January 01, 2018

What Happens in the Brain When a Person Becomes Addicted?

By Jodi Gilman

The science is clear; addiction changes the brain. Animal and human studies show that neural structure, function, connectivity, neurotransmitter levels, and even epigenetics can be affected by drugs of abuse. In the past 20 years, there has been a fundamental shift in our understanding of the science of addiction and in the way addiction is conceptualized in the medical and political communities. Though, traditionally, substance use treatment has been separate from routine health care, doctors are beginning to regularly ask patients about drug and alcohol use. Medications are being prescribed by physicians that can help people with cravings and withdrawal symptoms, though there are still many barriers to this type of treatment. And politicians, largely because of the attention that the opiate epidemic has received in the popular press, are beginning to talk about public health solutions, rather than criminal justice alone, to counter addiction.

It is critically important for judges, prosecutors, and other law enforcement personnel to understand the neurobiology underlying addiction, as we shift toward more treatment-oriented approaches. Addiction, which was once thought to be merely a moral failing, is now understood as a complex disorder with discernable and measureable neural, genetic, and behavioral risk factors. Scientists now understand that the effects of drugs, particularly the dysregulation of neurotransmitters in the brain, can render an individual highly susceptible to relapse. Perhaps most relevant to law enforcement personnel, studies have shown that although individuals with addictions often need multiple episodes of treatment and recovery support, treatment does work.

What Is the Scope of Addiction?

The depth and breadth of addiction cannot be understated. In 2015, more than 20 million people (around 8 percent of the population) met diagnostic criteria for a substance use disorder. The public and policymakers are largely aware of the opioid epidemic, which has been ravishing communities throughout the United States, but addiction to other substances poses a far larger public health issue. While opioids kill more than 28,000 people per year, more than 88,000 deaths a year are related to alcohol, and more than 430,000 deaths per year are related to tobacco use. Furthermore, long before the opioid crisis emerged on the national scene, addiction has been a problem in the United States. Throughout history, there have been various approaches to counter addiction, from Prohibition-era attempts to ban alcohol, to tough-on-crime drug policies that continue to incarcerate tens of thousands of people. More evidence-based, treatment-oriented approaches to addiction have shown considerable success, though many barriers prevent those who need help from successfully entering treatment.

Addiction affects all parts of society: the individual, the family, and the community at large. The costs of addiction are staggering. Drug use causes physical health problems (e.g., cardiovascular and cardiopulmonary diseases, liver and pancreatic diseases, hypertension, stroke, cancers, etc.), mental health problems (e.g., depression, anxiety, increased suicide risk), and myriad societal problems (e.g., increased spread of infectious disease; loss of productivity; reduced quality of life; increased crime and violence, including intimate partner violence, sexual assault, and rape; increased motor vehicle crashes; abuse and neglect of children). In 2014, nearly one-third of all traffic-related fatalities in the United States were caused by drivers under the influence of alcohol or drugs. In addition to the tens of thousands of lives lost each year from addiction, substance use disorders are estimated to cost the United States more than $400 billion in lost workplace productivity, health care expenses, and law enforcement costs. Studies have shown conclusively that all treatment options—inpatient, outpatient, or residential—are more cost-effective than no treatment. In fact, according to the Substance Abuse and Mental Health Service Administration, every $1 spent on treatment saves criminal justice $7, and when added to health care savings, the savings-to-cost ratio is 12:1.

Why Do Some People Become Addicted While Others Do Not?

For better or worse, millions of people try alcohol, cigarettes, and/or marijuana, and tens of thousands try other illicit drugs. Among those who try these substances, most will not become addicted. A relatively small proportion of individuals who initiate drug use will become addicted—about 15 percent for alcohol, 9 percent for marijuana, 30 percent for tobacco, and, according to the latest data, around 20 percent for prescription opioids and 30 percent for heroin. While, on a population level, these numbers are staggering, it is important to recognize that well more than half of people who use these drugs will not develop an addiction.

