How does vaping affect mental health. What is the link between nicotine and depression. Can e-cigarettes worsen anxiety symptoms. Are there connections between vaping and ADHD.

The Alarming Connection Between Vaping and Depression

Recent studies have uncovered troubling links between vaping, nicotine use, and mental health issues, particularly depression. A comprehensive 2019 JAMA study involving nearly 30,000 adult e-cigarette users revealed startling statistics:

• Current e-cigarette users have double the odds of being diagnosed with depression compared to non-users
• Frequent vapers face even higher odds – 2.4 times more likely to have a depression diagnosis
• Both current and former e-cigarette users reported more days of poor mental health compared to those who never vaped

These findings raise serious concerns about the impact of vaping on mental well-being. Are e-cigarettes directly causing depression? While a direct causal relationship hasn’t been established, the strong correlation suggests that vaping may exacerbate existing mental health issues or contribute to the development of new ones.

The Role of Trace Metals in Vape Liquids

Researchers have proposed an intriguing theory to explain the potential link between vaping and depression. Could trace metals in vape liquids be playing a role? Some studies suggest that these metallic components might have neurological effects, potentially influencing mood and mental health. This hypothesis underscores the need for further research into the long-term impacts of e-cigarette use on brain chemistry and function.

Vaping’s Impact on Adolescent Mental Health

The effects of vaping on mental health appear to be particularly pronounced in younger populations. A 2017 study focusing on ninth-grade students in Los Angeles yielded concerning results:

• Students who used e-cigarettes more frequently showed higher levels of depressive symptoms
• These symptoms included feelings of sadness and increased likelihood of crying spells
• The negative effects were observed even a year after initial e-cigarette use

These findings highlight the vulnerability of adolescent brains to the effects of nicotine and other vaping components. How does vaping specifically affect developing brains? The study suggests that exposure to e-cigarettes during crucial developmental stages may alter emotional regulation and increase susceptibility to mood disorders.

The Vicious Cycle of Vaping and Depression

One particularly troubling aspect of the vaping-depression connection is the potential for a self-reinforcing cycle. Individuals experiencing depressive symptoms may turn to vaping as a coping mechanism, only to find that continued use exacerbates their mental health issues. This cycle can be difficult to break, emphasizing the importance of early intervention and education about the risks of e-cigarette use.

Vaping and Anxiety: A Growing Concern

Depression isn’t the only mental health concern associated with vaping. Mounting evidence suggests a strong link between e-cigarette use and increased anxiety symptoms. A 2019 study focusing on college students revealed:

• Vaping is significantly associated with higher levels of anxiety symptoms
• Nicotine dependence correlates with greater anxiety severity
• The relationship between vaping and anxiety appears to be dose-dependent

These findings raise important questions about the nature of the relationship between vaping and anxiety. Does nicotine directly contribute to anxiety symptoms, or are anxious individuals more likely to turn to vaping as a coping mechanism? The answer likely involves a complex interplay of biological, psychological, and social factors.

The Role of Nicotine in Anxiety

Nicotine’s effects on the brain may help explain its connection to anxiety. As a stimulant, nicotine can increase heart rate, blood pressure, and alertness – physical sensations that can mimic or exacerbate anxiety symptoms. Additionally, the cycle of nicotine cravings and withdrawal can create its own form of anxiety, further complicating the relationship between vaping and mental health.

The ADHD-Vaping Connection: Unraveling the Relationship

Attention-Deficit/Hyperactivity Disorder (ADHD) is another mental health condition that has been linked to increased rates of vaping and nicotine use. The 2019 study of college students not only found associations with anxiety but also revealed:

• Vaping is significantly associated with higher levels of ADHD symptoms
• Individuals with ADHD may be more likely to initiate and continue vaping
• Nicotine may be used as a form of self-medication for ADHD symptoms

These findings prompt important questions about the nature of the ADHD-vaping relationship. Are individuals with ADHD more susceptible to nicotine addiction? Or does vaping potentially exacerbate ADHD symptoms? The answer likely involves a complex interplay of factors, including shared genetic vulnerabilities and the effects of nicotine on attention and impulse control.

