In psychiatry, it is quite difficult to foresee the reaction to the treatment. When it comes to the selection of the drug, the situation gains more and more significance. Because the reaction to the drug takes a specific period of time based on the patient. Sometimes, this may take up to 3 months. If the preference is not correct, a second drug is prescribed, and it might be necessary to wait that long once again.
Thus, the question “how could we predict the correct drug on the first try?” is highly prioritized in the scientific field. There is a quite a dense literature accumulation on this matter.
Prediction value of parameters like various biological and psychological ones, etc. has been analyzed.
One of them is named pharmaco-EEG. This is a method of prediction. A small dose of drug is administered to the patient. This is called a “test dose”. The quantitative EEG (Q-Electroencephalograph) taken before the administration of the drug, and the QEEG data recorded at specific intervals following the administration of the drug are compared. If the inception profile gets normalized slowly, it is considered that the drug given on a test dose will be effective in the future. Therefore, for the instance of depression, the reaction to treatment can be predicted in a couple of hours, without having to wait for weeks.
Pharmaco-genetic is another one. Here, the speed the patient metabolizes the drug at, in other words, the speed the drug is discharged from the body at is researched. Genes in a personal material like salivation are examined in particular. Considering the fact that the amount received by the brain would be insufficient if the patient swiftly discharges a specific drug from the body, the information is obtained concerning the need to avoid that drug. Or if it is slowly discharged from the body, it can be detected that it may reach toxic levels in the brain, and that it should not be preferred accordingly, and that the ones that are metabolized normally can be easily administered.
Many biological signs similar to these ones can be a subject of research.
As a result, the points agreed upon can be summarized as follows:
- A drug found to be useful in the history of the patient will most probably be useful again.
- A drug that is useful for the relatives the patient has blood ties with could be preferred based on genetic reasons.
Other than that, physicians may choose to apply a trial-and-error method based on personal preferences.
My experience on this topic dates back to long years ago. I cannot continue without remembering Prof. Dr. Turan İtil, who was a guiding light for me in the efforts I put in the field of pharmaco-EEG for many years in America. He was one of the pioneers of pharmaco-EEG. Moreover, the International Pharmaco-EEG Society (IPEG) gives awards to researchers every year in regard to his dignity. I would also like to state that the thesis I wrote was on this topic.
In recent years, however, we have detected the benefits of the pharmaco-genetic method and started to implement it.
The second method, pharmaco-genetic, provides information about the process that continues until the drug has reached the brain, while the first method (pharmaco-EEG) puts forward what’s going on in the brain. Thus, the entire journey the drug makes in the body is enlightened.
In brief, today, it is possible to reach predictive data that are way beyond the maximum performance even the most experienced clinician could possibly show based on trial-and-error, which is around 2/3 in depression.
The developments achieved on this matter lead us to gladly predict that even greater steps will be taken in the future.