Implications of Long-Term Drug Use on the Brain

    It’s an undeniable fact that the advent of modern drugs and medicine has profoundly affected the quality and longevity of human life. The branch of medicine concerned with the uses, effects, and modes of action of drugs is called pharmacology. A drug can be defined as any artificial, natural, or endogenous molecule with a measurable biochemical or physiological effect on a cell, tissue, organ, or organism. Pharmacology strongly overlaps with medicine and has been studied for at least several thousand years. Only in the last 200 or so, however, have we been capable of understanding drug action at a molecular level. Many drugs must affect the interactions of neurons directly, with varying severity, to exert an effect on the body. Despite having a general understanding of how a drug might interact with the body, less is understood about the long-term effects of drugs that act on the brain.

    Brain-altering chemicals have a long history in shamanistic cultures and more, but we won't explore those. The more widespread use of these substances to alter behavior or pathways in the brain is a more recent event. Before chemical restraints (thorazine) were invented in the 1950s, the only way to restrain a patient was physically. Since then, hundreds of thousands of molecules have been developed and discovered that have a discernible effect on the brain. 70 years is a relatively short period of time to study the long-term effects of mind-altering substances on the brain. It is a well-observed and accepted phenomenon that neurons constantly make new and varied connections. A large number of patients suffering from neurological or psychiatric disorders—depression, chronic pain, and post-traumatic stress disorder among them—are resistant to or can develop resistance to standard practices. Neurostimulation refers to direct stimulation and modification of the nervous system through the use of electrical, chemical, or mechanical signals. Neurostimulation therapy is already used to treat many brain disorders, most commonly movement disorders, chronic pain, and depression (Penttila 2022). These are examples of the positive use of drugs on the brain, but what are the long-term effects of modification of the nervous system?

    Environment, psychosocial, and psychotherapy are inextricably linked to the concept of the mind, while genes, biology, and medication are often associated with the brain. Recent research, however, suggests that the mind and brain are intimately connected and that clinical work with personality disorders can be best understood through understanding the languages of both the mind and brain in treatment. Psychotherapy has a well-established effect on the brain, and our understanding of psychosocial stressors, like trauma, has been shown to have profound effects on the biological nature and function of the brain. Therefore, separating the concepts of the mind and brain in threatening patients with personality disorders may not be in their best interests. Recognizing that the “theory of mind,” the ability to recognize that someone else has a different mind from one’s own, is essential in the treatment of patients. Just as psychosocial factors produce biological changes over time in the brain, so too do medications and psychotherapy work synergistically to make changes in the brain. Both, then, are necessary in the treatment of personality disorders and in understanding long-term neurological changes.

    Addiction is the compulsive use of a drug despite any cost to health, family, or social standing. Abuse of psychoactive drugs that mimic or increase the presence of certain neurotransmitters can result in addiction, which changes the structure and chemistry of the brain over time, leading to dependency and behavioral changes (NIH 2022). The cause and treatment of addiction is an ongoing and growing field of study. Many advances have changed our views and our response to addiction; particularly impactful have been the discoveries in brain chemistry and its effect on behavior. In the past, addiction was misconceived as the result of a lack of discipline and moral character, which led it to be treated with punishment rather than prevention. Today, we know that addiction is a medical disorder of the brain that affects behavior, rather than a moral failing of individual choice. Many environmental and biological factors have been identified as contributors to the risk and development of addiction, but ongoing is the search to understand genetic factors that contribute to the progression of addiction (NIH 2021). Prevention and treatment of addiction have advanced substantially in an effort to reduce the toll drug use has on individuals, families, and communities, but there are still many unknowns. Why do some individuals have a higher propensity for developing an addiction to drugs? How do drugs change brain chemistry in a way that compels drug use?

    Drug dependence is just one example of the long-term effects of drug use on the brain, but there are many observed examples. Understanding the mechanisms and causes of addiction may help us understand and predict how and why temporary changes in brain chemistry can lead to life-long behavioral changes.

References

National Institutes of Health, “Addiction Science.” U.S. Department of Health and Human Services, 8 Aug. 2022, https://nida.nih.gov/research-topics/addiction-science.

National Institutes of Health, “Drug Addiction.” U.S. Department of Health and Human Services, 3 Aug. 2021, https://nida.nih.gov/publications/drugs-brains-behavior-science-addiction/preface.

Penttila, Nicky. “Rewiring the Brain: Zapping with Precision.” Dana Foundation, 6 Sept. 2022