Overcoming drug addiction is difficult because it actually changes the brain. Initially, a person’s choice to consume drugs is voluntary. But with repeated drug use, a person develops a dependence on the sensation of pleasure or behavioral changes created by drugs when they act upon the brain. This is why drug addicts can find it nearly impossible to stop using drugs.
In order to understand the long-term effects of drugs on the human brain, we need to first understand how drugs work.
How Do Drugs Work in the Human Brain?
Drugs alter the way the neurons (nerve cells) inside the human brain send, receive and interpret signals via neurotransmitters such as dopamine. Drugs are particularly known to affect neurotransmitters that regulate the brain’s reward system.
Certain drugs such as heroin and marijuana are able to activate neurons because their chemical structure resembles the neurotransmitters naturally found in the human body. Although various (legal and illegal) drugs mimic the brain’s chemicals, they do not activate neurons in the same manner as a natural neurotransmitter. This ultimately leads to the circulation of abnormal messages through the neural network.
Other drugs such as cocaine and amphetamines are known to force neurons to release natural transmitters in bulk and interfere in their natural recycling mechanism, ultimately amplifying or disrupting the natural communication between the neurons. It is this flood of a natural neurotransmitter such as dopamine that causes the characteristic high achieved after consuming cocaine or amphetamine.
Many scientific studies have found that drug addiction and dependence is a direct outcome of drugs disrupting neurotransmission (communication between neurons). These changes can ultimately affect a person’s speech, judgment, thinking, behavior, concentration, and productivity. As drug abuse in the United States is on the rise, an increasingly large number of organizations, including private employers, have made pre-employment drug screening a necessary component of their hiring processes. Both public and private organizations conduct drug tests in order to promote safer working environment as workers under the influence of drugs can compromise the safety of co-workers, customers, and the public at large.
Parts of the Brain Affected by Repeated Drug Use
- The basal ganglia: A reward-circuit, it plays an important role in how humans form routines and habits; as an important part of the ‘reward system,’ it helps generate positive forms of motivation, including the sense of satisfaction resulting from various healthy activities. With repeated drug use, the ‘reward-system’ regulated by the basal ganglia develops a dependence on the drugs. With insensitive basal ganglia, an addict cannot feel pleasure unless he or she uses drugs.
- The extended amygdala: It’s a stress-circuit that plays a crucial role in feelings such as anxiety and unease, often resembling the stressful feelings experienced during withdrawal. The extended amygdala becomes over-sensitive with continuous drug abuse. With time, an addict needs to consume drugs, not to get high but to be free from stressful feelings.
- The prefrontal cortex: This part of the brain provides humans with the ability to think, analyze, plan, and decide. It also helps a person control his or her urges. Besides the reward-and-stress-circuits, when the prefrontal cortex is off-balance, an addict compulsively seeks drugs with little or no impulse control. The prefrontal cortex is the last part of the brain to mature. Therefore, teens are at a greater risk to experience damage in this part of the brain when they abuse drugs.
Prolonged Drug Use Can Result in Impaired Cognitive Function
Glutamate, a neutron-transmitter involved in the brain’s reward system is also affected by repeated drug use. How the brain attempts to compensate for it changes how a person thinks. It ultimately makes it difficult for a drug addict to think and learn.
Long Term Effects of Opiates on the Human Brain
Opioid or depressant overdose can result in permanent brain damage. Overdoses are more common once an individual’s brain and body develop tolerance to a drug, motivating him or her to take higher dosages. Brain damage normally happens due to retarded respiration and lack of oxygen in the brain. In Calgary, an 18-year-old boy suffered permanent brain damage as he overdosed on a pill that probably contained fentanyl.
Long Term Effects of Benzodiazepine on the Human Brain
Addiction to Benzodiazepine such as Xanax, Valium, diazepam, and alprazolam can severely damage memory and brain atrophy; older people are at a greater risk. These drugs, when overprescribed for treatment of mental health disorders or abused on purpose, can result in enlargement of cerebral ventricles.
Long Term Effects of Stimulants on the Human Brain
Stimulants commonly abused in various parts of the world include amphetamines, methamphetamines, and ADHD (Attention Deficit Hyperactivity Disorder) drugs. Addiction to stimulants can have an adverse effect on the brain’s dopamine (reward) and serotonin systems.
With time, neurotransmitter receptors become inactive resulting in a condition called anhedonia.
An addict affected by this condition cannot feel any pleasure. This condition is more closely related to methamphetamine addiction but can result from other stimulants as well.
Abuse of ADHD prescription stimulants has also been linked with impaired intellectual capability. Often abused by young students, ironically to improve their academic performance, these stimulants can even cause permanent brain impairment. Therefore, it is important that parents learn how to spot drug use.
Long Term Effects of Marijuana on the Human Brain
Marijuana is claimed to be one of the least harmful drugs, especially by the people who use it for medical purposes. However, a study published by the Cambridge University Press suggests that smoking marijuana that has a high concentration of THC (tetrahydrocannabinol) can damage the corpus callosum, a part of the brain that connects the left and right hemispheres.
The corpus callosum aids in neurotransmission and neural coordination across the two sides of the brain. When the corpus callosum is affected by the THC (from high potency marijuana), an individual is at high risk of developing psychosis.
