Nevertheless, considering that the key action of psychoactive substances is on the brain, it is no surprise that long-term use of drugs or alcohol can result in brain injury. The debilitating and potentially life-threatening results warrant a further understanding of exactly what the risks are, whether or not they can be prevented or reversed, and how to treat them.
Drugs and alcohol have a number of effects on the brain, including:
Different substances induce these effects to different degrees, including the specific drugs discussed below.
One of the ways that substance abuse can result in brain damage is by interfering in the use of nutrients required to maintain brain chemistry. An example of this occurs with alcohol abuse, which can result in thiamine deficiency. Thiamine, one of the B vitamins, is not able to be produced by the body, which means it must be ingested because it is required by nearly all the tissues in the body, including the liver, heart, and brain. However, alcohol interferes with the body’s ability to absorb thiamine, resulting in deficiency.
As described in an article from the National Institute on Alcohol Abuse and Alcoholism, this thiamine deficiency can result in brain injury that includes a combination of Wernicke’s encephalopathy and Korsakoff’s psychosis. This debilitating and potentially deadly neurological condition causes nerve paralysis and mental confusion, as well as an inability to coordinate muscle movement. The thiamine deficiency can also cause brain cell damage that results in incapacitating dementia.
Stimulants like cocaine and methamphetamine have direct action on dopamine and its receptors in the brain, reducing the uptake of the neurotransmitter, which is the source of the extreme euphoria these drugs can cause. However, another result of this action is that, over time, the dopamine receptor cells in the brain can be damaged or even die off, as described in a study from the European Journal of Pharmacology. The result of this brain damage is a condition called anhedonia, which is a diminished ability, or even lack of ability, to feel pleasure if the drug is not being used.
Because this is the result of actual cell death, the lack of ability to feel pleasure can last long after use of the drug is stopped. The follow-up result then can be deep depression, including suicidal thoughts and self-destructive actions. However, with treatment and continued abstinence from the substance, dopamine receptors and capabilities can repair and return to some function.
The development of psychosis has been noted in some individuals who use marijuana regularly; however, the mechanisms through which this happens are not fully understood. Through some research, speculation has risen that this may only occur in people who already have a predisposition toward schizophrenia or other conditions. However, this may not be the whole story.
Many studies have demonstrated a potential lack of damage to the brain due to cannabis use. However, a study discussed by the Schizophrenia Research Institute has found that the hippocampus and amygdala can experience reduction in size due to long-term marijuana use. These two parts of the brain are implicated in schizophrenia.
While the causes of this condition are not fully understood, there are multiple hypotheses about it, including one that optic nerve damage results in inflammation or that an enzyme that supports visual perception is disrupted. Whatever the case, this condition can persist many years after hallucinogen use is stopped.
Depressants like opioids cause suppression of breathing, which in turn can result in decreased blood oxygen concentrations. This can result in a wide range of damage, including oxygen deprivation to the brain. As explained by the National Library of Medicine, lack of oxygen to the brain can directly result in brain cell death and quickly lead to coma.
Hypoxia is often an acute condition brought on by opioid overdose, but it can also accumulate over years of abuse of these drugs, resulting in diminished oxygen to the brain that causes slow-developing damage over time.
Depending on the type of damage, it may be possible to reverse the damage caused by drug or alcohol abuse. By reintroducing missing nutrients or promoting reestablishment of chemical pathways in the brain, early-stage damage can be reversed or at least somewhat repaired. However, in cases of extensive cell death or damage, reversal may not be possible.
The National Institute on Drug Abuse provides hope, noting that treatment and technology advances are helping to improve the chances that lost functions can be recovered after substance abuse is stopped. This includes abilities to reduce cravings that make a person more likely to relapse to substance use and continue contributing to further damage.
The best chance for recovery or reversal depends on intervention as early as possible. Recognizing that substance abuse is occurring is essential to getting on this path. Signs of brain damage due to substance abuse may include:
If these signs are recognized, getting help as quickly as possible can provide the nutritional and other support that can enable the brain and body to recover from the issues.
Addiction has no cure, and in some cases, the damage from abuse of psychoactive substances may not be fully repairable. However, professional, research-based treatment programs provide the most current, demonstrated abilities to treat and manage the issues that arise from addiction. With this type of intervention, the individual has an improved chance of returning to a productive life, along with the ability to manage long-term recovery.