A recently published study identifies a specific type of brain cell that may help researchers improve treatment for anxiety and obsessive-compulsive disorder. Obsessive-compulsive disorder, most often called OCD, is a type of anxiety disorder that can significantly decrease overall quality of life and wellbeing.
Almost everyone on earth understands anxiety.
With very few exceptions, we all worry about something.
Working adults worry about adulting: money, retirement, healthcare, and everything associated with living in the modern world.
Parents worry about their kids.
And yes, even kids worry. They worry about their parents and they worry about the future. But most of the time, they worry about kid things: friends, their hobbies, and whether or not they’re going to get in trouble for eating the last cookie.
Those types of worries are common and typical. However, when worry or anxiety crosses a threshold and begins to impair daily life, it becomes a clinical mental health disorder. Here’s a general definition of clinical anxiety from the American Psychological Association (APA):
“Anxiety is an emotion characterized by feelings of tension, worried thoughts, and physical changes like increased blood pressure. People with anxiety disorders usually have recurring intrusive thoughts or concerns. They may avoid certain situations out of worry. They may also have physical symptoms such as sweating, trembling, dizziness, or a rapid heartbeat.”
Those intrusive thoughts and avoidance behaviors are particularly pronounced for people with obsessive-compulsive disorder (OCD). To learn more about anxiety disorders and obsessive-compulsive disorder, please read our pages here:
Anxiety Treatment
Obsessive-Compulsive Disorder Treatment
In this article, we’ll share information from a new study that sheds light on the brain mechanisms behind OCD. First, though, we’ll offer an overview on anxiety disorders and obsessive-compulsive disorder. We’ll review the important facts and figures about anxiety and OCD and discuss the impact of COVID-19 on anxiety and OCD. Then we’ll describe the results of this new research, and explain how it may benefit people with ODC in the near future.
Anxiety Disorders and Obsessive-Compulsive Disorder: Essential Facts
First, let’s look at the latest information on the prevalence of anxiety. Here’s the most recent data from the World Health Organization (WHO):
- 1% of people in the world report anxiety
- Rates are similar across age groups
- Rates are over 50% higher among women
And here’s the latest information for the U.S.:
- Age 18+: 31.1% report any anxiety diagnosis
- Past year diagnosis: 19.1%
- With major impairment: 22.8%
- Age 12-17: 31.9%
- With major impairment: 8.3%
Those are the big-picture figures from before COVID-19. It’s clear that a worldwide health crisis has the potential to increase anxiety in everyone, whether they have an anxiety disorder or not. Long range data showed that anxiety did increase significantly across most demographics during the beginning of the pandemic but returned to pre-pandemic levels – or close – by mid-2022.
The meta-analysis “Anxiety Linked to COVID-19: A Systematic Review Comparing Anxiety Rates in Different Populations” showed those pandemic-related changes. Researchers examined results from 87 studies with data on over 750,000 people. They identified increases in the prevalence of anxiety among specific demographic groups, including:
- Healthcare workers: 36%
- University students: 34.7%
- General population: 34%
- Teachers: 27.2%
- Parents: 23.3%
- Pregnant women: 19.5%
- Police: 8.79%
Factors associated with increases in anxiety symptoms:
- Female gender
- Younger age
- Pre-existing mental conditions
- Lower socioeconomic status
- High levels of exposure to infection, e.g. essential workers
The Consequences of Untreated Anxiety
In most cases, untreated anxiety gets worse over time, rather than better. Without treatment, the symptoms of anxiety can have a profound, negative, disruptive impact on daily life. Problems associated with untreated anxiety include:
- Difficulty establishing and keeping health relationships
- Decreased ability to meet basic work or academic expectations
- Problems finding and maintaining employment
- Problems becoming financially self-sufficient
- Gradual increase in alcohol or substance use
- Exacerbation of co-occurring mental health disorders
- Withdrawal from friends and family/self-isolation
- Suicidal ideation/thoughts of self-harm
Those are the most important things to understand about anxiety, anxiety disorders, and the impact of the COVID-19 pandemic on people with anxiety in the U.S. Millions of people in the U.S. face the challenge of clinical anxiety every year, and the pandemic did not help them. For people with anxiety, the pandemic elevated risk of increased symptoms and elevated the risk of experiencing the long-term negative consequences of anxiety.
