Humans struggle with addiction. We can be challenged by behavioral or substance addictions, or both, which manifest in the brain in nearly identical ways. Why is addiction so common and how can we work to overcome our susceptibility to excess?
Certain behaviors such as sex, gambling, shopping, eating, and OCD as well as the consumption of substances such as sugar, alcohol, tobacco, marijuana, cocaine, methamphetamine, and opioid drugs act on an ancient area of the brain called the mesolimbic dopamine system. The mesolimbic dopamine system, sometimes called the lizard brain, is responsible for regulating rewards associated with activities that ensure survival: food, procreation, and social interactions. Inappropriate signaling within this part of the brain can easily hijack our behavior and cause us to act in illogical ways — our brains think survival is at stake.
The main neurotransmitter responsible for regulating activity in this part of the brain is dopamine. We’re familiar with the rewarding results of a dopamine influx — we can thank it for the calming pleasure of tasting a heavenly dessert or for feeling weightless and euphoric after orgasmic sex. When our brains are flooded with dopamine after experiencing those activities, it remembers them and conditions us to want to repeat the pleasurable experience. Dopamine also regulates compulsion and perseveration, which drive us to obsess over, ruminate on, seek out, and repeat these enjoyable dopamine-producing activities.
In this excellent video, Dr. Ruth Potee explains that an easy way to think about the effects of dopamine is to consider 100 as an average baseline dopamine level for most healthy individuals. Some of us have naturally sunny dispositions and might have a slightly higher dopamine baseline, maybe a level of 110, while others might have a slightly lower one at 90. Regardless of our natural baseline, the effect of addictive substances and activities on our dopamine levels is the same. Imagine you’ve been excitedly anticipating peach season all year. When you bite into the summer’s first perfectly ripe and syrupy peach and the juice drips off your chin as you slurp up the sweet nectar, attempting to not make a complete mess, your dopamine level might spike to 130. A relaxing glass of wine might bump our dopamine to 140. Incredible sex could jolt our dopamine levels to 160. Similar spikes can happen with activities such as shopping or gambling when we view the outcome as rewarding. After these activities, our system recognizes the corresponding dopamine spike as within normal limits and our dopamine levels return to normal. The response to many addictive drugs is far greater. Dr. Potee explains that the dopamine spikes seen from drugs such as cocaine and methamphetamine can be as high as 350 and 1250 respectively (from the baseline of 100). When we introduce any of these activities more than is evolutionarily normal (i.e. consume foods with added sugar all-day, every-day, over-indulge in alcohol, or engage in compulsive sex) or when we consume highly addictive drugs, our brain begins to mute dopamine’s effect.
When dopamine floods the brain constantly as with chronic over consumption of substances like sugar or alcohol, when we frequently engage in activities like shopping, gambling or gaming, or when it surges dramatically during drug use, our brain responds by down regulating the neurotransmitter. Dopamine’s effects can be blunted in three ways:
- By reducing dopamine production,
- reducing dopamine receptors, or
- increasing clearance of dopamine in the neural synapses.
The stronger the dopamine release from an activity and the more frequently that activity occurs, the more dopamine will be down-regulated. What happens when dopamine gets down-regulated? We end up with a baseline dopamine level that’s lower than our normal baseline. If we were at a dopamine level of 100 pre-overconsumption, then we might end up at a baseline of 70 with chronic overconsumption of alcohol, or far worse, at a 40 if we’ve become addicted to a synthetic drug like meth or opioid drugs. Recall the feelings dopamine helps regulate: reward, euphoria, pleasure, compulsion, and perseveration. When our dopamine baseline drops below the normal range, everything becomes less pleasurable, we start to feel less engaged with the world around us, and the only thing we’re truly interested in is the next hit of dopamine from the substance of choice. As dopamine levels continue to drop, the feelings of malaise increase as does the draw toward actions that will elevate neurotransmitter levels. In addition to the effects on the mesolimbic dopamine system, addiction also affects brain functions such as motivation, impulse control, attention, problem solving, planning, learning, and memory. Yikes.
Addiction is not a failure of will or a character flaw, it’s the result of a behavior-mediated chemical imbalance, with some people being more susceptible to developing that chemical imbalance than others. There are three key factors that can dramatically increase the chance of struggling with addiction: genetics, age of first use, and traumatic life events. Many experts agree that about 50% of the predisposition to addiction comes from genetics — of course if we look hard enough, most of us can find someone in our family tree who battled addiction — meaning most of us should take the genetic risk of addiction seriously. The age of first use is another extremely powerful indicator for potential problems — the earlier someone begins using a substance, the greater an impact that substance has on their developing brain. A recent study claims that 90 percent of Americans who are addicted to tobacco, alcohol, or other substances began use before age 18. Keep in mind age of first use transfers from substance to substance, meaning if you started smoking cigarettes or consuming large amounts of sugar as a teen, you’ll be more susceptible to all types of addiction. Finally, trauma, particularly childhood trauma, is highly correlated to substance abuse and addiction later in life. But of course, that doesn’t mean that if you don’t have a genetic predisposition, didn’t use substances early, and are trauma-free you can’t become addicted.
Many physicians now view addiction as a brain disease — sometimes it develops quickly as in the case where someone has multiple predispositions, but sometimes it develops slowly. Regardless of how addiction develops, it can be fixed, but not without significant effort.
As I detailed in a recent post titled Rethinking Moderation, many of us are unknowingly consuming far greater amounts of socially acceptable addictive substances, like sugar and alcohol, than we realize. This chronic over-consumption pattern is insidious — it sets us up for frequently feeling discontent and for a slow, gradual slide into dependance and eventually addiction. In this pre-addiction stage, we might wonder why we feel more “meh” than we used to. We might be frustrated at our struggle to resist that gooey fresh-baked cookie we see in a bakery’s window or pouring a glass of wine immediately upon walking in the door after work. The uncomfortable reality is that regardless of social acceptability, copious consumption of addictive substances changes the way the brain functions —we’re more easily agitated, have lower motivation, experience brain-fog, and struggle with learning and memory. When we flirt with over-consumption addiction isn’t inevitable, but it’s a distinct possible outcome.
The good news is that it’s entirely possible to avoid or break addiction. Weaning ourselves off of the behaviors and substances that artificially increase dopamine levels might suck for a few days, weeks, or months. But slowly, with time and effort, the hold that those things had over us — over our feelings, actions, and attitudes — will begin to lift.
The struggles once masked and the feelings once sought with consumption can be handled in much healthier ways.