Mind-altering drugs may slow down or speed up the central nervous system and autonomic functions necessary for living, such as blood pressure, respiration, heart rate, and body temperature. Levels of some of the brain’s chemical messengers, or neurotransmitters, are also impacted by drug abuse, including:
Dopamine: This neurotransmitter regulates moods, enhances pleasure, and is involved with movement, reward and reinforcing behaviors, motivation, and attention.
Serotonin: This neurotransmitter is responsible for stabilizing moods and regulating emotions.
Gamma-aminobutyric acid (GABA): GABA acts as a natural tranquilizer, mitigating the stress response and lowering anxiety levels as well as slowing down functions of the central nervous system.
Norepinephrine: Similar to adrenaline, norepinephrine is often called the “stress hormone,” as it speeds up the central nervous system in response to the “fight-or-flight” response. It also homes focus and attention while increasing energy levels.
Regions of the brain are disrupted by drug abuse, as the National Institute on Drug Abuse (NIDA) reports that the brain stem, limbic system, and cerebral cortex are all affected. The brain stem controls life-sustaining functions, including sleeping, breathing, and heart rate, while the limbic system holds the brain’s reward circuitry and helps to control emotions and the ability to feel happiness. The cerebral cortex is considered the “thinking center” of the brain, managing problem-solving, planning, and decision-making abilities as well as helping people to process information provided by their senses. The more often drugs are used, the more they will impact brain chemicals and circuitry, which can lead to drug dependence and withdrawal symptoms when the drugs process out of the body. Drug cravings, dependence, and withdrawal symptoms, coupled with a loss of control over use, are signs of addiction. The American Society of Addiction Medicine (ASAM) defines addiction as a disease affecting brain chemistry and circuitry, which then leads to compulsive drug-seeking and using behaviors. In 2014, nearly 22 million Americans battled addiction, NSDUH reports.
Synthetic marijuana, also known as Spice or K2, acts on the brain in a similar fashion to the marijuana but to a greater extent. These drugs have been manufactured to be more potent and may then be more active in the brain than the naturally occurring form. Synthetic cannabinoids are generally full agonists at cannabinoid receptor type-1, or CB1, receptors in the brain whereas pot is only a partial agonist. These drugs may be 100 or more times potent than the THC found in natural marijuana, Forbes warns. The journal World Psychiatry reports that there are over 200 forms of synthetic cannabinoids marketed today. Each may have a slightly different chemical or molecular structure and can have unpredictable effects on the brain and body.
Heroin and prescription opioid drugs like OxyContin (oxycodone), Vicodin (acetaminophen/hydrocodone), fentanyl, methadone, and Dilaudid (hydromorphone) bind to opioid receptors in the brain and trigger the release of dopamine. In a sense, these drugs hijack the limbic system in the brain, inducing a powerful high that individuals are often keen to recreate, leading to reinforcing behaviors. Opioid drugs are considered highly addictive, as ASAM publishes that almost a quarter of heroin users will suffer from addiction to opioids. Over 2.5 million Americans battled opioid addiction in 2015. Heroin is considered the fastest-acting opioid, taking effect nearly immediately and making it extremely addictive, the Drug Enforcement Administration (DEA) warns. When someone takes an opioid drug repeatedly, they can develop a tolerance to it as the body gets used to its interaction in the brain. Individuals may then take more of the drug to feel the desired effects. The brain will then stop functioning as it did before introduction of the opioid, causing levels of dopamine to drop when the drug wears off.
Dependence on opioids can form rather quickly. Physical withdrawal symptoms may resemble the flu, and emotional withdrawal symptoms include depression, anxiety, and insomnia.
Benzodiazepine drugs are prescription sedatives and tranquilizers, such as Valium (diazepam), Ativan (lorazepam), Xanax (alprazolam), and Klonopin (clonazepam). These drugs are prescribed to treat anxiety, to relieve muscle tension, and as sleep aids. They serve to increase levels of GABA in the brain and slow functions of the central nervous system. They are commonly misused, however, and can have a euphoric effect when taken in large doses.
