Over the long history of addiction, there has been a central tension that has shaped how addiction is treated: Is addiction a choice or the consequence of biology? For most of the past 100 years, the general bias, even among health care workers, has been that addiction is the result of bad choices. Only recently has there been a push to recognize addiction as the result of biological changes in the brain. The drive to classify addiction as a disease has been met with resistance, some of it quite reasonable. What is missing in this argument, which is only now beginning to be discussed, is whether both of these ideas can work together to further our understanding of addiction. My contention is that biological theories of addiction are best understood in light of psychological theories and vice versa.
To start with the biological, substances have been shown to cause structural changes to the brain. Autopsies of chronic alcoholics exhibit smaller and lighter brains than other people of the same age and gender. MRIs and CT scans have also demonstrated that long-term drinking actually shrinks the brain. 50 to 75 percent of heavy drinkers demonstrate a level of cognitive impairment, even after detoxification and abstaining from alcohol. In fact, alcohol dementia is the second-leading cause of adult dementia. Clearly, there is evidence that biology matters.
Methamphetamine, or "speed," for example, can trigger brain cells to self-destruct. The drug damages cells that produce dopamine, a chemical in the brain that helps to create feelings of pleasure and excitement. When dopamine levels remain constant, people can feel enjoyment from ordinary daily pleasures. When there is a shortage of dopamine, people may feel depressed, fatigued or withdrawn, oftentimes leading people to fill that deficiency in self-destructive ways.
Here is where the biological and psychological become intertwined. If everyone who drank or used an illicit drug felt as badly after their first use as they felt after their 50th use, there would be many fewer people suffering from addiction. Put another way, I often have patients berating themselves in my office because they cannot understand why they can't just stop drinking or using. I generally ask the patient to imagine going back to the first time they used their drug of choice. I then ask them if they believe they would have continued to use, knowing what they know now. I have never had a patient tell me that they would have continued to use despite this knowledge. This suggests that for some reason the knowledge of the consequences of drinking or using, at some point, is not enough to stop the use. The most rational explanation for this change, in my mind, is that the changes in the brain that we have discussed make it much more difficult to make the decision to stop using.
As such, what may start off as teenage experimentation can turn into an addictive illness because of the damage that substances of abuse cause in the brain. What starts off as more of a choice can turn into less of a choice because of the development of a brain disorder. What has also become clear is that the younger a person is when they start using alcohol or illicit drugs, the more likely they are to develop a substance use disorder. This is likely because the parts of the brain that are involved in planning and mature decision making have not yet matured in adolescents.
Neuroscientific explanations of addiction support that substances of abuse change the anatomy of the brain, which can lead to addiction. A recent article in the New England Journal of Medicine stated that "the concept of addiction as a disease of the brain challenges deeply ingrained values about self-determination and personal responsibility that frame drug use as a voluntary, hedonistic act." The authors explain that "this concept of addiction appears to some to excuse personal irresponsibility and criminal acts instead of punishing harmful and often illegal behaviors."
The reality is that neither theory can stand on its own in providing a complete explanation of addictive illnesses. Even people with other chronic illnesses need to take responsibility for their actions and habits as part of their treatment. For example, it is not enough for a diabetic to get regular insulin shots. They need to monitor their sugar intake as well. Similarly, addiction is a disease that needs to be addressed with evidence-based treatment, and at the same time, requires people to implement behavioral changes.
In order to fully understand and effectively treat a person with addiction, we need to factor in both the biological and psychological theories. There is no reason to ignore the brain when we talk about the mind and vice versa. In fact, these theories offer much more potential for lasting recovery for patients if we are willing to allow them to work together.
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