Obviously, music isn't a chemical substance. However, I do think the idea remains the same. It affects the mind and body, is used to treat abnormal conditions, and recreational users utilize it for the effects it has on their central nervous system.
Definition three is what formed the connection in my mind of how I use music and how it affects me in a drug-like manner. For years, I have used music during workouts, before parties, and as a general mood enhancer. It wasn't until recently that I realized just how much it does affect me.
I spend quite a bit of time driving alone and realized that after driving for extended periods of time with the music blaring, I would often leave the car and arrive at my destination like I was coming down from a caffeine high or other stimulant. It then dawned on me that that is exactly what was happening. I was using the music to keep me stimulated and up while driving alone. It fought off boredom and loneliness and kept me moving forward. Many times I am not looking forward to arriving where I am going and it often took my mind of the impending meeting as well.
After realizing this, I have been driving in complete silence for the last week. No music or YouTube videos playing. At first I was really bored and continually caught myself reaching for the power button on the radio. However, after a couple days, I noticed that I arrived at my destination ready to work and get things going. It had become the perfect time for meditation and focusing myself.
An unexpected side effect was that my "music sensitivity" went way up. I use this phrase because it seems completely analogous to insulin sensitivity. The less you flood your system with the substance, the more sensitive your body becomes to it and the better able to manage and utilize it when you need it. Now when I put on some loud rap music at the gym, I actually notice a huge effect on my nervous system. Everything heightens and comes alive.
This even-keeledness throughout the day lets me get a lot more done and keeps me from constantly going through ups and downs along the way. It is just so similar to the feeling you get when you nail your diet and no longer notice the mid-afternoon slump after a carb-heavy lunch. Instead, the energy is just constant all day. The added benefit of getting a huge kick from music once again at the gym is just the icing on the cake.