Is it possible to change the way your mind and brain work?

I have ADHD combined and was diagnosed when I was a child. My pediatrician believed that I would grow out of it and did not want to administer stimulant treatment. Throughout school, I noticed that I could not concentrate on one task at a time, it was like so many different thoughts were running through my mind. For example, I would be daydreaming in class or doodling on my calculator. People did not respond well to me because I was too forthcoming and what not.

I want to know if it is possible to change the way your mind works? Teachers have told me that they have noticed random"bursts" of intelligence in my work. Basically, I would be able to focus on courses and material that I found interesting. However, now I feel that I can't concentrate on anything for more than 5 mins. My iPhone has been such a hinderance to me as I will always go and surf the net whenever I'm in class or text people who don't particularly like me. I'm in college now and I have been able to get by decently… Granted in the courses that I actually found interesting.

I know it's impossible to actually change the way your brain functions. I understand the neurotransmitters and how the normal balance can be deviated in some individuals who have mental disorders. It's frustrating because I actually want to be able to focus on one task at a time and execute better impulse control. I'm 21 years old and I just feel like my brain is working against me. I don't know what I'm doing wrong. I exercise at least once a day and eat plenty of healthy foods. My parents tested me for Bipolar Disorder, Hypothyroidism/Hyperthyroidism, Mania, etc. Doctors say that I'm fine. People tell me that I'm very awkward because I "zone" out when they talk to me and often blurt out random statements that don't fit the conversation well. This is bad because I don't think that it's okay to be this much of a scatter brain. And every time I try to sit down and do school work my brain literally shuts me down. What should I do? Is it possible to train the mind to focus on one thing at a time.

You have no choice but to find ways to master this internal chemical pattern. You are already a good Observer/Witness of it and able to see how it interferes with your experience of living.

First, research meditation approaches and begin this practice in some form… To daily improve your Awareness of what is happening in your thought system… And start gaining mastery/control of the internal reactions caused by chemical fluctuations in your brain. You can do this through persistent practice.

We CAN become Mindful/Aware of our impulses and inappropriate behavior, when we realize we're NOT the patterns… Rather we're the OBSERVER of them.