The Neurobiology of Substance Use, Misuse, and Addiction Surgeon Generals Report on Alcohol, Drugs, and Health

Learn more about substance misuse and how it relates to HIV, AIDS, and Viral Hepatitis. The most severe form of alcohol withdrawal is delirium tremens (DTs), characterized by altered mental status and severe autonomic hyperactivity that may lead to cardiovascular collapse. Only about 5 percent of patients with alcohol withdrawal progress to DTs, but about 5 percent of these patients die. Alcoholism was identified in 1956 as an illness by the American Medical Association (AMA). It’s a disease—an altering of the brain that controls a person’s motivation and ability to make healthy choices.

Group therapy supports people with SUD in maintaining self-control and restraint. According to the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5), a person must have at least two signs in the symptoms section over 12 months to be diagnosed with substance use disorder. It typically involves an overpowering desire to use the substance, increased tolerance to the substance and/or withdrawal symptoms when you stop taking the substance. Because of the addictive nature of opioid use disorder, many people lose control over their behavior. Substances send massive surges of dopamine through your brain, too, as well as certain activities, like having sex or spending money. But instead of motivating you to do the things you need to do to survive (eat, work and spend time with loved ones), such massive dopamine levels can have damaging effects on your thoughts, feelings and behavior.

Reward system

Many addictive substances provide a temporary feeling of pleasure in the person using them. Specifically, addiction is a condition in which a person has come to rely on the use of an addictive substance. Individuals with addiction will continue to abuse addictive substances despite the chaos it creates in their lives. Some substance abuse treatment programs focus mainly on spiritual talk therapy but without tackling the disease’s underlying physiology. Quality addiction treatment programs focus on correcting the neurological imbalances caused by substance dependence.

Every substance has slightly different effects on the brain, but all addictive drugs, including alcohol, opioids, and cocaine, produce a pleasurable surge of the neurotransmitter dopamine in a region of the brain called the basal ganglia; neurotransmitters are chemicals that transmit messages between nerve cells. This area is responsible for controlling reward and our ability to learn based on rewards. They scale back their sensitivity to dopamine, leading to a reduction in a substance’s ability to produce euphoria or the “high” that comes from using it. This is known as tolerance, and it reflects the way that the brain maintains balance and adjusts to a “new normal”—the frequent presence of the substance. However, as a result, users often increase the amount of the substance they take so that they can reach the level of high they are used to. These same circuits control our ability to take pleasure from ordinary rewards like food, sex, and social interaction, and when they are disrupted by substance use, the rest of life can feel less and less enjoyable to the user when they are not using the substance.

Definition of Addiction

Recognizing negative thoughts and learning to change them is part of what makes cognitive behavioral therapy effective. Inpatient centers require you to live there for the duration of your treatment while outpatient centers allow you to go about living your daily life at home and coming in for treatment and therapy. During the rehab process, you will attend meetings and therapy sessions to learn how to avoid letting addiction take over your life again.

Pharmacokinetic properties determine the doses, routes of administration, and frequency of drug use within a given binge episode. For example, comparison of the brain pharmacokinetics of cocaine and of methamphetamine reveals that both reach the brain very rapidly (although cocaine is somewhat faster than methamphetamine) but that cocaine clears out of the brain much faster than methamphetamine (Figure 3). This difference helps explain why cocaine is taken every 30–60 min during a binge, whereas methamphetamine is taken every couple of how to break the addiction cycle hours (Fowler et al, 2008). The importance of pharmacokinetics also helps explain why most abused drugs (with the exception of alcohol) are injected, smoked, or snorted. These routes allow for a much faster delivery of the drug to the brain than when taken orally (Volkow et al, 2000). Pharmacokinetics also help explain why stimulant drugs such as methylphenidate or amphetamine, which also increase dopamine, are not typically perceived as reinforcing when taken orally as prescribed therapeutically (Chait, 1994; Volkow et al, 2001b).

From Drug Use to Drug Abuse

CREB and other intracellular messengers can activate transcription factors, which can change gene expression and produce long-term changes in protein expression, and, as a result, neuronal function. Animals with activated ΔFosB have exaggerated sensitivity to the rewarding effects of drugs of abuse, and ΔFosB may be a sustained molecular ‘switch’ that helps to initiate and maintain a state of addiction (McClung et al, 2004). Whether (and how) such transcription factors influence the function of the brain stress systems, such as CRF and those described above, remains to be determined. The nucleus accumbens is situated strategically to receive important limbic information from the amygdala, frontal cortex, and hippocampus that could be converted to motivational action through its connections with the extrapyramidal motor system.

Such research has the potential to identify common neurobiological mechanisms underlying substance use disorders, as well as other related mental disorders. This research is expected to reveal new neurobiological targets, leading to new medications and non-pharmacological treatments—such as transcranial magnetic stimulation or vaccines—for the treatment of substance use disorders. A better understanding of the neurobiological mechanisms underlying substance use disorders could also help to inform behavioral interventions. Sex differences in reaction to addictive substances are not particular to humans.