Medical research is drawing connections between some health conditions that may come as a shock to the general public.
What Is Parkinson’s Disease?
At present, it is estimated that 1 million Americans have Parkinson’s disease. A movement disorder, this serious health condition typically worsens over time. It is thought that Parkinson’s disease develops due to the death of neurons in the brain, specifically in the substantia nigra region.
The neurotransmitter dopamine plays a major role in Parkinson’s disease. Dopamine is a key chemical player in a person’s ability to control motion and coordination. Over time, a person with Parkinson’s disease will produce less and less dopamine. The most common symptoms associated with Parkinson’s disease are slow movement, tremors, limb and core body stiffness, and problems balancing.
Clinical Perspectives on Addiction
According to the 2014 National Survey on Drug Use and Health, 21.5 million Americans in the 12+ age group had a substance use disorder in the year prior to the survey. The term addiction has been replaced in the clinical field with the term substance use disorder.
Per the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), a person may be diagnosed with a substance use disorder if at least two delineated symptoms are present in the same 12-month period (referred to in the literature as signifiers or criteria). Per the DSM-5, there are a total of 11 possible symptoms. The more symptoms present, the greater the severity of the substance use disorder. Grading along the substance use disorder continuum ranges from mild to moderate to severe.
How Are Parkinson’s Disease and Substance Use Disorders Linked?
As the Michael J. Fox Foundation notes, the exact cause of Parkinson’s disease is unknown, but there is a consensus that genetics and the environment each play a key role. In terms of genetics, some research supports that Parkinson’s disease can develop due to one genetic mutation of the gene LRRK2. When this is the case, more than one individual in a family with this genetic mutation will develop Parkinson’s disease. Regarding environmental causes, research suggests that the use of certain drugs can set off chemical events in the brain that lead to the onset of Parkinson’s disease or at least the development of symptoms typically associated with this disorder.
This article focuses on some of the illicit drugs that, according to research, may be responsible (at least in part) for the development of Parkinson’s disease-like symptoms. The drugs that will be considered herein are heroin, cocaine, methamphetamine, and amphetamine. While each of these drugs has a different chemical structure, when their component chemical parts are broken down, they affect similar areas of the brain, such as the substantia nigra region.
TIME has reported on one of the most tragic and bizarre but ultimately medically useful set of facts ever to play out in a human interest story. In California, in 1982, a 42-year-old, George Carillo, was admitted to the hospital due to complications related to his recent heroin abuse. The attending emergency room doctors were surprised that Carillo was presenting with symptoms of Parkinson’s disease, a health condition that affects one in every 100 Americans over 60 years of age. It is especially rare to diagnose Parkinson’s disease in a person younger than 50 years of age. In the emergency room, Carillo was mute, drooling, and his muscles appeared to be frozen. These symptoms were shocking to the attending chief neurologist, Dr. J. William Langston. This emergency room visit would in time change the lives of Carillo, Dr. Langston, and countless others affected by Parkinson’s disease.
Dr. Langston was able to find some other individuals who had consumed the same batch of heroin as Carillo, six others in total. They all had similar symptoms. The case got the attention of the nation, specifically Parkinson’s disease researchers and drug abuse specialists. Soon, research revealed that the heroin Carillo consumed contained a chemical known as MPTP, which is chemically close to MPPP, an ingredient in the potent pain reliever Demerol. MPTP caused the brain of the affected heroin users to act similarly to the brains of people with Parkinson’s disease. Stated otherwise, the MPTP attacked the substantia nigra complex in the brain of the heroin users. Again, the substantia nigra is an area that plays a critical role in dopamine production and functionality, and thereby coordination. The symptoms that people with Parkinson’s disease experience, as well as the symptoms that the affected heroin users faced, typically occur when a person loses 80 percent or more of the neurons in the substantia nigra. In short, MPTP radically destroyed the neurons in this area of the brain in the individuals who had consumed the heroin batch at issue.
The affected heroin users were eventually referred to in the media as “frozen” because of the acute stiffness of their limbs. These seven individuals agreed to be studied with the hope that research would develop that would help them. From this case, Parkinson’s disease researchers gained exceptional insights into how to potentially prevent and treat Parkinson’s disease. One theory that arose from research posited that toxins in the environment that are similar to MPTP may be a root cause of Parkinson’s disease.
