At the time of the National Survey on Drug Use and Health (NSDUH) in 2014, one out of every 10 American adults (aged 12 and older) had used an illicit drug in the previous month. Drugs interact with naturally occurring chemicals in the brain, and virtually all mind-altering substances have some impact on the brain’s reward processing center and pathway. Dopamine is a neurotransmitter, one of the brain’s chemical messengers, used to send signals of pleasure. It is also involved in learning, memory formation, movement and coordination abilities, and attention functions. Typically, when something makes a person feel happy, a signal is sent to the VTA (ventral tegmental area), and it travels to the nucleus accumbens and then to the prefrontal cortex, the National Institute on Drug Abuse (NIDA) explains.The hippocampus then records the memory of this event, and the amygdala creates a conditioned response, encouraging a person to repeat the behavior. Addictive drugs create a shortcut to reward by sending a flood of dopamine to the nucleus accumbens, Harvard Health Publications reports. NIDA publishes that when drugs are abused, they can stimulate 2-10 times more dopamine to be released than things like food or sex may. This flood of dopamine causes a burst of euphoria, or the “high,” that occurs when illicit drugs are abused. It can be highly pleasurable, and individuals are often keen to repeat the feeling with recurring drug use.
Regular drug use actually causes the brain to produce, absorb, or transmit less dopamine, resulting in a chemical imbalance in the brain. When the drugs are not active in the brain, dopamine levels can drop, causing uncomfortable withdrawal symptoms and powerful cravings. Drug dependence sets in, and individuals may feel compelled to keep taking drugs to avoid these negative emotional and physical withdrawal symptoms.
Addiction can then occur quickly, leading to a loss of control over the frequency and amount of drugs taken. The brain will no longer function normally without the drugs, and this imbalance can take time to heal. Much of the damage caused by drug abuse can be reversed with prolonged abstinence; however, some of the side effects may not heal entirely. Behavioral therapies, medications, ongoing support, and other measures that are part of a comprehensive addiction treatment program can help the brain to heal.
Dopamine is one of the brain’s neurotransmitters affected by virtually all drugs of abuse; however, there are many other chemical messengers that can be impacted as well. Some drugs may increase the presence of a particular brain chemical by stimulating its production, while others may block them from being reabsorbed. Neurotransmitters are typically either excitatory or inhibitory, meaning that they either provide stimulation or nervous system depression respectively. As outlined by NIDA, below is a list of neurotransmitters (in addition to dopamine) that are affected by drug abuse, along with their functions in the brain and body and which drugs disrupt their normal transmission, absorption, and/or production:
Serotoninan inhibitory neurotransmitter that works as a mood stabilizer and impacts mood, sexual desire, sleep, and appetite levels
Glutamatethe principle excitatory neurotransmitter in the brain that increases neuron activity and is involved in learning, memory, and cognitive functions
Gamma-aminobutyric acid (GABA)an inhibitory neurotransmitter that lowers stress and anxiety by slowing down heart rate, blood pressure, and body temperature; acts as a natural tranquilizer
Norepinephrinean excitatory neurotransmitter, similar to adrenaline, that activates the “fight-or-flight” stress response in the body; speeds up heart rate, blood pressure, and respiration, and increases body temperature while impacting movement,anxiety levels, sleep, moods, appetite levels, memory functions, and sensory processing abilities
Endorphins and endogenous opioidspeptides that activate opioid receptors in the brain to slow central nervous system functions (including breathing rates), impact mood, and have a sedative and analgesic (painkilling) effect
Endogenous cannabinoidsnon-standard neurotransmitter that interacts with CB1 cannabinoid receptors in the brain, impacting memory, cognitive functions, and movement
Stimulant drugs like cocaine, amphetamines, and methamphetamine stimulate an overproduction of neurotransmitters and may also prevent them from being reabsorbed normally, causing a large amount of these chemical messengers to be present in the brain at once. Drugs like ecstasy (3,4-methalynedioxymethamphetamine) interfere with the regular transmission method of neurotransmitters like serotonin and the way they are transported along natural pathways in the brain, ScienceDaily warns. Other drugs, such as heroin, prescription opioids, and marijuana, actually mimic natural brain chemicals and bind to receptors sites themselves, activating the neurons in their own way and thus disrupting the natural transmission and production of neurotransmitters and brain chemicals. With repeated drug abuse, the brain can actually be rewired as it struggles to keep chemically balanced.
