Ketamine is an artificial compound that is used as anesthesia during clinical practice to induce loss of sensation. Sometimes, doctors prescribe it for off-label (not under the approval of the Food and Drug Administration, FDA) use as an antidepressant. It has also been found that ketamine has the tendency to induce hallucination in people, and as such is used by people outside medical prescription.
Because of its use to fight depression, plus its increasing use outside medical prescriptions, it is believed that it tends to cause addiction in users. A study has been ongoing to find out the reason for this, and recently researchers at the University of Geneva have discovered proof that rules out this belief.
How exactly did this happen?
The team studied the effect of ketamine on specific brain regions in mice and compared the results to the effect of cocaine on mice brains. They focused on two brain parts – the ventral tegmental area, VTA (involved in reward, motivation, cognition, and aversion), and nucleus accumbens, NAc (involved in psychomotor, cognitive, and emotional functions, including reward and pleasure).
They divided the mice into two groups: in one group, they administered ketamine, and in the other group – the control group – cocaine. After observations has been made on both groups, the researchers noticed that just like other drugs, administering ketamine to the VTA caused more dopamine (the neurotransmitter responsible for pleasurable feelings) to be yielded. The dopamine produced moved to the nucleus accumbens where neurons become activated.
Meanwhile, in the control group, they observed that the effect of dopamine production on the NAc, as induced by cocaine, lasted longer than it did in the mice in the first group which received ketamine. They noted that this was because ketamine caused a change in the NAc negative feedback system, plus that it led to a decrease in the activity of nerve cells in the ventral tegmental area which usually hinders the function of Gamma-aminobutyric acid – a neurotransmitter that causes a calming effect. This process shows that ketamine is not linked to causing lasting pleasurable feelings, thereby, it cannot lead to addiction by the user.
Finally, the team concluded the research work by comparing how much the mice in both groups desired ketamine and cocaine after exposing them to some addictive behaviors.
The results from the study on mice can be extended to humans, indicating that ketamine does not have an addictive effect on humans. This might prove to be of significance regarding the way the drug is regulated moving forward.
In conclusion, ketamine produces anesthetic effects on humans and can be used as an antidepressant, but it does not lead to addiction in humans. More research might be needed to confirm these findings.