Addiction is a complex brain disease and disorder that involves significant changes in the way the brain works. Its links to other mental disorders highlight the need for a comprehensive approach to treatment. With a growing understanding of the neurobiology of addiction and its interconnections with other mental conditions, treatments can be more personalized and effective, offering people a better chance of recovery and a healthier life.
Addiction is a complex condition that affects both the brain and the way people behave. To fully understand it, it is necessary to explore the neurobiology behind the condition, understanding how it alters the way the brain works.
Neuroscience research has shown that addiction is not simply a character flaw or a lack of willpower, but rather a chronic brain disease that involves profound and lasting changes in brain function.
Genetics and heredity play a role in the development of addictions, but susceptibility to addiction is influenced by a combination of genetic, environmental and psychological factors.
Studies suggest that about 40% to 60% of vulnerability to addiction can be attributed to genetic factors. Certain genes are associated with reward mechanisms in the brain, such as the gene that influences dopamine, a neurotransmitter involved in pleasure and reward.
People with a family history of addiction are more likely to develop it. This is because they may inherit a genetic predisposition, as well as growing up in environments where substance use is more common or accepted.
Some people have genetic variations that make their brain reward systems more or less responsive to addictive substances. For example, some people may have lower dopamine receptor activity, which may increase the search for substances that stimulate this activity.
Factors such as social environment, stress, trauma, and availability of substances influence whether a person will develop an addiction. Education, social support, and access to mental health care also play protective roles.
In psychological differences, factors such as impulsivity, seeking out new experiences, and mental disorders (such as anxiety and depression) may increase vulnerability to addiction. People who are less able to cope with stress or have low self-esteem may turn to substances to relieve these feelings.
The first experience with a substance can vary greatly from person to person. Some may not experience pleasure or positive effects and therefore have no motivation to continue using, while others may have a very strong response, which increases the risk of continuing to use.
There are different types of addictions, which can be classified into two main categories: substance addictions and behavioral addictions.
While both share common characteristics, such as loss of control and compulsion, they differ in their causes, manifestations, and treatment approaches.
Substance addictions involve the compulsive use of chemicals that affect both the brain and the body. The most common addictive substances include alcohol, drugs, cigarettes, and prescription medications such as opioids and benzodiazepines.
Each substance acts differently on the nervous system, but they all have in common the ability to alter brain chemistry, which reinforces drinking behavior and creates a vicious cycle that is difficult to break.
For example, alcohol addiction is characterized by an uncontrollable urge to drink, often associated with tolerance, where the person needs to consume more to achieve the same effect, and withdrawal symptoms, such as tremors, nausea and anxiety.
Drug addiction includes substances such as cocaine, heroin and marijuana, which alter brain functions and provide feelings of intense pleasure, but also cause serious health and social problems. Nicotine, found in cigarettes, is extremely addictive and can cause physical dependence, with serious health risks, such as heart disease and cancer.
Substance addictions involve chemical changes in the brain, which can result in physical withdrawal symptoms when the substance is withdrawn. Treatment for these addictions often includes detoxification, therapy and the use of medications to help the body adjust and reduce dependence.
On the other hand, behavioral addictions, also known as process addictions, involve repetitive and compulsive behaviors that are not directly related to substance use. Instead, they are linked to specific actions, such as compulsive shopping, gambling, binge eating, or excessive use of the internet, pornography, or video games.
These behaviors may provide temporary pleasure or alleviate negative emotions such as anxiety or depression, but over time they can have negative consequences, such as financial, emotional, and social problems.
Compulsive shopping addiction, for example, is characterized by the urge to acquire items excessively, even when there is no need for them, leading to debt and stress. Gambling addiction involves an uncontrollable urge to gamble, which often results in serious financial problems and damages relationships.
Eating addiction involves episodes of excessive eating, often as a response to stress, and can result in obesity or eating disorders. Excessive use of the Internet, pornography, or video games can interfere with daily responsibilities, causing social isolation and decreased productivity.
Although behavioral addictions do not involve external substances, they have a significant impact on people’s psychological well-being, affecting their social and financial relationships.
Treatment for these addictions often involves behavioral therapy and psychological support. The main differences between substance addictions and behavioral addictions relate to the origin of the addiction, the physiological impacts, and the treatments required.
The term “addiction” is often described as both a disorder and a disease, depending on the clinical perspective adopted. In the medical context, addiction is usually classified as a disorder.
For example, the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) classifies addictions, such as substance use, under the Substance Use Disorders category.
This term implies that addiction is a mental health problem that leads to a pattern of harmful behavior, such as the inability to control the use of a substance or the compulsion to engage in a specific behavior, such as gambling.
Many health experts and institutions, such as the National Institute on Drug Abuse (NIDA), consider addiction to be a chronic disease of the brain. This view is based on the fact that addiction causes significant changes in the structure and function of the brain, particularly in areas related to reward, impulse control, and decision-making.
As a chronic disease, addiction behaves similarly to other medical conditions, such as diabetes or high blood pressure, that require ongoing management over a lifetime.
The term disorder generally refers to a pattern of symptoms that affect mental and emotional functioning, while disease implies a medical condition that affects the functioning of the body. In the case of addiction, this refers to biological changes in the brain, such as dysregulation of reward systems, that are typical features of this condition.