The Self-Medication Hypothesis

One theory proposed to explain the higher rates of vaping among individuals with ADHD is the self-medication hypothesis. This suggests that people with ADHD may turn to nicotine as a way to manage their symptoms, as it can have short-term effects on focus and attention. However, this approach can lead to addiction and may ultimately worsen ADHD symptoms in the long run.

The Dual Threat: Vaping Both Nicotine and THC

Recent research has uncovered a particularly concerning trend: the practice of vaping both nicotine and THC (the psychoactive component in marijuana). A study of over 2,500 individuals aged 13-24 revealed alarming statistics:

• Dual vapers (those who use both nicotine and THC) reported higher rates of anxiety symptoms, depressive symptoms, and suicidal thoughts compared to non-vapers
• Approximately 60% of nicotine-only, THC-only, and dual vapers reported experiencing anxiety symptoms, compared to 40% of non-vapers
• Over half of all vapers reported symptoms of depression, versus only 25% of non-vapers

These findings highlight the compounded risks associated with using multiple substances through vaping. How does the combination of nicotine and THC affect mental health? While more research is needed, it’s clear that this dual use pattern is associated with significantly higher rates of mental health concerns.

The Unique Risks of THC Vaping

While nicotine vaping alone carries significant mental health risks, the addition of THC introduces new concerns. THC can have powerful effects on mood and cognition, and its use during adolescence and young adulthood may have long-lasting impacts on brain development. The combination of nicotine and THC may create a particularly potent risk for mental health issues.

Breaking the Cycle: The Benefits of Quitting Vaping

Given the strong associations between vaping and various mental health issues, quitting e-cigarette use is a crucial step in improving overall well-being. Research has shown that cessation of nicotine use can have significant positive effects on mental health:

• A 2014 meta-analysis found that quitting smoking is linked with lower levels of anxiety, depression, and stress
• Individuals who quit reported improved mood and quality of life compared to those who continued smoking
• The mental health benefits of quitting appear to be long-lasting and may continue to improve over time

These findings underscore the importance of both preventing vaping initiation and supporting those who wish to quit. How can individuals successfully quit vaping and improve their mental health? A combination of strategies, including behavioral support, nicotine replacement therapy, and addressing underlying mental health concerns, may be most effective.

Resources for Quitting

Fortunately, there are many resources available for those seeking to quit vaping. Organizations like Truth Initiative offer free and anonymous quit resources, such as their “This is Quitting” program, which has helped over 350,000 individuals on their journey to quit vaping. Text-based support services, like texting “DITCHVAPE” to 88709, can provide convenient and accessible help for those looking to break free from nicotine addiction.

The Importance of Early Intervention and Education

Given the significant mental health risks associated with vaping, early intervention and education are crucial. Prevention efforts should focus on:

• Educating young people about the potential mental health consequences of vaping
• Addressing misconceptions about the safety of e-cigarettes
• Providing support and resources for those already struggling with nicotine addiction
• Implementing policies to reduce access to and marketing of e-cigarettes to youth

By taking a proactive approach to vaping prevention and cessation, we can help mitigate the mental health impacts of this growing epidemic. How can schools, healthcare providers, and communities work together to address this issue? Collaborative efforts that combine education, policy changes, and accessible support services may be the most effective way to combat the vaping crisis and protect mental health.

The Role of Mental Health Professionals

Mental health professionals have a crucial role to play in addressing the intersection of vaping and mental health. By screening for e-cigarette use among their patients, particularly adolescents and young adults, they can identify those at risk and provide targeted interventions. Additionally, mental health treatment plans should consider the potential impact of vaping on symptoms and recovery, addressing nicotine addiction as part of a comprehensive approach to mental health care.

