near-death experiences, hallucinations, delusions, confusion, and even delirium (severe confusion combined with psychotic-like experiences). These findings resulted in ketamine being discontinued as a major anesthetic for use in humans. Ketamine still has some medicinal uses, described below.
- Anesthesia: Ketamine still is used as an anesthetic in special cases. It is used as a veterinary anesthetic, may be used in pediatric cases for anesthesia (because it does not result in decreased heart rate or respiration), and may be used in the field, as an anesthetic for wounded soldiers.
- Pain management: Ketamine is also used in pain management in veterinary medicine and in some human cases. In humans, ketamine can be used at low doses for particularly hard-to-treat issues, such as neuropathic pain (pain that is associated with injury to the tissues).
- Seizure control: Ketamine has also been used effectively in the control seizures in some individuals.
- Under research: Ketamine is currently being research as a treatment for major depressive disorder, particularly in individuals who do not respond to other forms of treatment for depression. It is also being researched as a potential treatment for certain types of substance use disorders, such as addiction to alcohol or heroin. Because of its dissociative effects, it is used in research studies to understand how the development of psychotic behavior is experienced in the brain. In these cases, ketamine is given to subjects to induce states of psychosis and the subjects are studied according to a number of different protocols.
Ketamine as a drug of abuse began to gain popularity in the 1990s as a “rave” or club drug, especially as an ingredient added to ecstasy. Ketamine is most often obtained in powder form and most often abused by snorting or inhaling it. In some cases, it may be injected. It is rarely used orally. When snorted, the effects of the drug will typically appear relatively rapidly, often 5-15 minutes after taking it. Its hallucinogenic effects are typically relatively short-lived (about an hour); however, cognitive effects, including confusion and memory loss, appear to last longer and may persist for 24 hours or more.
Ketamine is abused for its psychoactive effects. These effects typically include feelings of euphoria, sedation, and changes in cognition, as well as hallucinations and dissociative experiences. Individuals who abuse ketamine may believe that it makes them more sociable and more empathetic to other people’s feelings.
When taken at low doses, ketamine produces feelings of distortion of time, space, and mild hallucinations. People feel that they are becoming part their surroundings (melting into their surroundings), become very happy, feel sociable, and often experience visual hallucinations. At larger doses, ketamine produces a severe dissociation where the person’s perceptions appear totally detached from reality (sometimes referred to as the “K-hole”). These drastically altered states of consciousness are often appealing to certain types of individuals.
Overall, the effects of ketamine in abusers can be summarized as consisting of:
A type of hypnotic state depending on the dosage taken (At low doses, individuals experience sedation and hallucinations, and at higher doses, more dissociative effects occur.)
- A reduction in pain
- Disorientation, confusion, and a loss of touch with reality
- A loss of coordination, rigid muscles, unconsciousness, and/or a comatose like state (K-hole)
- Extreme sweating, insomnia, and extreme feeling of being vulnerable; in some cases, aggression
People initially start using drugs like ketamine for their psychoactive effects. Abuse of drugs is related to a combination of psychological and biological factors. The important question for any individual who abuses drugs is to try and understand their personal situation and why that contributed to their drug use or abuse.
A number of different behavioral signs and symptoms may be associated with abuse of ketamine. Because many of these symptoms are also associated with other forms of substance abuse, it is important to look for groups of symptoms that hang together. For example, an individual just being extremely mellow should not arouse suspicion that they are abusing some drug unless this behavior is drastically different than their normal behavior. Some signs that may be associated with abuse of ketamine include:
- Dilated pupils
- Being unusually relaxed or mellow
- Being very sluggish
- Difficulty concentrating on one train of thought
- Seeing or hearing things that are not there
- Reporting that things seem as if they are not real
- Feeling as if one is floating out of their body
- Alternating periods of insomnia and lethargy
- Extreme periods of confusion
- Periods of extreme memory loss
It remains unclear if chronic abuse of ketamine can lead to the development of physical dependence in an individual (displaying both tolerance and withdrawal). Individuals who chronically abuse ketamine will develop tolerance to the drug, but there is no defined formal withdrawal syndrome identified. Most likely, individuals who stop using ketamine after long periods of chronic abuse will experience some psychological symptoms that could include:
- Increased depression
- Increased anxiety
- Increased restlessness
- Strong cravings
Individuals who abuse ketamine and develop a substance use disorder will experience a lack of control regarding their use of the drug that manifests itself in a number of different ways. The American Psychiatric Association lists formal diagnostic criteria for all substance use disorders. In general, individuals who develop substance use disorders often use more of the drug then they originally intended to, use it for longer periods of time than they originally intended, use it in spite of experiencing a number of the negative ramifications associated with such use, fail to maintain important obligations as a result of their drug use, and develop a number of other negative ramifications associated with their drug use. These negative ramifications and inability to stop drug use indicate that the individual has lost control over their use of the drug, even though they may not realize that they have done so. Individuals with formal substance use treatment disorders require targeted and intense treatment.
Treatment for Ketamine Abuse
Treatment for an individual who develops a substance use disorder as a result of ketamine abuse would involve medical management of the individual’s cravings and psychological issues as a result of discontinuation and participation in a formal substance use disorder treatment program that should minimally consist of therapy for substance use disorders. Individuals recovering from ketamine abuse will also benefit from participation in social support groups, including 12-Step groups where they can bond with other recovering individuals, share experiences, learn from others, and develop a new and supportive peer group.
- Any individual with any type of substance use disorder should also be fully assessed by a licensed mental health clinician for the presence of any other mental health disorders, such as depression, an anxiety disorder, a personality disorder, a trauma and stress related disorder, etc. Any co-occurring disorders identified in the assessment process should be treated concurrently with the individual’s recovery from ketamine abuse.
- Many individuals recovering from ketamine abuse will benefit from outpatient therapy; however, some individuals may find that they initially need to become involved in an inpatient treatment program in order to focus on the early aspects of recovery. The decision to engage in an inpatient treatment program is made on the basis of the initial assessment, and the opinions of the treatment providers and the person with the substance use disorder.
Ketamine is a dissociative anesthetic drug that produces feelings of euphoria, sedation, and alterations of perception that include hallucinations and dissociative experiences. The drug was primarily popular in the late 1990s and early 2000s as a type of club drug, but it is still abused by younger individuals today. Individuals who abuse the drug take it for its psychoactive effects. Any individual who abuses the drug for a significant period of time runs the risk of developing a formal substance use disorder and should become engaged in a formal treatment program of recovery.