Why some people become addicted and others do not is an active area of research, yet studies indicate that those at high risk can be identified at a very young age—as young as four. In a fascinating psychology study, known as the “Marshmallow Experiment,” hundreds of four-years-olds were tested on their ability to delay gratification. The children were brought into a room and given a choice: They could either eat one marshmallow right away or, if they were willing to wait while the experimenter stepped out of the room for 15 minutes, they could have two marshmallows when he returned. Most children resisted for an average of about three minutes. Some kids ate the marshmallow right away, while others were able to wait the full 15 minutes for the experimenter to come back into the room. The scientists tracked these children for more than 40 years and found that those who were least able to delay gratification had lower educational attainment, lower standardized test scores, and poorer interpersonal relationships and were much more likely to have problems with drugs and alcohol.

The Marshmallow Experiment is an example of how biology and environment can shape behaviors that have long-lasting consequences. The ability to wait for a reward is an aspect of an individual’s personality that can be shaped by positive or negative environments (parents, peer groups), can change over time from childhood and adolescence to adulthood, and can be affected by stress and adversity. Scientists understand that there are some clear predictors of who will become addicted, including a person’s genetics (i.e., children of alcoholics have a ninefold increased risk of developing an alcohol use disorder), the age at which substance use begins (i.e., the younger an individual is at initiation of drug use, the more likely the individual is to develop an addictive disorder), and environmental factors (e.g., availability of drugs, poverty, lack of family support, negative peer dynamics, cultural norms that encourage drug use, exposure to stress or trauma). Early life stress, such as physical, emotional, and sexual abuse; neglect; parental substance use; and poverty are all strong risk factors for addiction. Protective factors include involvement in school, engagement in social activities, good coping skills, and support and regular monitoring by parents. However, it is important to note that even individuals from stable, middle- or upper-class families also can go on to develop addictions. For some, any exposure to drugs, such as opiates, precipitates a dangerous cycle of craving, use, intoxication, withdrawal, and subsequent craving followed by drug use to counteract withdrawal symptoms.

What Happens to the Brain When Someone Becomes Addicted?

Repeated use of substances changes the brain, and these changes, called neuroadaptations, create a reinforcing loop that makes it harder and harder for an individual to stop using those substances. Drugs exert effects on the brain that drive the transition from controlled substance use (of which many individuals may be capable) to uncontrolled, chronic misuse. We now understand that not only do drugs exert powerful effects on the brain during addiction, but these brain changes can endure for years after a person has stopped using drugs, rendering the individual highly susceptible to relapse for years after sobriety.

Changes in the brain occur largely in three distinct “stages,” each of which involves specific neurotransmitters and brain regions. The first stage of the addiction cycle is called the “binge-intoxication” stage. In this stage, people seek out drugs for their positive reinforcing properties. Quite simply, people use drugs because they enjoy the high, euphoria, relaxation, and other “good” feelings that result from drug use. This first stage involves the neurotransmitter dopamine, which is the same neurotransmitter that is released from sex, food, and other “natural” rewards. Dopamine stimulates the reward centers of the brain, which is evolutionarily advantageous; dopamine makes us feel good when we eat food or have sex, which ensures the survival of our species. However, drugs such as cocaine or heroin overstimulate the reward centers of the brain. These drugs cause hundreds of times more dopamine to be released into the synapses of the brain, compared to natural rewards. (Amphetamine, for example, can cause a 1,000 percent increase in dopamine levels in animals.) Not only is more dopamine released, but often the reuptake of dopamine into the cells is blocked, meaning that dopamine continues stimulating the brain longer, and stronger, than would a natural reward. The brain then begins to adapt to this level of stimulation. During this stage, drugs also engage the brain’s “habit-forming” centers, which in part explains compulsive substance-seeking behaviors that occur when addicted individuals are exposed to alcohol and/or drug cues in their surroundings.

