Substance Use Disorders Increase Risk for Death From COVID-19

Carla Nieto Martínez

April 19, 2022

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

This article was originally published in Spanish on Medscape.

MADRID, Spain — Individuals with substance use disorders are at higher risk of being infected by and dying from COVID-19 — even if they are fully vaccinated — compared with the general population. Such are the findings of a line of research led by Mexican psychiatrist Nora Volkow, MD, director of the US National Institute on Drug Abuse (NIDA).

A pioneer in the use of brain imaging to investigate how substance use affects brain functions and one of Time magazine's "Top 100 People Who Shape Our World," she led the Inaugural Conference at the XXXI Congress of the Spanish Society of Clinical Pharmacology, "Drugs and Actions During the Pandemic." Volkow spoke about the effects that the current health crisis has had on drug use and the social challenges that arose from lockdowns. She also presented and discussed the results of studies being conducted at NIDA that "are aimed at reviewing what we've learned and what the consequences of COVID-19 have been with respect to substance abuse disorder."

As Volkow pointed out, drugs affect much more than just the brain. "In particular, the heart, the lungs, the immune system — all of these are significantly harmed by substances like tobacco, alcohol, cocaine, and methamphetamine. This is why, since the beginning of the pandemic, we've been worried about seeing what consequences SARS-CoV-2 was going to have on users of these substances, especially in light of the great toll this disease takes on the respiratory system and the vascular system."

Pulmonary "Predisposition" and Race

Volkow and her team launched several studies to get a more thorough understanding of the link between substance abuse disorders and poor COVID-19 prognoses. One of them was based on analyses from electronic health records in the United States. The purpose was to determine COVID-19 risk and outcomes in patients based on the type of use disorder (for example, alcohol, opioid, cannabis, cocaine).

"The results showed that regardless of the drug type, all users of these substances had both a higher risk of being infected by COVID-19 and a higher death rate in comparison with the rest of the population," said Volkow. "This surprised us, because there's no evidence that drugs themselves make the virus more infectious. However, what the results did clearly indicate to us was that using these substances was associated with behavior that put these individuals at a greater risk for infection," Volkow explained.

"In addition," she continued, "using, for example, tobacco or cannabis causes inflammation in the lungs. It seems that, as a result, they end up being more vulnerable to infection by COVID. And this has consequences, above all, in terms of mortality."

Another finding was that, among patients with substance use disorders, race had the largest effect on COVID risk. "From the very start, we saw that compared with white individuals, Black individuals showed a much higher risk of not only getting COVID, but also dying from it," said Volkow. "Therefore, on the one hand, our data show that drug users are more vulnerable to COVID-19 and, on the other hand, they reflect that within this group, Black individuals are even more vulnerable."

In her presentation, Volkow drew particular attention to the impact that social surroundings have on these patients and the decisive role they played in terms of vulnerability. "It's a very complex issue, what with the various factors at play: family, social environment.... A person living in an at-risk situation can more easily get drugs or even prescription medication, which can also be abused."

The psychiatrist stressed that when it comes to addictive disorders (and related questions such as prevention, treatment, and social reintegration), one of the most crucial factors has to do with the individual's social support structures. "The studies also brought to light the role that social interaction has as an inhibitory factor with regard to drug use," said Volkow. "And indeed, adequate adherence to treatment requires that the necessary support systems be maintained."

In the context of the pandemic, this social aspect was also key, especially concerning the high death rate among substance use disorder patients with COVID-19. "There are very significant social determinants, such as the stigma associated with these groups — a stigma that makes these individuals more likely to hesitate to seek out treatment for diseases that may be starting to take hold, in this case COVID-19."

On that note, Volkow emphasized the importance of treating drug addicts as though they had a chronic disease in need of treatment. "In fact, the prevalence of pathologies such as hypertension, diabetes, cancer, and dementia is much higher in these individuals than in the general population," she said. "However, this isn't widely known. The data reflect that not only the prevalence of these diseases, but also the severity of the symptoms, is higher, and this has a lot to do with these individuals' reticence when it comes to reaching out for medical care. Added to that are the effects of their economic situation and other factors, such as stress (which can trigger a relapse), lack of ready access to medications, and limited access to community support or other sources of social connection."

