Ketamine is a rapid-acting, non-barbiturate, and non-narcotic agent that has been called a “dissociative” anesthetic because it creates a sense of disconnection between mind and body. This is quite unlike the properties of conventional anesthetics, which basically extinguish consciousness. Ketamine was first synthesized in 1962 and was later patented by Parke-Davis in 1966 as a human anesthetic. During the Vietnam War, ketamine was the most widely used battlefield anesthetic. In 1970 the U.S. Food and Drug Administration (FDA) approved ketamine anesthesia for use with children, adults, and the elderly. Since then ketamine has been adopted by many hospitals and medical offices because of its rapid onset, proven safety, and short duration of action.

The medication ketamine has many effects in the brain. It produces extremely effective anesthesia and, for more than 40 years, ketamine has been regularly used in clinics and hospitals as an effective and dependable anesthetic. Also, due to its exceptional analgesic properties, ketamine is widely used at sub-anesthetic doses for management of breakthrough pain in patients with acute and chronic pain, for treatment of neuropathic pain disorder, ischemic limb pain disorder, refractory cancer pain, as an adjunct to standard opioid therapy, and as a pediatric sedation tool for use with acutely injured children. In addition, ketamine has strong antidepressant effects and produces a dramatic improvement in patients’ mood in a matter of hours among treatment-resistant patients diagnosed with major depressive disorder.

What’s more, ketamine is a potent psychedelic agent and reliably causes powerful alterations in consciousness (e.g., in mood, perception, and thought) that naturally occur only during dreaming, memory flashbacks, psychoses, and mystical experiences. In sub-anesthetic doses ketamine consistently induces feelings of ego dissolution and loss of identity, emotionally intense visions, visits to mythological realms of consciousness, vivid dreams and memories of possible past incarnations, experience of the psychological death and rebirth of the ego, and feelings of cosmic unity with humanity, nature, the universe, and God. Unlike all other psychedelic substances (e.g. LSD, psilocybin, mescaline, etc), ketamine is a legal medication and licensed physicians can lawfully prescribe it off-label within the United States for psycho-therapeutic purposes.

Ketamine’s underlying biochemical mechanism of action on the brain is the blockade of the thalamo-cortical projections and the activation of the interactions between frontal cortex and limbic structures, which results in a specific hyperfrontal metabolic pattern in the human brain, associated with psychedelic experience (intense visions and ego-dissolution). The thalamus’ primary function is to relay sensory and motor signals to the cerebral cortex; the frontal cortex is responsible for cognitive processing of information (conscious mind); and the limbic system is the brain’s center of emotions (unconscious mind). Thus, ketamine blocks transmission of incoming signals from all sensory modalities, including signals from the outer world and one’s own body, and reinforce the interactions between cognitive mind and emotional mind. In other words, ketamine disconnects the self from the objective reality, ties cognizant and unaware levels of mind in a close loop, and removes a filter between conscious mind and unconscious mind.

Ketamine has minimum life-threatening side effects. Several unintentional overdoses of up to 10 times the amount usually administered have been documented by complete recovery. All previous clinical studies have both established its greater safety and failed to detect any long-term impairment as a consequence of its use. In fact, there is a plethora of recent studies investigating the possibility of damage related to ketamine with normal, pathological (e.g., patients with schizophrenia), and ketamine-abusing volunteers. The majority of these studies suggest that ketamine can be safely used for treatment of various psychological/psychiatric problems. In addition, more than 7,000 published reports describe ketamine’s high level of effectiveness in a variety of other clinical applications. According to several reports, ketamine in fact prevents brain damage from head trauma, strokes, heart attacks, epileptic seizures, low oxygen levels, and low blood-sugar levels.

It is important to put emphasis on addictive properties of ketamine. While widely used legally, ketamine is also used illegally as a recreational drug. Unlike other psychedelic drugs, ketamine has substantial addictive risk and there has lately been an increase of ketamine abuse. This risk is in part due to its rare pharmacological properties among psychedelic drugs. Ketamine (like DMT and PCP) does not form the acute tolerance characteristic of other drugs with hallucinogenic effects, which makes daily “tripping” impossible. Ketamine, by contrast, does not lose its potency on repeated administration over a short period of time. When ketamine is used in uncontrolled settings recreationally, it can lead to significant medical problems, including excessive sedation and respiratory depression, especially if combined with depressants like alcohol, benzodiazepines, or gamma hydroxybutyrate. Frivolous use of ketamine may also cause impairment of episodic memory and attentional functioning. Therefore, we emphasize that ketamine should never be used in any way other than for clinical applications under the supervision of qualified and licensed professionals.