Future Research Directions: Unraveling the Complexities

While the current body of research has shed light on the connections between vaping and mental health, many questions remain unanswered. Future studies should focus on:

• Longitudinal research to better understand the long-term mental health impacts of vaping
• Investigating the specific mechanisms by which nicotine and other vaping components affect brain function and mental health
• Exploring the potential differences in mental health impacts between various types of e-cigarettes and vaping liquids
• Developing and testing targeted interventions for individuals with co-occurring mental health issues and nicotine addiction

By continuing to investigate these areas, researchers can provide valuable insights that will inform prevention, treatment, and policy efforts. What role will emerging technologies and methodologies play in advancing our understanding of vaping and mental health? From neuroimaging studies to genetic research, new approaches may offer unprecedented insights into the complex relationship between e-cigarette use and psychological well-being.

The Need for Interdisciplinary Collaboration

Given the multifaceted nature of the vaping-mental health connection, interdisciplinary collaboration will be essential in future research efforts. Bringing together experts from fields such as neuroscience, psychology, public health, and addiction medicine can provide a more comprehensive understanding of the issues at hand and lead to more effective interventions and policies.

As we continue to grapple with the growing epidemic of vaping and its impact on mental health, it’s clear that a multifaceted approach is needed. By combining rigorous research, targeted interventions, and comprehensive education efforts, we can work towards mitigating the mental health risks associated with e-cigarette use and promoting overall well-being, particularly among vulnerable populations like adolescents and young adults.

3 ways vaping affects mental health

News Article

Topic

• Targeted Communities

Subtopic

• Mental Health

While it is well known that nicotine harms developing brains, including by making young people more susceptible to addiction, lesser known are the worrying connections between nicotine and mental health.

Though nicotine has not been found to directly cause mental health conditions, peer-reviewed studies reveal troubling links between vaping, nicotine, and worsening symptoms of depression and anxiety, as well as higher odds of having a depression diagnosis. Here are three ways vaping affects mental health.

Current e-cigarette users have double the odds of having a diagnosis of depression compared to those who have never vaped

Can vaping cause depression and anxiety?

According to a 2019 JAMA study of nearly 30,000 current e-cigarette users above age 18, frequent vaping is tied to even higher odds – 2. 4X – of having a diagnosis of depression compared to never users.

The study also showed current e-cigarette users had 1.67X higher odds and former e-cigarette users had 1.52X higher odds of reporting at least one day of poor mental health in the past month compared to never users who reported no days of poor mental health. Researchers also believe that trace metals in vape liquid may play a role in the potential link between vaping and depression.

Vaping can worsen symptoms of depression

Does vaping make you depressed?

Based on the results of a 2017 study of nearly 2,500 ninth graders who had never previously used e-cigarettes or combustible tobacco in Los Angeles, those who used e-cigarettes at a higher frequency were associated with higher depressive symptoms. This also included feeling sad or having crying spells – a year later.

Nicotine use is significantly associated with higher levels of conditions like ADHD

Does vaping cause ADHD?

A 2019 study of U. S. college students found that vaping is significantly associated with higher levels of ADHD symptoms, and nicotine dependence was correlated with greater anxiety symptoms.

It is critical to both prevent teens and young adults from vaping or smoking and to help those who are addicted to quit as soon as possible. Not only does quitting break the addiction to nicotine and reduce health-related risks associated with tobacco use, it can also improve mental health. A 2014 meta-analysis showed quitting smoking is linked with lower levels of anxiety, depression and stress as well as improved positive mood and quality of life compared with continuing to smoke. This is Quitting^® is a free and anonymous quit resource from Truth Initiative that has helped more than 350,000 on their journey to quit vaping.

For free help with quitting vaping, text DITCHVAPE to 88709.

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Rising vaping rates among lesbian, gay, and bisexual young people outpace peers, widening tobacco use gap

Depression & anxiety symptoms linked to vaping nicotine and THC in teens and young adults

Research Highlights:

• A study of more than 2,500 people ages 13-24 found that nicotine-only vapers, THC-only vapers and dual vapers (of nicotine and THC) were more likely to report anxiety symptoms, depressive symptoms and suicidal thoughts when compared with their peers who did not use electronic cigarettes or vape THC.
• Approximately 60% of the nicotine-only, THC-only and dual vapers self-reported that they experienced anxiety symptoms, versus about 40% of participants who never vaped. Anxiety symptoms were more frequently reported among THC-only vapers.
• Over half of the nicotine-only, THC-only and dual vapers self-reported that they experienced symptoms of depression versus 25% of non-vapers.