When the brain adapts to such high levels of stimulation, people develop tolerance to the drug and need more and more of it to get high. And when they can’t get high, they feel awful and begin to use the drug just to feel normal. Individuals often report seeking out drugs not for their positive effects, but for relief of negative symptoms. This stage is called the “negative affect/withdrawal” stage. During this stage, when a person has not used, that person regularly experiences withdrawal symptoms, which can include symptoms of physical illness, nausea, chills, vomiting, irritability, trouble sleeping and eating, and even seizures. It is important to note that withdrawal may occur with any addictive substance, including marijuana, though the actual symptoms vary in intensity and duration depending on the type of substance and the severity of use.

The negative feelings associated with withdrawal are a result both of diminished activity in the reward circuitry of the brain and of activation of the brain’s stress systems in a region called the extended amygdala (which functions to regulate the brain’s reactions to stress—including behavioral responses like “fight or flight,” as well as emotions like fear, anxiety, and irritability). People addicted to drugs will report that as the “wanting” goes up, the “liking” goes down; they don’t ever get the pleasure or high that they did initially. This decreased sensitivity to rewards helps explain the compulsive escalation of substance use, as addicted individuals attempt to regain the pleasurable feelings the reward system once provided. At the same time, the brain begins releasing neurotransmitters such as corticotropin-releasing factor, norepinephrine, and dynorphin, which are released during acute or chronic stress. These stress hormones cause an individual to feel even worse when he or she is not taking the drugs, which, in turn, intensifies the individual’s desire to use, creating a dangerous cycle.

Finally, the third stage of the addiction cycle is known as the preoccupation, or craving, stage. In this stage, obtaining the drug becomes an obsession. Individuals give up other activities, such as school, work, hobbies, and time with family and friends, in order to take the drug. Their entire life is structured around their drug use. Prefrontal brain regions involved in higher-order “executive function,” such as planning, self-control, and attention, are involved in this stage. This stage of the addiction cycle is characterized by a disruption of executive function, which is caused by reduced activity and efficiency in the prefrontal cortex. These prefrontal regions comprise two opposing systems: a “go” system, which helps people make decisions and initiate behaviors, and a “stop” system, which inhibits the activity of the go system. When an individual is addicted to a substance, overactivation of the go system promotes habit-like substance seeking, and underactivation of the stop system promotes impulsive and compulsive substance seeking. The activity of the neurotransmitter glutamate is increased, which drives substance use and disrupts how dopamine influences the frontal cortex. Diminished inhibitory control over behavior, as evidenced by reduced prefrontal cortical activity, drives the individual to compulsively use drugs even in the face of serious negative consequences.

Does Treatment Work?

Once an individual is addicted to any drug, whether it is alcohol or methamphetamine, simply stopping use can be dangerous and even deadly because the brain has chemically adapted to high levels of drug use. A person often needs medical supervision when detoxing from drugs. After detoxification, there are many avenues for treatment.

It is important to note that addiction is incredibly difficult to treat; even with proper treatment, which often consists of a combination of medication, treatment of co-occurring psychiatric conditions, psychological and social interventions, and mutual-help organizations (such as Alcoholics Anonymous (AA)), sustained recovery often can take several years to achieve, and individuals often need multiple episodes of treatment and recovery support. There is still an implicit assumption that a lifelong cure will occur after one episode in “rehab.” However, despite its difficulties, there is no question that treatment works. Rates of relapse to substance use are similar to relapse rates of other chronic diseases, such as hypertension or asthma. Studies of adult populations with chronic and severe substance use disorders show that more than 50 percent will eventually achieve sustained remission, defined as remission that lasted for at least one year. Treatments for substance use disorders are also extremely cost-effective and save society billions of dollars compared to criminal justice costs, lost productivity, and health care costs of an individual who remains addicted to drugs. Neuroscientists have found that at least some brain recovery occurs. Though the amount of brain recovery is still an active area of research, there is some evidence that brain structure (e.g., neuronal density) and brain function (e.g., cognition, memory function) improve within the first few months of sobriety, though, it should be noted, it can take up to two years after cessation of use for neurotransmitter levels to normalize. Treatment can be effective at any stage. Among the public, there is a perception that an individual must hit “rock bottom” in order to finally seek treatment, but the truth is that treatment and prevention efforts can be effective at all levels, from mild to severe substance use disorders. In fact, several studies show that the earlier a clinician intervenes at the first sign of a developing substance use disorder, the better the outcome. Finally, the medical community is now beginning to understand that certain medications can be extremely beneficial, especially when practiced alongside psychosocial interventions. There are currently three approved medications for alcohol dependence and three for opiate dependence, which work by targeting parts of the brain involved in craving or by curbing withdrawal symptoms.

