Depression and PTSD can be debilitating diseases and are often difficult to treat.
Ketamine in low doses has been shown to be effective in breaking the depressive cycle and rendering a patient more susceptible to traditional treatments, or in some cases, relieved of their depression and or PTSD for many months to over a year. Keep in mind that as a rule, the antidepressant effects of ketamine last for one to two weeks, so it is important to have a mental health care provider to go to for further treatment as soon as possible.
How does ketamine relieve depression?
Ketamine binds to the NMDAR receptors in the brain. This is how it exerts its anesthetic effects. When it binds to the NMDAR receptors, it blocks them. There are other drugs which can also block these receptors, but unlike ketamine, these drugs turn off production of proteins. But ketamine actually causes burst activity in these neurons so production of BDNF (brain-derived neurotrophic factor) is actually increased. This then leads to creation of more neurotransmitters that lift depression. These effects are usually seen as relief of depression within just hours of treatment, very often by the time of discharge home.
Another positive effect of ketamine on depression or PTSD is that it has been shown that when a patient receives low dose ketamine, then is started on a traditional oral antidepressant, the effects of the traditional medication can manifest as quickly as one week instead of waiting a month or more to gauge effect.
Information on this effect of ketamine can easily be found in greater detail by using a search engine, so I am not going to go into too much detail here.
Will every patient who receives ketamine achieve their desired result? This cannot be guaranteed.
There are many different success rates quoted on various websites dealing with ketamine therapy for depression. I can only relate my experience with my patients over the last few years. I think the realistic success rate lies between 50 and 60 percent. By success, I mean ketamine actually relieved the patient's depression and allowed them to return to a normal life while getting further treatment, or sometimes the ketamine relieved the patient's depression and no further treatment was necessary.
There are also different methodologies for using ketamine to treat depression. All involve intravenous infusion of a low dose based on body weight, and given over a short time period, usually 45 minutes to one hour. Methodologies include single dose, a series of four doses given evenly spaced over a two week period, and a series of six doses given evenly spaced over a two week period. Which is best is difficult to answer. I can only relate that in my experience I have seen suicidal patients brought back from the brink of the abyss with a single treatment, and I have seen patients with severe debilitating depression who got relief with the six dose induction method but after the initial one or two treatments did not display any noticeable improvement, but only after all six treatments. I even had one patient who received only a single infusion and had relief of depression last 19 months before return for another infusion. Again, this is more an exception than the rule.
It is up to the individual patient to discuss the treatment with their mental health care provider and other support groups to decide on the number and frequency of treatment.