“From another corner of neuroscience, we’re learning about a neurotransmitter called dopamine. Though there are more than fifty neurotransmitters (that we know of), scientists studying substance problems have given dopamine much of their attention. The brain’s reward system and pleasure centers—the areas most impacted by substance use and compulsive behaviors—have a high concentration of dopamine. Some brains have more of it than others, and some people have a capacity to enjoy a range of experiences more than others, owing to a combination of genetics and environment. The thing about dopamine is that it makes us feel really good. We tend to want more of it. It is naturally generated through ordinary, pleasurable activities like eating and sex, and it is the brain’s way of rewarding us—or nature’s way of rewarding the brain—for activities necessary to our survival, individually or as a species. It is the “mechanism by which ‘instinct’ is manifest.” Our brains arrange for dopamine levels to rise in anticipation and spike during a pleasurable activity to make sure we do it again. It helps focus our attention on all the cues that contributed to our exposure to whatever felt good (these eventually become triggers to use, as we explain later). Drugs and alcohol (and certain behaviors) turn on a gushing fire hose of dopamine in the brain, and we feel good, even euphoric. Dopamine produced by these artificial means, however, throws our pleasure and reward systems out of whack immediately. Flooding the brain repeatedly with dopamine has long-term effects and creates what’s known as tolerance—when we lose our ability to produce or absorb our own dopamine and need more and more of it artificially just to feel okay. Specifically, the brain compensates for the flood of dopamine by decreasing its own production of it or by desensitizing itself to the neurotransmitter by reducing the number of dopamine receptors, or both. The brain is just trying to keep a balance. The problem with the brain’s reduction in natural dopamine production is that when you take the substance or behavior out of the picture, there’s not enough dopamine in the brain to make you feel good. Without enough dopamine, there is no interest or pleasure. Then not only does the brain lose the pleasure associated with using, it might not be able to enjoy a sunset or a back rub, either. A lowered level of dopamine, combined with people’s longing for the rush of dopamine they got from using substances, contributes to “craving” states. Cravings are a physiological process associated with the brain’s struggle to regain its normal dopamine balance, and they can influence a decision to keep using a substance even when a person is experiencing negative consequences that matter to him and a strong desire to change. Depending on the length of time and quantities a person has been using, these craving states can be quite uncomfortable and compelling. The dopamine system can and does recover, starting as soon as we stop flooding it. But it takes time, and in the time between shutting off the artificial supply of dopamine and the brain’s rebuilding its natural resources, people tend to feel worse (before they feel better). On a deep, instinctual level, their brains are telling them that by stopping using, something is missing; something is wrong. This is a huge factor in relapse, despite good intentions and effort to change. Knowing this can help you and your loved one make it across this gap in brain reward systems.”