Chronic stress changes the architecture of the brain, due to high cortisol levels. As a result, more neurons grow in the amygdala—the region of the brain responsible for fear and anxiety. And fewer neurons grow in the prefrontal cortex and hippocampus—the regions responsible for executive functions and memory. These changes in the brain can cause many problems for an individual. The synapses within the brain, which allow neurons to communicate with each other, have an excess amount of glutamate, an excitatory neurotransmitter. This means that the neurons become more excitable than usual, and send signals to other neurons more often than usual. This excessive ‘firing’, or signal sending, leads to damage in the neurons. Unfortunately, current anti-depressant drugs do not address this issue, and mainly focus on neurotransmitters such as serotonin or norepinephrine. Ketamine on the other hand, protects neurons from the damage which results from over excitability.
Ketamine has been used as a dissociative anesthetic for several decades. Ketamine is used for burn victims, radiation patients, and in children who may be allergic to other anesthetics. Unfortunately, ketamine has also emerged in the illegal drug trade, being abused. Illicit forms of ketamine are known as Special K, Vitamin K, Super K, or the date rape drug.
Although ketamine has potential for abuse, it also has great therapeutic potential for the treatment of depression and other mood disorders. Dr. Pierre Blier of the University of Ottawa has found that ketamine is effective in treating depression and suicidal ideation. Ketamine works faster than any other drug available for depression, with effects being seen in some cases in only a few hours after the first treatment. In this sense, it is similar to other psychedelic drugs.
However, even in patients who do not have significant improvements in their symptoms of depression as a result of ketamine treatment, there may be significant reductions in their suicidal ideation. The rapid reduction of suicidal ideation is an important feature which sets ketamine apart from other anti-depressants. Suicide takes the lives of many with mental illness, and current anti-depressants may take several weeks to reduce suicidal ideation—if they do at all. Thus, the rapid reduction of suicidal ideation from ketamine may save a great many lives.
What is bringing a lot of attention to ketamine is not the fact that it helps symptoms of depression and PTSD—but the fact that it may be able to totally prevent them in the first place. Scientists use stressful situations to induce an animal model of depression. However, Dr. Rebecca Brachman of Columbia University found that when ketamine is given to mice in small doses it protects them from developing PTSD and depression in these stressful situations, even weeks after it is given to them.
We’re still not sure how this happens, or if it will happen in people. However, soldiers given ketamine as an anesthetic while being treated for burns develop PTSD about half as often as soldiers who have not been given ketamine. Therefore, ketamine appears to have a promising future as a ‘paravaccine’ for PTSD and depression, possibly providing protection for soldiers, aid workers, and first responders.
Unfortunately, there is not much incentive for pharmaceutical companies to invest in the expensive clinical trials required to have ketamine FDA-approved as an anti-depressant. The original patent for ketamine has long since expired, and there is no longer monetary motivation to run costly clinical trials. Further, although ketamine has been used in the medical setting for decades, there is still some resistance to using it as a vaccine against PTSD and depression, due to its reputation as a street drug.
Despite these barriers, ketamine is currently being used as a treatment for symptoms of depression and other mood disorders, and we can hope that researchers such as Brachman and her colleagues continue to search for preventative measures to take against these damaging disorders.