That’s why reporting on this research is critical: as the need for treatment increases, the need for new and innovative treatments increases, as well.
Next, we’ll share the same information about OCD: basic prevalence rates, the impact of COVID-19, and the consequences of untreated OCD.
Obsessive-Compulsive Disorder: Essential Facts
The article “A Meta-Analytic Review of OCD Prevalence Worldwide” examined 34 peer-reviewed journal articles published as of 2017. Here’s what they report:
- Current OCD diagnosis: 1.1% of adults worldwide
- Females: 1.5%
- Males: 1.0%
- Past-year OCD diagnosis: 0.8%
- Lifetime OCD diagnosis: 1.3%
Now let’s look at rates of OCD in the U.S., as reported by the National Institute of Mental Health (NIMH) Here’s their most recent data:
OCD Among Adults 18+ in the U.S.
- Clinical diagnosis of OCD: 1.2%
- Females: 1.8%
- Males: 0.5%
- Severity of OCD:
- Serious impairment: 50.6%
- Moderate impairment: 34.8%
- Mild impairment: 14.6%
It’s clear to almost anyone familiar with OCD that a public health emergency like the COVID-19 pandemic had the potential to exacerbate the symptoms of OCD. The data tell an interesting story: some showed drastic increases, while other showed none at all. Many experts cite the fact that people diagnosed with OCD might have developed tools during treatment that mitigated the overall impact of OCD. However, there’s no data to support that assertion – but it is logical.
Keep that thought in mind while reviewing the following data on the impact of COVID-19 on people with OCD.
In the study “Obsessive-Compulsive Symptoms and the Covid-19 Pandemic: A Rapid Scoping Review,” researchers collected data from 32 peer-reviewed journal articles that examined the impact of COVID-19 on rates of obsessive-compulsive disorder (OCD) and OCD symptoms. Here’s what they found:
- Symptom increase in an average range of 20.0% – 65.3% of people with OCD:
- Some studies showed no change
- One study showed symptom increase in 4% of people with OCD
- Another showed symptom increase in 92% of people with OCD
- Most common symptom increases:
- Handwashing
- Contamination/contamination avoidance behaviors
Factors associated with increases in OCD symptoms.
- Severity pre-pandemic
- Presence of checking/washing symptoms
- Inadequate social support
The Consequences of Untreated Obsessive-Compulsive Disorder
Like untreated anxiety, untreated OCD often gets worse over time, and rarely improved on its own. In the absence of professional treatment and support, the symptoms of OCD can significantly disrupt – and in some cases, completely prevent – an individual from participating in the typical activities of daily life. The negative consequences of untreated obsessive-compulsive disorder include:
- Self-isolation/withdrawing/reducing contact with friends and family
- Problems forming and keeping interpersonal relationships
- Problems meeting basic expectation at work or school
- Difficulty seeking and securing employment
- Difficulty becoming self-sufficient
- Gradual increase of alcohol and/or substance use
- Exacerbation of existing co-occurring mental health disorders
- Development of additional mental health disorders
- Suicidal ideation and/or non-suicidal self-injury (NSSI)/self harm
This information – like the information we share above on anxiety disorders – tells us that a significant number of people in the U.S. and worldwide have clinical OCD. And like anxiety, the pandemic elevated risk of people with OCD experiencing an increase in both negative symptoms and experiencing the negative consequences of untreated OCD.
We’re now ready to look at the study we introduce in the beginning of this article, which shows promising new information on the underlying mechanisms of OCD.
Do Specific Brain Cells Act as an On/Off Switch for OCD-Related Behaviors?
This study, performed on the rodent model in a laboratory setting, examined the impact of the impact of a mutation on a specific gene – called Hoxb8 – that caused laboratory mice to show symptoms of anxiety and engage in obsessive behaviors.
It’s not unusual to identify a gene associated with behavior. That’s one of the primary goals of genetic research in the field of behavioral science. However, in this case, the gene the researchers identified codes for a type of immune cell called microglia not previously associated with anxiety or any atypical type of behavior.