Embargoed until 3 p.m. CT/4 p.m. ET, Tuesday, February 28, 2023

DALLAS, February 28, 2023 — A survey of more than 2,500 teens and young adults led by the American Heart Association found that vaping nicotine and THC, the psychoactive component in marijuana, was associated with self-reported symptoms of depression and anxiety. The study’s preliminary findings will be presented at the Association’s Epidemiology, Prevention, Lifestyle & Cardiometabolic Health Scientific Sessions 2023, which will be held in Boston, February 28-March 3, 2023, and offers the latest science on population-based health and wellness and implications for lifestyle and cardiometabolic health.

The use of pod-based e-cigarettes has surged among youth and young adults in recent years. Previous studies have identified links between vaping and symptoms of both anxiety and depression among young adults.

“Younger people have long been vulnerable to tobacco use, may experience greater harm from nicotine and other drugs and may be targeted by tobacco advertisers and marketers,” said study author Joy Hart, Ph.D., a professor of communication at the University of Louisville in Kentucky. “E-cigarette devices are still relatively new compared to other tobacco products, such as combustible cigarettes and pipes, so more research is needed to try to better understand the popularity of e-cigarettes, including reasons for vaping and the associated health risks among youth.”

The researchers, several of whom work for the Association, conducted an online survey among 2,505 teens and young adults, ages 13-24, to gauge mental health differences among nicotine-only vapers, THC-only vapers, dual vapers of both nicotine and THC and people who had never vaped any product. The study was focused on 1,921 people who had never vaped or were current vapers, defined as having vaped in the past 30 days. Of those participants, 562 individuals reported they had never vaped, 370 had vaped only nicotine, 159 had vaped only THC, and 830 were dual vapers of nicotine and THC.

The analysis of the participants’ survey responses found:

• Approximately 70% of the THC-only vapers and 60% of the nicotine-only vapers and dual vapers reported experiencing anxiety symptoms — such as worries, flashbacks, panic attacks and situational anxieties— within the past week, compared to about 40% of participants who had never vaped.
• Over half of the nicotine-only vapers, THC-only vapers and dual vapers reported experiencing symptoms of depression — such as difficulty engaging in or being interested in activities normally enjoyed, whether they felt that depression interfered with their ability to do the things they needed to do at work, at school or at home and whether depression interfered with their social life and relationships — within the past week, compared to 25% of non-vapers.
• More than 50% of people in all vaping groups reported having suicidal thoughts within the past 12 months, compared to only one-third of the non-users.
• About a quarter of the dual vapers and nicotine-only vapers started vaping nicotine to calm down or feel less stressed, and one-third of participants in both groups reported that they currently vaped nicotine to cope with feelings of anxiety. In contrast, about half of THC-only vapers started vaping THC and currently vaped THC to relieve anxiety symptoms.
• Around 20% of nicotine-only vapers and dual vapers started vaping to help feel less depressed and currently vaped for this reason. About one-third of THC-only vapers started vaping THC and nearly half currently vaped TCH to feel less depressed.

Dual vapers were significantly more likely than nicotine-only vapers to indicate addiction to nicotine, which was defined in this study as behavior such as waking up at night to vape. Dual vapers of nicotine and THC were also significantly more likely to say they felt less depressed after they started vaping, whereas nicotine-only vapers were more likely to report that vaping had no impact on their feelings of depression. This may be related to dual users’ stronger addiction to these products, rather than the positive impacts of the products on their mental health, the researchers said.

“Although we knew that THC was commonly vaped, we were surprised to have so many dual vapers—more than double the nicotine-only vapers. Dual use may either compound the addictive nature of vaping or attract people who are more prone to addiction, as well as have an impact on symptoms of depression. These findings suggest the importance of addressing the use of THC and the need for building resilience and coping skills for teens and young adults,” Hart said.

