At first, I did promotional work for gastrointestinal drugs and antibiotics. I would do tests to identify bacteria and find out what spectrum antibiotic would have what kinds of effects . . . things like that; being able to predict the results, and following the whole process through until the final results were obtained, with precision. I have always liked doing things systematically.
One day, I was told that I would be specializing in the central nervous system from that point on. At first, I thought that working on central nervous system drugs would not suit me, I suppose because I thought that mental illnesses are not so easy to quantify mathematically: in this field, treatment results vary widely depending on the patient's condition and lifestyle, and it's often the case that a drug you think should work based on the data doesn't work. It might work really well in one patient, but not at all in another patient.