The jaunty subtitle is: How our brains make fatty foods, orgasm, exercise, generosity, vodka, learning and gambling feel so good. I skipped the gambling chapter in this library book, and many of the other chapters looked brand new but the pages on orgasm were well-worn, with the corners dog-eared and worn off. Hmmm.

This book was more technical than I expected, and less focused. I was hoping for some transcendent prediction or behavior guideline but got nothing more than an imagined “baseball cap of happiness” by the last chapter. Humph. Many science fiction books predict far more pleasurable brain stimulation practices in the future.

Nevertheless, his excruciatingly detailed explanation of some research I had seen summarized elsewhere helped me to understand why a blunted dopamine pleasure circuit might drive compensatory overeating. This lends credence to Michael Pollan’s assertion that “the banquet is in the first bite.”

David Linden does an excellent job of explaining how addiction works. The ancient Greeks were right: Moderation in All Things. Binging on something (chocolate, alcohol, sex) turns “liking” into “wanting,” then “craving.” He describes how it lights up the brains of humans, monkeys and rats. Binging on substances (including food) or activities (sex, gambling) changes the brain by downregulating the dopamine receptors. Too much happy-juice burns out a few of the circuits.

But wait! There’s more. If addiction is defined as craving and you get it by binging, is that the same as “physical dependence?” Nope. You can crave booze without actually having the DTs.

Physical dependence is created with a zillion small hits, like nicotine and caffeine. When you are physically dependent, withdrawal can lead to depression, lethargy, irritability and the inability to derive pleasure from other activities. No wonder people tend to substitute a new addiction (like daily running) for an old one (like daily drinking).

He is crystal clear about the importance of genetics in being addiction prone and he describes the different kinds of inheritable dopamine systems. Here’s a quote:

One tantalizing observation concerns the gene for the D2 subtype of dopamine receptor, a crucial component of the pleasure circuit. A particular form of this gene, called the A1 variant, results in reduced expression of D2 dopamine receptors within the nucleus accumbens and the dorsal striatum. Carriers of the A1 variant are, as a result, significantly more likely to become addicted to alcohol, cocaine, or nicotine. Furthermore, among alcoholics, those with the A1 variant tend to be more severely affected, with earlier age of drinking onset, more severe episodes of intoxication, and more unsuccessful attempts to quit. In families with a strong history of alcoholism, brain scanning has revealed that those family members who were not alcoholics had more D2 receptors in the nucleus accumbens and the dorsal striatum than those who were. Taken together, these studies suggest that elevated levels of D2 receptor may be protective against certain forms of drug addiction.

So, if you get more pleasure out of it, you consume less? Maybe it is time to more fully appreciate that the banquet is in the first bite…