Psychomotor City

As is the usual case, my special friend always manages to inspire me. We'll call him my muse for all things unconventional and interesting. Today's subject matter is no exception. I can't say that I agree with all the views in the research I found on the subject, but it definitely makes for a fascinating topic.

Dopamine.

It's at the core of our sexual drives and survival needs, and it motivates us to do just about everything. This mechanism within the reward center of the primitive brain has been around for millions of years and has not changed one bit. Rats, humans, all mammals for that matter, are very similar in this respect.
Dopamine is behind a lot of the desire we associate with eating and sexual intercourse. Similarly, all addictive drugs trigger dopamine (the "craving neurochemical") to stimulate the pleasure/reward center. So do gambling, shopping, overeating and other, seemingly unrelated, activities. Go shopping: dopamine. Smoke a cigarette: dopamine. Computer games: dopamine. Heroin: dopamine. Orgasm: dopamine. They all work somewhat differently on the brain, but all raise your dopamine levels.
You get a bigger blast of dopamine eating high-calorie, high-fat foods than eating low-calorie vegetables. You may believe that you love ice cream, but you really love your blast of dopamine. You're genetically programmed to seek out high-calorie foods over others. Similarly, dopamine drives you to have sex over most other activities. With dopamine as the driving force, biology has designed you to engage in fertilization behavior to make more babies, and urges you to move on to new partners to create greater genetic variety among your offspring.
Your primitive brain accomplishes these goals of more progeny and promiscuity by manipulating your brain chemistry, and thus your desires and thoughts. High levels of dopamine increase sexual desire, encouraging you to behave recklessly. The thrill of a new affair and the rush from using pornography are examples of high dopamine. Unfortunately, consistently high levels of dopamine lead to erratic behavior and compulsions that are not conducive to survival. Most mammals, therefore, evolved with defined estrus periods when they "go into heat." The rest of the time they are more or less neutral about sex (yeah, right!). A balanced level of dopamine is necessary for good mental health. When dopamine drops, you feel like something is dreadfully wrong. Too much dopamine also leads to reckless behavior and restless anxiety, which can be quite severe. These uncomfortable feelings are then projected onto your partner. Bingo! Suddenly, he or she doesn't look so appealing. This is a very uncomfortable cycle to experience in your intimate relationship. During the "hangover," or "low-dopamine" portion of the cycle, you may feel abandoned, or as if someone is demanding things from you in ways that you cannot tolerate. Or you may desperately seek new highs (alcohol, sweets, new partners, pornography, and so forth) to raise your dopamine levels again.
Perhaps you can see how this cycle of highs and lows, or attraction and repulsion, can make your relationship feel more like a roller-coaster ride than a romantic fairytale. It is like starting and stopping in heavy traffic. It shows up in lovers' lives as intense attraction, followed by behaviors that tend to separate them. This is pretty daunting stuff and can seriously make an otherwise sane person go completely off the deep end. This kind of behavior is similar to that of a meth user, only in that case, it's totally chemical and not natural in the least. Put the two together and you have a recipe for disaster.