Why Aren’t People Getting the Treatment They Need?

Although treatment works for many people, only 1 in 10 individuals with a substance use disorder ever receives treatment in the first place, leaving a treatment gap of more than 20 million Americans. There are many reasons for this: lack of doctors, lack of insurance/inadequate insurance, insufficient public funds, and stigma. Historically, traditional health care settings failed to recognize or treat addiction. Doctors did not ask about drinking or drug use behaviors, and those patients who volunteered this information would be referred to specialized addiction programs, such as AA. Even today, primary care physicians and psychiatrists rarely treat addiction. Patients with addiction often are referred out of the psychiatric setting and into programs run by non-psychiatrists. When inpatients are admitted to psychiatric units, substance use is often documented, but there is little consultation with the patient or the family about the importance of addiction treatment. Doctors can block dual-diagnosis patients from psychiatric services, arguing that the addiction has to be treated first, before addressing mental health problems. The definition of “addiction” is unclear; some cases of addiction are obvious, but the concept is still vague to some clinicians. Treatment is difficult because of a lack of a uniform approach, and the multifactorial nature of any successful strategy.

Effects of addiction interfere with medications to treat mental health disorders (e.g., when a patient uses drugs or drinks, it affects the response to medications or therapy). During medical school, there are still few required courses in addiction, and only a few states require continuing education in the use of narcotic medications and the management of chronic pain. Because of these issues, there is a tremendous gap between those who seek treatment from physicians and those who receive it. Suboxone®, one of the approved medications for opiate addiction, is an example of a medication that is safe and has been proven to work effectively, but that is not accessible to most people who need it because there aren’t enough Suboxone providers to keep up with demand. In 2016, less than 1 percent of psychiatrists and less than 0.01 percent of primary care physicians were Suboxone providers. Doctors have to undergo specialized training for Suboxone, as well as agree to Drug Enforcement Administration inspections of their practices, and many are afraid of divergence of Suboxone to the black market. And unfortunately, some doctors share the prejudices of the societies they live in, and may blame people with addictions for being immoral, unmotivated, or weak. These issues surrounding Suboxone exist with almost all medications for addiction.

Looking Forward . . .

Things are beginning to change, partially because of the national attention surrounding opioid addiction and partially as a result of ongoing neuroscience studies that have demonstrated the effects of drugs on the brain. Screening for substance misuse is increasingly being provided in general health care settings, and part of the Affordable Care Act provides support for mental health and addiction treatment. These trends will help people with addictions succeed in achieving sustained recovery.

In 2006, the National Institute on Drug Abuse put forth the following principles that are relevant to criminal justice populations: (1) Recovery requires effective treatment and ongoing management/monitoring, (2) treatment must be long enough to produce stable change, (3) drug use should be monitored during treatment, (4) continuity of care is essential on community reentry, and (5) a balance of rewards and sanctions encourages prosocial behavior and treatment participation. These principles make sense when one considers the neuroadaptations that occur during years of cycles of intoxication, withdrawal, and craving. Changes in the brain resulting from addictions may be long-lasting and will not resolve after short periods of abstinence. As we accept that treatment for addiction is lengthy and highly multifactorial, we will undoubtedly see greater successes in conquering addiction.