Opioids and COVID-19

As for drug use during the pandemic, Volkow provided context by mentioning that in the United States, the experts and authorities have spent two decades fighting the epidemic of opioid-related drug overdoses, which has caused many deaths. "And on top of this epidemic — one that we still haven't been able to get control of — there's the situation brought about by COVID-19. So, we had to see the consequences of a pandemic crossing paths with an epidemic."

The US's epidemic of overdose deaths started with the use of opioid painkillers, medications which are overprescribed. Another issue that the United States faces is that many drugs are contaminated with fentanyl. This contamination has caused an increase in deaths.

"In the United States, fentanyl is everywhere," said Volkow. "And what's more concerning: almost a third of this fentanyl comes in pills that are sold as benzodiazepines. With this comes a high risk for overdose. In line with this, we saw overdose deaths among adolescents nearly double in 1 year, an increase which is likely related to these contaminated pills. It's a risk that's just below the surface. We've got to be vigilant, because this phenomenon is expected to eventually spread to Europe. After all, these pills are very cheap, hence the rapid increase in their use."

To provide figures on drug use and overdose deaths since the beginning of the pandemic, Volkow referred to COVID-19 data provided by the National Center for Health Statistics (NCHS) at the US Centers for Disease Control and Prevention (CDC). The data indicate that of the 70,630 drug overdose deaths that occurred in 2019, 49,860 involved opioids (whether prescribed or illicit). "And these numbers have continued to rise, so much so that the current situation can be classified as catastrophic — because this increase has been even greater during the pandemic due to the rise in the use of all drugs," said Volkow.

Volkow referred to an NCHS study that looked at the period between September 2020 and September 2021, finding a 15.9% increase in the number of drug overdose deaths. A breakdown of these data shows that the highest percentage corresponds to deaths from "other psychostimulants," primarily methamphetamines (35.7%). This category is followed by deaths involving synthetic opioids, mostly illicit fentanyl (25.8%), and deaths from cocaine (13.4%).

"These figures indicate that, for the first time in history, the United States had over 100,000 overdose deaths in 1 year," said Volkow. "This is something that has never happened. We can only infer that the pandemic had a hand in making the overdose crisis even worse than it already was."

As Volkow explained, policies related to handling overdoses and prescribing medications have been changed in the context of COVID-19. Addiction treatment consequently has been provided through a larger number of telehealth services, and measures such as greater access to treatment for comorbid conditions, expanded access to behavioral treatments, and the establishment of mental health hotlines have been undertaken.

Children's Cognitive Development

Volkow also spoke about another of NIDA's current subjects of research: the role that damage or compromise from drugs has on the neural circuits involved in reinforcement systems. "It's important that we make people aware of the significance of what's at play there, because the greatest damage that can be inflicted on the brain comes from using any type of drug during adolescence. In these cases, the likelihood of having an addictive disorder as an adult significantly increases."

Within this framework, her team has also investigated the impact of the pandemic on the cognitive development of infants under 1 year of age. One of these studies was a pilot program in which pregnant women participated. "We found that children born during the pandemic had lower cognitive development: n = 112 vs n = 554 of those born before January 2019."

"None of the mothers or children in the study had been infected with SARS-CoV-2," Volkow explained. "But the results clearly reflect the negative effect of the circumstances brought about by the pandemic, especially the high level of stress, the isolation, and the lack of stimuli. Another study, currently in preprint, is based on imaging. It analyzed the impact on myelination in children not exposed to COVID-19 but born during the pandemic, compared with pre-pandemic infants. The data showed significantly reduced areas of myelin development (P < .05) in those born after 2019. And the researchers didn't find significant differences in gestation duration or birth weight."

The longitudinal characteristics of these studies will let us see whether a change in these individuals' social circumstances over time also brings to light cognitive changes, even the recovery of lost or underdeveloped cognitive processes, Volkow concluded.

Volkow has disclosed no relevant financial relationships.

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