Viewing addiction as a disorder emphasizes the importance of psychosocial interventions, such as cognitive behavioral therapy (CBT) or support groups, while viewing addiction as a disease suggests the need for medical treatments, such as medication to manage withdrawal symptoms or restore balance to brain chemistry.
From a chronic disease perspective, addiction is a long-term condition that can have periods of remission and relapse, much like other chronic diseases. As a disorder, the focus tends to be more on the behavior and psychological impact, taking into account the context and immediate consequences of the addiction.
When a person engages in addictive substances, such as drugs or alcohol, or behaviors such as gambling, the brain begins to release large amounts of dopamine, a neurotransmitter associated with feelings of pleasure and reward.
This release creates an intense feeling of well-being, which people often seek to replicate. Over time, however, the brain adapts to these large amounts of dopamine and becomes less responsive to it, leading to tolerance. That is, the person needs larger amounts of the addictive substance or behavior to feel the same level of pleasure.
In addicted brains, there are fewer dopamine type-2 receptors. Courtesy National Institute on Drug Abuse, National Institute of Health
Chemicals change the way neurons communicate with each other. These changes cause neurons to make you act in ways you wouldn’t normally. There are three main parts of the brain that are affected by drug use:
The basal ganglia is the part of the brain that motivates us to do healthy activities, like eating or hanging out with friends. Drugs flow into this area of the brain and make people feel really happy. But if you use a drug a lot, the basal ganglia can get used to having the drug around and make it harder to feel pleasure from anything other than the drug.
The enlarged amygdala is what makes you feel stressed or angry. When people use drugs, this part of the brain becomes very sensitive. When your body is used to drugs and you stop, the extended amygdala makes you feel really sick, so people will use drugs again just to get rid of that feeling.
The prefrontal cortex helps you think, make decisions, and control your actions. So when someone uses drugs, this part of the brain becomes less able to make good judgments or intervene to say “no” to a harmful impulse.
The main areas of the brain affected by addiction. Image: The National Institute on Drug Abuse 2019
With continued use, a person can develop dependence, where the brain begins to "need" the substance to function normally. When the substance is withdrawn, the person may experience withdrawal symptoms, such as anxiety, irritability, depression, tremors, and even severe physical symptoms, which makes it extremely difficult to stop without professional help.
Addiction also changes the way a person thinks and acts. Over time, the addict's behavior becomes increasingly impulsive and compulsive, causing the person to seek out the addictive substance or behavior, even knowing the negative consequences of doing so.
These changes make addiction a difficult condition to overcome, often requiring professional intervention and ongoing support.
Addiction rarely occurs in isolation. It is often associated with other mental disorders, a condition called "comorbidity." Understanding this association is vital to providing effective treatment.
Depressive and anxiety disorders are commonly found in people with addictions. Some people may use substances as a form of self-medication to relieve symptoms of depression or anxiety. However, substance use can worsen these symptoms in the long run, creating a vicious cycle that is difficult to break.
People with bipolar disorder may turn to substance use to cope with extreme mood swings. This can lead to patterns of substance abuse that further complicate the diagnosis and treatment of bipolar disorder.
Post-traumatic stress disorder (PTSD): Many people with PTSD turn to drugs or alcohol as a way to cope with traumatic memories and flashbacks. However, substance abuse can worsen PTSD symptoms, including increased anxiety and depression.
Obsessive-compulsive disorder (OCD) and impulse control disorders: Addiction shares features with OCD and other impulse control disorders, such as the compulsion to repeat behaviors to relieve anxiety. This overlap suggests that the same brain circuits may be involved in both disorders.
The relationship between addiction and other mental disorders highlights the importance of integrated treatment that involves behavioral therapies and medication appropriate for each disorder, as well as participation in social support groups. This support is particularly important for those struggling with the loneliness and isolation often associated with addiction.
Finally, with a growing understanding of the neurobiology of addiction and its interconnections with other mental health conditions, treatments can be more personalized and effective, offering people a better chance of recovery and a healthier life.
READ MORE:
The neurobiology of addiction
George R Uhl, George F Koob, and Jennifer Cable
Ann N Y Acad Sci. 2019 Jan 15;1451(1):5–28.
doi: 10.1111/nyas.13989
Abstract:
Substance and alcohol use disorders impose large health and economic burdens on individuals, families, communities, and society. Neither prevention nor treatment efforts are effective in all individuals. Results are often modest. Advances in neuroscience and addiction research have helped to describe the neurobiological changes that occur when a person transitions from recreational substance use to a substance use disorder or addiction. Understanding both the drivers and consequences of substance use in vulnerable populations, including those whose brains are still maturing, has revealed behavioral and biological characteristics that can increase risks of addiction. These findings are particularly timely, as law‐ and policymakers are tasked to reverse the ongoing opioid epidemic, as more states legalize marijuana, as new products including electronic cigarettes and newly designed abused substances enter the legal and illegal markets, and as “deaths of despair” from alcohol and drug misuse continue.
Abnormal Brain Structure Implicated in Stimulant Drug Addiction
KAREN D. ERSCHE , P. SIMON JONES, GUY B. WILLIAMS, ABIGAIL J TURTON, TREVOR W. ROBBINS, AND EDWARD T. BULLMORE
SCIENCE, Vol 335, Issue 6068, pp. 601-604
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