SUMMARY: In this post, I argue that the current anxiety epidemic could be due to a new strain of virus in circulation that affects the brain, leading to mental symptoms.
The prevalence of generalised anxiety disorder (GAD) has rocketed in recent decades, with multiple studies showing that GAD has doubled in younger populations between 2008 and 2018.1 2 3 4
The popular view is that this epidemic of GAD results from modern lifestyle factors such as social media usage, reading too much bad news (doomscrolling), not being able to switch off due to the ubiquity of electronic communications, peer pressures, economic difficulties, and so forth.
No doubt modern lifestyle factors may have undesirable effects, and may create temporary anxiety. And it may well be a good idea to ban social media for young children. But many people confuse regular temporary anxiety with GAD, and they are not the same thing.
GAD is a psychiatric disease rooted in measurable brain abnormalities and brain dysfunctions. It is not the same as the normal healthy anxiety that arises from everyday stressful events. Normal anxiety dissipates when the stressor causing it goes away, whereas the anxiety of GAD remains ever-present, as it is not driven by external stressors, but appears to be caused internally by brain dysfunction.
Even when there are no external stressors, a person with GAD will still experience anxiety, because the anxiety likely arises from a dysfunction in the brain's anxiety circuits: it is as if the anxiety circuits have got stuck in the "on" state, and are thus constantly generating anxiety. Although of course external stressors can exacerbate the anxiety of GAD even further.
What's more, in the medical literature, there is no evidence that everyday stressful events can trigger the psychiatric illness of GAD. I spent some time searching PubMed, but could find no studies that show regular life stresses can lead to GAD.
The only relevant study I did find was this one, which found that severe stressors (like bereavement or a personal financial crisis) may potentially contribute to GAD development. But severe stressors are a different category to everyday stressors, as we know the former can also trigger PTSD.
So the idea that the current generalised anxiety disorder epidemic might arise due to social media and the like seems somewhat tenuous, even though it is a popular notion. Certainly children's social media use might create temporary anxiety, but temporary anxiety is not GAD. And it is GAD diagnoses which have increased.
Thus this suggests there could be some other factors causing the current GAD epidemic — such as biological factors
So I want to examine the possibility that one or more emerging new strains of virus which are more neurotropic or neuroinflammatory might underpin the GAD epidemic. Or the possibility that higher viral loads in the general population might be driving the GAD epidemic.
It is possible that new strains of virus may now be circulating around the globe, strains which may have more pernicious effects on the brain, either by infecting the brain directly and causing persistent neuroinflammation, or by chronically infecting the gut, and ramping up neuroinflammation indirectly, via the well-known gut-to-brain connections, such as the vagus nerve.
Our bodies may also now harbour a higher number of viruses and other microbes as a result of the increased urbanisation and globalisation we have witnessed in recent decades. This is because greater population density allows viruses and other micro-organisms to transmit person-to-person more easily; and factors such as increased air travel and increased human movement around the world allow viruses from one region to spread globally.
Many psychiatric conditions have been linked to chronic low-level neuroinflammation.1 2 So if you have one or more persistent viruses or other micro-organisms in your body or brain, which the immune system is constantly fighting to keep under control, thus generating chronic inflammation, this may lead to mental symptoms. And indeed, several microbes have been found associated with anxiety symptoms:
Toxoplasma gondii is linked to anxiety; this is a parasite that infects the brain and can be caught from eating undercooked meat or from contact with cat faeces.1 2 3 4
The bacterium Helicobacter pylori has also been linked to anxiety,1 2 as have cytomegalovirus1 2 and Epstein-Barr virus;1 all three of these microbes are normally caught from other people through person-to-person contact (or more rapidly through intimate kissing).
These are the microbes that science knows are linked to anxiety, but there are likely others which may also be associated, and here I am hypothesising that there may be new strains of virus in circulation that can induce GAD in some people.
Many psychiatrists who have examined the current anxiety epidemic, and the examined general epidemic of increased mental health symptoms in young people (like anxiety, panic attacks, eating disorders, etc) have focused on factors such as social media being the possible cause. As far as I am aware, none have considered the possibility of an infectious aetiology. This is unfortunate, because mental ill health involves a lot of torment, and nobody wants to see very young children suffer in this way, yet a possible infectious microbial cause of the GAD epidemic is not even on the radar.
Some further reading on the microbial connection to psychiatric illnesses:
- 2004, Virus-induced neurobehavioral disorders: mechanisms and implications - Keizo Tomonaga
- 2008, Infected with Insanity: Could Microbes Cause Mental Illness? - Scientific American
- 2008, Role of Chronic Bacterial and Viral Infections in Neurodegenerative, Neurobehavioral, Psychiatric, Autoimmune and Fatiguing Illnesses: Part 1 - Garth L. Nicolson et al
- 2010, Role of Chronic Bacterial and Viral Infections in Neurodegenerative, Neurobehavioural, Psychiatric, Autoimmune and Fatiguing Illnesses: Part 2 - Garth L. Nicolson et al
- 2012, Anxiety and Depression: Linkages with Viral Diseases - Steven S Coughlin
- 2012, Can an Infection Suddenly Cause OCD? - Harvard Health Blog
- 2013, People Hospitalized For Infections Are 62% More Likely To Develop A Mood Disorder - Medical Daily
- 2019, Psychiatric Disorders: Are Infectious Agents to Blame? - Psychiatric Times
- 2023, Microbes and Mental Illness: Past, Present, and Future - Robert C Bransfield et al
- 2024, Viral infections in etiology of mental disorders: a broad analysis of cytokine profile similarities – a narrative review - Piotr Lorkiewicz et al