Regular use of them, even when taken as directed through a valid prescription, can cause tolerance to develop, requiring escalating dosages. Higher doses, or using the drugs in a manner other than intended (e.g., crushing tablets to snort, smoke, or inject the powder; chewing tablets; or taking too many at once) can lead to extreme confusion, impaired reflexes and coordination, coma, and death. Mixing a benzodiazepine with alcohol, opioids, or other central nervous system depressants greatly increases the risk for a life-threatening overdose.
The prescribing information published by the U.S. Food and Drug Administration (FDA) for Xanax warns that it is not to be taken as a long-term solution since the drug can lead to physical and psychological dependence when taken in doses higher than 4 mg/day for more than 12 weeks. After a dependence on a benzodiazepine has formed, the brain can experience a rebound effect when the drug leaves the bloodstream. The central nervous system that was dampened by the benzo can go into overdrive, and the brain may be slow to produce GABA on its own, which can result in elevated anxiety, depression, trouble sleeping, tremors, suicidal tendencies, sweating, hypertension, irregular heart rate, muscle tension and aches, nausea and vomiting, and even potentially life-threatening seizures. These drugs have such an impact on the central nervous system and brain function that they should not be discontinued suddenly once a dependence has formed. Instead, they are generally tapered off gradually, with the dosage being slowly lowered over a safe period of time. Medical supervision is required for safe withdrawal.
Ecstasy, also known as Molly or by its chemical name, MDMA, is a popular club and psychoactive drug. It binds to serotonin transporters in the brain and has both stimulant and hallucinogenic properties. Within about an hour after ecstasy enters the bloodstream, it stimulates the activity of serotonin, norepinephrine, and dopamine, NIDA explains. Ecstasy stimulates a sense of emotional closeness and warmth, while enhancing and distorting the senses, heightening energy levels, decreasing anxiety, and increasing feelings of pleasure. Heart rate, body temperature, and blood pressure are also elevated by ecstasy use. Hyperthermia, high blood pressure, panic attacks, faintness, involuntary teeth clenching, blurred vision, nausea, sweating, chills, arrhythmia, heart failure, kidney failure, dehydration, loss of consciousness, and seizures are possible side effects of ecstasy abuse and/or overdose. Ecstasy is also commonly combined with alcohol or other drugs, or “cut” with toxic substances, which can have potentially hazardous consequences. Molly, often heralded as the “pure” form of ecstasy, may contain any number of adulterants or chemicals that can have toxic effects, NBC News warns.If a person takes additional doses of MDMA while the drug is still in the system, it can interfere with the metabolism, which can make the cardiovascular and toxic side effects worse, NIDA warns. While the majority of the side effects of MDMA wear off in a few hours, confusion and anxiety can last up to a week after taking ecstasy. MDMA interferes with the way the brain processes information and stores memories, and with long-term use, these cognitive issues can become more pronounced. Anxiety, irritability, sleep difficulties, depression, aggression, impulsivity, loss of appetite, and decreased interest in sex may be side effects of regular ecstasy use. Ecstasy may also be psychologically addictive, leading to withdrawal symptoms when the drug isn’t taken.
A class of drugs that leads to distortions of reality and perceptions, hallucinogens are typically broken down into two main categories: classic hallucinogens (LSD, peyote, psilocybin, DMT, Ayahuasca) and dissociative drugs (PCP, salvia, DXM, ketamine), per NIDA. It is not certain exactly how these drugs work in the brain; however, it is largely understood that they interrupt normal communication between neurotransmitters. Dissociative drugs are believed to disrupt the action of glutamate, a brain chemical that is involved with memories, cognition, emotions, and how people perceive pain. PCP interacts with dopamine as well, while salvia activates the kappa opioid receptor present on nerve cells, per NIDA. Dissociative drugs can make people feel separate from themselves, their environment, and reality. This can result in impaired motor functions, auditory and visual distortions, memory loss, anxiety, numbness, and body tremors.