Until now, scientists understood microglia as the immune workhorses of the brain. Like the immune cells that circulate through our bodies called macrophages, microglia – which make up about 10 percent of brain cells – have the ability to patrol the brain, consume, and subsequently expel foreign bodies or harmful pathogens.
This research reveals a new function microglia perform: a specific population of these cells can increase or decrease behaviors associated with anxiety and obsessive-compulsive disorder. Interviewed in the online journal Science Daily, study author Dr. Naveen Nagajaran observes:
“This work is unique and has challenged the current dogma about the role of microglia function in the brain.”
In previous studies, researchers noticed mutations in the Hoxb8 gene caused mice to groom themselves with unusual frequency and duration. This behavior is a symptom of chronic anxiety. In order to explore this phenomenon, the research team designed an experiment that used focused laser light to stimulate or stop the function of microglia generated by the Hoxb8 gene. With the genes either turned on or off, they performed a series of tests on the mice, which measured:
- Grooming behavior
- Maze completion
- Freezing behavior, i.e. stopping all activity and remaining still out of fear
These metrics measure the presence or absence of anxiety and OCD-type behaviors. Excess grooming is a sign of anxiety and OCD-associated behavior, increased time to maze completion indicates elevated anxiety, and increased instances of freezing behavior are associated with both anxiety and OCD.
Lets’ take a look at what they found.
Microglia, Anxiety, and OCD: The Results
It’s rare that results in experiments are so clear.
Here’s what happened:
- When researchers stimulated microglia in one part of the brain, they activated anxiety-related behaviors “like turning on a switch.”
- This confirmed the association of microglia with anxiety
- When researchers stimulated microglia in another part of the brain, they activated grooming behaviors, again, “like turning on a switch.”
- This confirmed the association of microglia with OCD
- When researchers stimulated microglia in a third location, mice showed increased anxiety, increased grooming, and increased freezing behavior.
- This confirmed the association of microglia with anxiety and OCD in different areas of the brain
- When researchers stimulated – i.e. turned on – microglia associated with anxiety, the mice took longer to complete mazes.
- When researchers deactivated -microglia associated with anxiety, the mice completed mazes at typical times and rates.
Researchers also discovered something else.
When they activated non-Hoxb8 microglia and Hoxb8 microglia at the same time, the mice did not show any anxiety or OCD-related behaviors. According to researchers, this indicates that “the two populations of microglia act like a brake and an accelerator.”
That’s a significant finding. Here’s how Dr. Nagajaran describes the results:
“[This] was a big surprise for us. It is conventionally thought that only neurons can generate behaviors. The current findings shed light on a second way that the brain generates behaviors using microglia.”
The team observed that stimulating microglia increased activity in adjacent neurons, which may explain the behavioral changes. Dr. Mario Capecchi, a Noble prize winner and lead researcher on the study, indicated that while these results offered intriguing new answers to some questions, they raised others:
“We want to learn more about the two-way communications between neurons and microglia. We want to know what’s responsible for that.”
How This Research Helps Anxiety and OCD Treatment
In a nutshell, this research opens the door to the potential to turn on or turn off behaviors associated with anxiety and OCD like turning on or off a light switch. The researchers used lasers and other laboratory techniques to activate and deactivate these specific genes and cells, which would be impossible in humans.
However, future research may lead to medications that can regulate – i.e. turn on or off – the Hoxb8 and other genes. In addition, researchers may apply recent techniques in brain stimulation, such as transcranial magnetic stimulation, to stimulate these brain areas. That’s speculation on our part, but the results of this experiment – increasing or decreasing anxiety/OCD behavior by stimulating specific brain cells – indicate that another method of stimulation may yield similar results.
Does anyone believe that in the near future, we may be able to turn on and off anxiety and OCD-related behaviors like an on/off switch?
That seems too good to be true – but this research says it may be possible. For millions of people who experience the severe and disruptive symptoms of anxiety and obsessive-compulsive disorder, this would be a life-changing development.
We’ll keep an eye on the research and report any new results here as soon as they’re published.
Gianna Melendez
Jodie Dahl, CpHT