The study had limitations: the use of cross-sectional data did not allow researchers to assess whether symptoms of anxiety and depression, as well as suicidal thoughts, were caused or exacerbated by the use of the THC and nicotine vapes, or whether the existence of those symptoms had an effect on the use of the vape products; collecting online data via a web-based panel meant that participants may not be representative of all U. S. teens and young adults; and the data were self-reported.

“When better coping skills are developed, there may be fewer temptations to try to manage anxiety symptoms and similar mental health challenges through vaping, as well as better refusal skills if offered an electronic cigarette. Increased priority on more positive behaviors to alleviate tension and manage anxiety symptoms may reduce the likelihood of vaping, possible addiction and the increased risk of negative health outcomes,” said Rose Marie Robertson, M.D., FAHA. Robertson is deputy chief science and medical officer of the American Heart Association, co-director of the Association’s National Institutes of Health/U.S. Food and Drug Administration-funded Tobacco Center of Regulatory Science and senior author on the study. “There is also an urgent need for effective communication campaigns and educational programs to increase understanding among youth and young adults of the risks of using e-cigarettes.”

Future research, Robertson said, is needed to examine the long-term connections between mental health and vaping, whether nicotine-only, THC-only or both nicotine and THC.

“This study showed the striking significance of issues with mental health in users of both nicotine vapes as well as THC vapes, and as new products continue to come on the market, I think that this is something that we will continue to see,” said Loren E. Wold, Ph.D., FAHA. Wold is assistant dean for biological health research in the College of Nursing, a professor in the Colleges of Nursing and Medicine (physiology and cell biology) at The Ohio State University and lead of the writing committee for the Association’s 2022 Statement on Cardiopulmonary Consequences of Vaping in Adolescents. “These products were developed as smoking cessation tools for those that use traditional cigarettes, so I’m very curious now what the implications are with mental health in users who are using these products to help stop smoking.”

Additional co-authors are Jeffrey Willett, Ph.D.; Allison Groom, M.A.; Robyn L. Landry; Angel Bassett, M.A.; Mary Dunn, Ph.D.; Kandi Walker, Ph.D.; Thomas Payne, Ph. D.; and Anshula Kesh, M.P.H., B.D.S. Authors’ disclosures are listed in the abstract.

The study was funded by a grant from the Kaiser Permanente National Community Benefit Fund at the East Bay Community Foundation. Through the American Heart Association Tobacco Center for Regulatory Science, the Association works closely with investigators at institutions across the country to pursue research that adds to the existing knowledge about the health impacts of smoking and nicotine-related products including e-cigarettes, findings that can help inform public health and the regulation of tobacco products.

Statements and conclusions of studies that are presented at the American Heart Association’s scientific meetings are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. Abstracts presented at the Association’s scientific meetings are not peer-reviewed, rather, they are curated by independent review panels and are considered based on the potential to add to the diversity of scientific issues and views discussed at the meeting. The findings are considered preliminary until published as a full manuscript in a peer-reviewed scientific journal.

The Association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific Association programs and events. The Association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and biotech companies, device manufacturers and health insurance providers and the Association’s overall financial information are available here.

Additional Resources:

• Multimedia is available on the right column of release link https://newsroom.heart.org/news/depression-anxiety-symptoms-linked-to-vaping-nicotine-and-thc-in-teens-and-young-adults?preview=c30b14f8eb24c1a3519f6e7e9e0d0513
  
  • Video interview: Rose Marie Robertson, M.D., FAHA, senior author on the study and deputy chief science and medical officer of the American Heart Association and co-director of the Association’s National Institutes of Health/U. S. Food and Drug Administration-funded Tobacco Center of Regulatory Science.
  • Video interview: American Heart Association volunteer expert, Loren E. Wold, Ph.D., FAHA, assistant dean for biological health research in the College of Nursing, a professor in the Colleges of Nursing and Medicine (physiology and cell biology) at The Ohio State University and lead of the writing committee for the Association’s 2022 Statement on Cardiopulmonary Consequences of Vaping in Adolescents.

