By: Ralph Ryback M.D, (Psychology Today)
Original Source: www.psychologytoday.com
The answer lies in the brain
Is it possible for someone to become instantly addicted to a drug? Most people might say no. First individuals must try a drug and realize that they like it. Then they might start to use the drug more frequently. Eventually, once they have used the drug enough, their brain begins to lose the ability to function without it. They spend all night dreaming about their next fix. They miss work. They miss birthdays. They miss appointments. There are no consequences that seem to outweigh getting high. This is addiction.
But what if individuals skip a few steps? What if they try the drug once and know immediately they are hooked, and that the urge to use again and again will likely never leave?
Instant or “born” addicts are people who claim they were hooked on a drug after using it for the first time. For these “instant addicts,” the first exposure to a drug is defined as a transformative experience. David Carr, a recently deceased writer for The New York Times (and a recovering drug addict), described the first time he tried cocaine as a “Helen Keller hand-under-the-water moment.” People who suffer from an instant addiction often describe the drug as filling a hole inside their mind that they didn’t even know was there in the first place.
As it turns out, the “hole-inside-their-mind” metaphor is surprisingly accurate.
Too few dopamine receptors
Research has shown that people who develop drug addictions are often missing something key inside their brain. Compared with the general population, drug addicts have far fewer D2 receptors, which are a class of dopamine receptors responsible for receiving messages in the brain associated with reward, pleasure and motivation. Without a sufficient number of these receptors, a person cannot experience the proper amount of enjoyment in everyday activities. When a person uses drugs, this causes the brain to release a tremendous amount of dopamine, far greater than any amount that occurs naturally. This influx of dopamine might compensate for the lack of receptors, making the drug user finally feel “normal or better.”
Neurobiologically and physiologically speaking, the brain’s pleasure and reward circuitry has been hijacked (link is external).
Considerable research has fueled the theory that people who become addicted to drugs or alcohol do so because of this chemical imbalance. Scientists found that non-drug users with low levels of D2 receptors were more likely to describe the experience of taking Ritalin, a drug that fuels the dopamine system, as pleasant (link is external). Conversely, they observed that non-drug users with high levels of D2 receptors found that taking Ritalin was uncomfortable or even frightening. When researchers (link is external) artificially added D2 receptors to rats, they found that the rats self-administered considerably less alcohol than they consumed previously. It seems as though having too few D2 receptors opens the brain to drug abuse, whereas having too many D2 receptors serves as a sort of protection mechanism.
Genetic and environmental factors
How do people end up with reduced – or increased – numbers of D2 receptors? Scientists theorize that both genetics and environmental factors are to blame. The genetic component is not surprising – after all, it is well known that addiction rates, just like diabetes and cancer, increase with genetic vulnerability. How then could the environment possibly impact protein production?
Although people talk about the brain being “hardwired,” neuronal connections and protein levels are highly malleable. Even genetic mechanisms (link is external) can change – for instance, a person’s experiences and environment can determine which genes will be expressed or which genes will go silent. These genes can actively up-regulate (increase) or down-regulate (decrease) the number of receptors, depending on a person’s experiences or environment. In fact, people who use drugs start to lose D2 receptors after sustained drug use. This down-regulation of D2 receptors might be why some people gradually develop addiction — the more individuals use drugs, the fewer D2 receptors they have and the more they “need” drugs to feel normal. Others, who naturally have fewer D2 receptors, seem to be more prone to addiction — in other words, they are “instant addicts.”
Scientists still need to determine precisely how genetic and environmental factors impact D2 receptor populations. A greater understanding of biological addiction signifiers will allow clinicians to perform screening and early intervention measures.
So, can people become instant addicts? The answer is yes – sometimes. Drug addiction is a brain disease to which some people are more susceptible and others less so. Scientific research continues to expand our understanding of the brain, but future neuroscience research will unlock the keys to treating – and perhaps even curing – the addicted brain.