THE NEUROBIOLOGY OF SUBSTANCE USE, MISUSE, AND ADDICTION Facing Addiction in America NCBI Bookshelf

Relationship between alcoholism, balance with and without use of stabilizing aids, and the cerebellar vermis. Balance testing is conducted using a force platform, which detects sway as people attempt to stand still. Study participants try to maintain quiet balance for 30 seconds under different experimental conditions. When no stabilizing aids can be used, the sway paths are quite long, especially in alcoholics (see stabilograms on the left). With sensory (i.e., vision or light touch) or stance (feet apart) aids, the sway paths are short, even in alcoholics.

• This information is critical for development of alcohol regulation and abuse prevention.
• This makes alcohol and endotoxins more likely to cross the lining of the gut and travel via the circulation to the liver.
• Interactions of the opioid and cannabinoid systems at the receptor level have been observed mainly after chronic morphine treatment.
• An important element in the development of drug addiction is the brain’s attempt to chemically counteract the influences of the drug (i.e., neuroadaptation).

Within the brain, a mix of chemical and electrical processes controls the body’s most basic functions, like breathing and digestion. These processes also control how people react to the multitudes of sounds, smells, and other sensory stimuli around them, and they organize and direct individuals’ highest thinking and emotive powers so that alcohol vs drugs they can interact with other people, carry out daily activities, and make complex decisions. For example, alcohol can cause an alternative form of a gene to be expressed in the memory circuits in flies and people, resulting in changes in dopamine receptors and transcription factors involved in reward signalling and neuronal function.

How an Addicted Brain Works

Through the actions of the neurotransmitter dopamine, the brain become extremely efficient in wanting the drug effects, and eventually becomes imprisoned in the wanting. Nevertheless, the ability of the brain to adapt to changed circumstances always keeps the door open for the possibility of recovery. In response to repeated use of a highly pleasurable experience—drugs, gambling—neurons adjust their wiring to become increasingly efficient at relaying the underlying signals. And neural connection to the brain centers of impulse control and decision-making is weakened. If you do choose to drink, your body’s response to alcohol depends on many factors. These include your age, gender, overall health, body weight, how much you drink, how long you have been drinking and how often you normally drink.

Cannabinoids also open potassium channels of the G protein–regulated inwardly rectifying K+ channel (i.e., GIRK) type in transfected cells17 and have been linked to GIRK channels in the cerebellum. Interestingly, cannabinoid effects on synaptic transmission in the amygdala also appear to implicate GIRK channels (Azad et al. 2003), and GIRK conductances have been implicated in alcohol’s effects (Lewohl et al. 1999). Thus, M-channels and GIRK channels are potential sites of interaction between cannabinoids and alcohol at the postsynaptic level, and amygdala neurons display both M and GIRK currents (Meis and Pape 1998; Womble and Moises 1992). Alcoholism follows a dynamic course, with alternating periods of excessive drinking and sobriety.

Addictive Substances “Hijack” Brain Reward Systems

Developing a thorough understanding of how neurobiological differences account for variation among individuals and groups will guide the development of more effective, personalized prevention and treatment interventions. Additionally, determining how neurobiological factors contribute to differences in substance misuse and addiction between women and men and among racial and ethnic groups is critical. Brain imaging studies in people with addiction show disruptions in the function of both the Go and Stop circuits.35-37 For example, people with alcohol, cocaine, or opioid use disorders show impairments in executive function, including disruption of decision-making and behavioral inhibition.

The metabolism of alcohol itself can also lead directly to neurotoxicity as the metabolite acetaldehyde is toxic and can lead to neurodegeneration. Finally, alcohol can lead to neurotoxicity via the induction of both the central and peripheral immune system, causing damaging levels of inflammation. Many people misuse sedatives because they reduce anxiety, help them to relax, and, in some cases, help them sleep. These drugs can also indirectly affect the reward pathway and cause a euphoric high, especially when taken in high doses. In short, alcohol use during adolescence can interfere with structural and functional brain development and increase the risk for AUD not only during adolescence but also into adulthood. To help clinicians prevent alcohol-related harm in adolescents, NIAAA developed a clinician’s guide that provides a quick and effective screening tool (see Resources below).

How Do Drugs and Alcohol Affect the Brain?

Similarly, cocaine can cause an alternative form of a gene to be expressed in the reward centers of mice, leading them to seek out more cocaine. Together, these results point to how the cannabinoid signaling system could be involved in some of the pharmacological effects of alcohol and a possible function for CB1 in alcohol tolerance and dependence, as discussed below. The eCB system may constitute part of a common brain pathway, mediating reinforcement of alcohol consumption and uncovering how the cannabinoid signaling system may provide a target for the treatment of alcoholism.

This is why it’s important to minimize stress in the beginning stages of treatment and recovery. They found that cocaine affects nerve cells in the limbic system, the most ancient part of the brain and one closely tied to emotions. But rather than bind to a receptor, it interrupts the process of reuptake that terminates the action of dopamine. Cocaine is not only a blocker of dopamine uptake but of the reuptake of serotonin and norepinephrine as well.