• AHA news release: Use of e-cigarettes had negative cardiovascular effects similar to smoking cigarettes (October 2022)
• AHA news release: People who vape had worrisome changes in cardiovascular function, even as young adults (October 2022)
• AHA news release: No health benefits among adults who used both e-cigarettes and traditional cigarettes (May 2022)
• AHA health information: Quit Vaping – Quit Smoking – Quit Tobacco
• AHA health information: The Ugly Truth About Vaping
• For more news from AHA EPI Lifestyle Conference 2023, follow us on Twitter @HeartNews #EPILifestyle23.

The American Heart Association’s EPI/LIFESTYLE 2023 Scientific Sessions is the world’s premier meeting dedicated to the latest advances in population-based science. The meeting will be held Tuesday-Friday, February 28 – March 3, 2023, at the Omni Boston Seaport in Boston, Massachusetts. The primary goal of the meeting is to promote the development and application of translational and population science to prevent heart disease and stroke and foster cardiovascular health. The sessions focus on risk factors, obesity, nutrition, physical activity, genetics, metabolism, biomarkers, subclinical disease, clinical disease, healthy populations, global health and prevention-oriented clinical trials. The Councils on Epidemiology and Prevention and Lifestyle and Cardiometabolic Health (Lifestyle) jointly planned the EPI/Lifestyle 2023 Scientific Sessions. Follow the conference on Twitter at #EPILifestyle23.

About the American Heart Association

The American Heart Association is a relentless force for a world of longer, healthier lives. We are dedicated to ensuring equitable health in all communities. Through collaboration with numerous organizations, and powered by millions of volunteers, we fund innovative research, advocate for the public’s health and share lifesaving resources. The Dallas-based organization has been a leading source of health information for nearly a century. Connect with us on heart.org, Facebook, Twitter or by calling 1-800-AHA-USA1.

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For Media Inquiries and AHA Expert Perspective:

AHA Communications & Media Relations in Dallas: 214-706-1173; [email protected]

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Scientists have found out how smoking and depression are connected

Smoking can lead to depression, Israeli scientists say. Smokers are much more likely to experience depressive symptoms, and quitting the habit improves mental health.

Smoking is not only harmful to physical health, but is also associated with mental disorders, researchers from the Hebrew University in Jerusalem found out. The study was published in the journal PLOS ONE .

Smoking, including passive smoking, is one of the main risk factors for morbidity and mortality worldwide, the authors note. Almost 90% of smokers acquire this habit before adulthood, 98% before the age of 26.

Previous studies have shown that people with depression and other mental disorders are more likely to start smoking than mentally healthy people. In particular, many studies have noted that smokers have a much lower quality of life and more pronounced symptoms of anxiety and depression.

More recent data have shown that there may be an inverse relationship – smoking becomes a predisposing factor for mental problems, and quitting it is associated with a decrease in depressive symptoms.

Together with colleagues from Serbia, the authors of the work interviewed more than 2,000 students of Serbian universities.

As it turned out, smoking students were several times more likely to suffer from depression than their non-smoking peers.

In particular, at the University of Pristina, depression was observed in 14% of smoking students and only in 4% of non-smokers, and in the University of Belgrade – in 19% smokers and 11% non-smokers. Women were more likely to suffer from depressive symptoms.

In addition, regardless of economic or social status, students who smoke were also more likely to complain of depression and had lower mental health scores (energy, social functioning) than non-smokers.

“Our study confirms existing evidence that smoking and depression are closely linked,” says Prof. Hagai Levin. “It’s too early to say that smoking causes depression. But tobacco seems to have a negative effect on our mental health.”

The Israeli government is actively cracking down on smoking – as of 2020, cigarettes are banned from display in stores, warning labels on packs are increased to 65% of the pack size, and all tobacco products and e-cigarettes must be sold in the same packaging, without logos or display manufacturer’s brand.