In 2014, the Michael J. Fox Foundation reported on updates in the case of the “frozen” individuals who had used the dangerous MPTP-involved heroin. Three of the seven had gone to Switzerland to try a breakthrough treatment, but ultimately those medical efforts were not able to reverse the group’s Parkinson’s disease symptoms. As of 2014, only two of the seven were still alive (George Carillo had passed away by this point). Though it came at the cost of most of their lives, the frozen group profoundly helped Parkinson’s disease researchers to learn more about this condition and even helped to pave the way to a possible cure.
According to the 2014 National Survey on Drug Use and Health, an estimated 1.5 million Americans in the 12+ age group were currently using cocaine, including an estimated 354,000 people using crack cocaine. While it may not come as a surprise that cocaine is still a popular drug of abuse, its link to Parkinson’s disease is anything but expected. As discussed in Science Daily, adults who abuse cocaine may face a greater risk of developing Parkinson’s disease. Further, the children of women who abused cocaine while pregnant may experience a greater likely of developing Parkinson’s disease later in life.
The connection between cocaine and Parkinson’s disease works in an unexpected way. Cocaine use weakens the brain complex known as substantia nigra pars compacta (SNpc). This area produces dopamine which, as stated earlier, is a neurotransmitter that plays a critical role in motor coordination and functioning. Deterioration of the SNpc makes the brain more susceptible to harmful toxins like MPTP and a host of others.
In short, cocaine undermines the brain’s ability to fend off attacks from environmental toxins. Certain environmental toxins, once they penetrate the brain, can lead to Parkinson’s disease. Some members of the medical community predict that as cocaine users from the 1980s and 1990s age into senior citizenship, there will be a rise in the number of people with Parkinson’s disease.
Methamphetamine and Amphetamine Abuse and Parkinson’s Disease
The National Institute on Drug Abuse reports that methamphetamine and amphetamine abuse can increase the risk of developing Parkinson’s disease.
A main insight from this research is that abuse of these types of drugs damages dopamine neurons in the brain. As Parkinson’s disease is a dopamine-related disorder, it makes sense that individuals who abuse drugs, and thereby damage their dopamine neurons, may develop symptoms of Parkinson’s disease. Since, as discussed earlier, dopamine plays a key role in muscle coordination and functionality, dopamine damage results in motor impairment, a hallmark of Parkinson’s disease.
One research study found a near 300 percent increase in the risk of developing Parkinson’s disease in people who have abused methamphetamine or amphetamine. This risk is alarming when one considers that despite public knowledge of the devastating effects of methamphetamine abuse, in 2014, an estimated 438,000 Americans in the 26+ age group were currently using this illicit drug. Note that the 2014 National Survey on Drug Use and health, from which this statistic is taken, did not expressly collect data on amphetamine use, so the estimated number of amphetamine abusers for that survey year is not available. When amphetamine abuse does occur, it is often in the form of prescription medications such as Adderall and Ritalin.
A review of the neurological impact of drug abuse and separately, of Parkinson’s disease, opens a window into the very nuanced and delicate workings of brain complexes, like the substantia nigra, as well as critical neurotransmitters, like dopamine. Interestingly, this discussion illuminates how there are different pathways to similar outcomes; a person who never used drugs and develops Parkinson’s disease may experience similar symptoms as a person who has abused certain illicit drugs. If there is one main lesson to be learned from looking at the parallels between substance abuse and Parkinson’s disease, it is that drug abuse can always expose individuals to a host of unexpected and severe consequences.
The good news is that recovery from substance abuse is always possible.
Although the “frozen” individuals who abused heroin were profoundly affected and never restored to their former level of health, they each represent an extreme and unprecedented experience.
Importantly, research into the link between symptoms of Parkinson’s disease and those related to illicit drug abuse can be translated into serious public warnings that may succeed in preventing a person from ever initiating into drug abuse or motivate a person in need of treatment to seek recovery services. Knowing that Parkinson’s disease-like symptoms can emerge, and this disorder is particularly difficult to manage (dopamine replacement is not always effective on a long-term basis), individuals may appreciate the true hazards to their health when they use drugs. Usually, a person is aware of symptoms, or a cluster of symptoms. However, much of the world knows of Parkinson’s disease and its devastating impact on a person’s physical health and quality of life, especially over the long-term as this disease progresses. For this reason, an understanding of the connection between Parkinson’s disease and illicit substance abuse is a particularly powerful message to include in drug education campaigns.