The American Society of Addiction Medicine (ASAM) defines addiction as not only a behavioral disorder, but also as a brain disease that impacts brain chemistry and circuitry and results in compulsive drug-seeking and drug-using behaviors that interfere with daily functioning. A high level of drug dependency, co-occurring medical or mental health disorders, polydrug abuse, family history of addiction, high levels of stress, experience of trauma, and low level of support at home can all contribute to the onset of addiction.
When addiction is present, dopamine, serotonin, and other neurotransmitters affected by drug abuse may no longer be produced, transmitted, and absorbed the way they were before introduction of the drugs. Neurons may be damaged, and the regular functioning of these chemical messengers is impeded. It may then be difficult to feel pleasure from normal and everyday activities. Depression, anxiety, insomnia, irritability, restlessness, trouble with memory and cognitive functions, difficulties regulating moods, and issues controlling cravings may arise without the interaction of drugs.
Many side effects of drugs on brain chemistry can be turned around when the drugs are processed out of the body after a period of time. Some drugs may have a more lasting impact, however. Drugs like methamphetamine may damage as many as half of the dopamine-producing cells (and maybe even more of the nerve cells containing serotonin) in the brain with chronic exposure, the Drug Enforcement Administration (DEA) warns. This damage may only be partially reversible as chronic meth users may suffer from memory problems, learning issues, psychosis, aggression, emotional dysfunction, and even potentially develop Parkinson’s disease as a result of functional and structural changes to the brain that may persist for years after stopping use, NIDA publishes.
Regular cocaine abusers can struggle with impulse control, decision-making, sustaining attention, and performing motor tasks even after achieving abstinence from the drug, NIDA warns. Marijuana can deplete grey matter in the brain, particularly impacting adolescents and young adults whose brains are not fully formed when the drug is introduced, and lead to sustained memory and motivation problems, Psychology Today publishes.
In short, addictive drugs create a dangerous imbalance in the brain that will require comprehensive and specialized treatment to facilitate healing and long-term recovery.
Once the brain has become imbalanced due to drug abuse and dependence, it can take some time and effort to restore things. Cravings and emotional and physical withdrawal symptoms can be significant; with some drugs, they may be dangerous or even life-threatening. The safest method to restore a chemical balance to the brain is through medical detox.
Detox is the process of allowing toxins to make their way out of the brain and body, allowing for proper healing. Medical detox is the most comprehensive form of detox. It provides 24/7 medical and mental health monitoring and supervision in a controlled and secure environment.
Different drugs may process out of the body at variable timelines, and side effects can range greatly in intensity during detox. On average, a person will remain in a medical detox program for several days to a week or two. Medications are often used to counteract withdrawal symptoms and manage drug cravings.
Some drugs, like opioids and benzodiazepines, should not be stopped “cold turkey” and are often either tapered off slowly or replaced with a longer-acting agonist medication during detox, which is then carefully weaned off to minimize withdrawal symptoms. The goal of detox is to help an individual reach a level of physical stabilization and prepare them for admission into an addiction treatment program.
Withdrawal symptoms may continue beyond detox, although the acute nature of the symptoms usually begins to dissipate after this point. The brain can take more time to heal and achieve a healthy balance. NIDA recommends that an individual battling addiction remain in a treatment program for at least 90 days and longer when needed. This allows time for the brain to establish new neural connections, new habits to form, and brain chemistry to be restored.
Behavioral therapies, such as Cognitive Behavioral Therapy (CBT), have been shown to improve brain functioning and connections by modifying negative thoughts and emotions and creating healthier responses to stress. The journal Translational Psychiatry published studies that indicate improvement in brain connections in those suffering from paranoid schizophrenia when they were treated with CBT for psychosis.
Research is beginning to uncover how positive modifications to thought processes may significantly improve brain functions. Often used to treat addiction, CBT improves self-reliance and enhances self-esteem while teaching effective coping mechanisms and measures for preventing relapse when confronted with potential triggers. In therapy, people can learn healthy ways to enhance pleasure and occupy the mind. These methods then help them to maintain ongoing sobriety.