Levin would like such measures to take into account the impact of smoking on mental health.

“I encourage universities to advocate for the health of their students by creating cigarette-free campuses where not only is smoking banned, but tobacco advertising is also banned,” he says. “Combined with policies to prevent, screen and treat mental illness, these steps will go a long way towards combating the harmful effects of smoking on our physical and mental health.”

Researchers suggest that the whole thing is the effect of nicotine on the activity of neurotransmitters.

In addition, other chemicals in cigarette smoke indirectly stimulate the release of dopamine associated with feelings of satisfaction, which ultimately leads to mood swings.

Students generally have more mental health problems than non-degree peers, researchers note. This is probably due to the stress caused by the strict academic requirements. The authors of the work suggest that depression can push them to smoke, and then, in turn, only aggravate their condition. The researchers hope that quitting smoking will allow students to improve their mental health, but this remains to be tested.

Previously, British geneticists drew attention to the fact that

smoking can provoke not only depression, but also schizophrenia.

Since the prevalence of smoking among people with depression and schizophrenia is generally higher than among the rest of the population, they decided to find out whether the diseases predispose a person to smoking or vice versa.

After analyzing the genomes of almost half a million Britons and comparing them with data on their diseases and lifestyle, they found that a genetic predisposition to depression is associated with an increased likelihood that a person will start smoking. However, no such association was found for schizophrenia. At the same time, smokers, even without a genetic predisposition, were more prone to depression and schizophrenia.

Smoking contributed to the development of schizophrenia and depression

British geneticists have found a causal relationship between smoking and the risk of schizophrenia and depression. Using a genome-wide association analysis, they showed that smokers were 2.27 times more likely to develop schizophrenia and 1.99 times more likely to develop depression. At the same time, feedback was also observed – but only for depression. An article describing the study was published in Psychological Medicine .

There are more smokers among people with mental disorders than among the healthy population. Due to the additional health problems that smoking causes (such as lung disease and cardiovascular disease), their life expectancy can be significantly reduced, so the nature of the relationship between smoking and mental disorders needs to be understood accurately. However, it is not always obvious and it is not possible to establish it exactly even with the help of studying biochemical mechanisms.

It is known, for example, that substances contained in tobacco inhibit the production of monoamine oxidase, an enzyme that breaks down monoamine neurotransmitters, such as dopamine. Antidepressants from the group of monoamine oxidase inhibitors have a related effect, from which it can be concluded that smoking could be used as a means of self-treatment in depression.

On the other hand, dopamine itself at high concentrations of nicotine in the body begins to be produced more strongly. Increased activity of dopaminergic neurons, in turn, is one of the obvious biomarkers of schizophrenia: this is why most of the drugs that stop the symptoms of the disease – antipsychotics – act specifically on dopamine. To show the connection between smoking and the development of mental disorders through the influence on the work of brain neurotransmitters, therefore, it is possible, but it will remain two-sided; in addition, smoking may well be a side variable.

Robin Wotton of the University of Bristol and colleagues tried to find a causal relationship between smoking and the risk of developing mental disorders using a genome-wide association search. To do this, they used the results of a recent study on genetic markers associated with smoking as a binary variable, which found 378 single nucleotide polymorphisms in a sample of more than 1. 3 million people.

After that they did their own research on the genomes of 462690 people who provided information on how much they smoke, how often, and their attempts to quit. In the end, the scientists were able to find 126 polymorphisms related to the duration of smoking, the number of cigarettes smoked, and whether people tried to stop (and also whether they succeeded).

Next, scientists used already known single nucleotide polymorphisms associated with the development of depression and schizophrenia (40 and 114, respectively). Scientists conducted a statistical analysis of the relationship between smoking and the development of mental disorders using Mendelian randomization methods – they evaluate the influence of genetic markers on the development of any trait as instrumental variables and help determine a causal relationship (with an eye to the fact that genetic factors are a variable random).

The analysis showed that smoking (both a binary variable and all studied indicators) is a risk factor for the development of both schizophrenia and depression (both p < 0.