7 Hidden Reasons Why Depression Is Skyrocketing


Depression appears to be spreading like cancer. That’s according to a recent Gallup poll that surveyed more than 5,000 U.S. adults about their depression diagnoses. The poll found that reports of clinical depression have reached a new high, with 29% of respondents having been diagnosed and 17.8% having been treated for it. That’s a hefty 10% and 7% increase, respectively, since these numbers were reported in 2015.

What’s behind this significant increase? On the positive side, Americans now have more awareness about depression. That usually leads to more people seeking help than in years past. It also means that more medical professionals are taking it seriously and screening for it.

On a less optimistic note, however, there are several potential culprits that may have created this uptick in depression. Some, such as COVID-19, were not present in previous years. Let’s look at 7 hidden causes that may be contributing to depressive symptoms, and how they affect the brain and mental health.

Depression often co-occurs alongside other mental health concerns, like anxiety, PTSD, substance use disorder, and more. Untreated, it can wreak havoc on all areas of a person’s life, from work and school to family and physical health. Click To Tweet


1. Inflammation

Inflammation is a silent cause of depression. That’s because inflammation is an internal symptom, one we can’t necessarily see. But we can think of it as a fire that’s burning at a low level behind the scenes. This common health problem affects everything in the body, including the brain, which then can create depressive symptoms.

Experts have studied and established the link between inflammation and mood disorders. Research has found that cytokines (pro-inflammatory molecules) can affect levels of the mood stabilizer hormone serotonin, for example.

This study hypothesized that other reasons for this inflammation-depression link may include “dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, pathologic microglial cell activation, impaired neuroplasticity, and structural and functional brain changes.” More research is needed to find out further details about the connection between inflammation and depression, but we know it exists.

2. COVID-19

It will take years to determine just how deeply COVID-19 impacted our world. But the Gallup poll noted that depression stats have climbed higher than ever after the pandemic. Reasons for this, the report explained, may be due to many factors.

For example, social interruptions have led to increased isolation and loneliness. Then there are the additional psychological burdens, such as fear of catching COVID, or the exhaustion experienced among healthcare workers. Finally, there have been factors like increased substance abuse and pandemic-related disruptions in mental health care and other services.

Physical changes are a factor, too, among those who have had COVID—especially those who experience symptoms of long COVID. The virus creates inflammation, which (as noted above) is associated with signs of depression.

Brain SPECT imaging scans at Amen Clinics show that changes in the brain take place after COVID. For example, some post-COVID scans reveal increased activity in the emotional centers of the brain. Overactivity in this area of the brain is often associated with depression.

3. Hypothyroidism

This condition, which is far more common in women, occurs when the thyroid gland does not make enough of the thyroid hormone. This may cause memory loss, fatigue, weight gain, and, yes, depression. On SPECT scans, hypothyroidism is associated with overall decreased blood flow in the brain. This is often linked to cognitive impairments as well as mental health issues like depression.

Unfortunately, too many people living with thyroid issues are not receiving the medical attention and treatments they need. Though the American Thyroid Association estimates 20 million Americans have some form of thyroid disease, as many as 60% of those with the condition are unaware of it.

If you experience the onset of depression and can find no other obvious cause, it is wise to get your thyroid levels checked out by a medical professional.

4. Head trauma

Traumatic brain injuries are strongly associated with major depressive disorder. One review that analyzed dozens of studies noted that it’s the most common psychiatric disorder to appear after these injuries.

According to these studies, the likelihood of developing depression within the first year after sustaining a head injury is between 33% and 52%. Surprisingly, an increased risk of depression is found not only in those with severe head trauma but also in mild cases. This leads to an increased risk of more serious post-injury effects, including suicide.

Researchers suggest depression may be related to damage to brain tissue as a result of a head injury. Certain people, such as those with a previous depression history or those with outside adverse factors like unemployment, may be more at risk.

5. Exposure to toxins

Toxins in our environment can poison the brain and lead to mental health conditions like depression. Toxins destroy the body in many ways. Like many of the concerns listed here, they reduce blood flow to the brain, which is associated with depression.

They also interfere with hormone production, disrupt the immune system and the gut’s microbiome, and contribute to obesity. DNA damage via toxin exposure also ages the brain and can impact both mood and memory. Any of these issues can be associated with depressive symptoms.

6. Heart disease

Research shows there’s a strong connection between heart disease and depression. People who have experienced a heart attack, stroke, or heart failure are at increased risk for mood disorder. Approximately 20%-30% of cardiac patients experience depression, according to research. This means cardiac patients are 2-3 times more likely to develop depression compared with the general population.

Experts suggest that cardiac events can trigger depressive symptoms for a variety of reasons. These include pain as well as fears about dying, disability, or financial troubles. Impaired blood flow, commonly seen in heart disease, can also play a role in mental health conditions. SPECT imaging shows that decreased blood flow negatively impacts the brain and mental well-being.

7. Certain medications

Some prescription drugs have been linked to depressive symptoms, such as sadness, hopelessness, and negativity. Medications associated with an increased risk of depression include oral contraceptives, corticosteroids, isotretinoin (acne medication), interferon-alpha (an anti-viral drug), high blood pressure drugs, and statins.

A 2023 study using data from 264,557 women found that an alarming number of those who use oral contraceptives develop depression. Women who were teenagers when they started taking the pill had a 130% higher rate of depressive symptoms. For those who began taking the pill as an adult, there was a 92% increase in mood disorder.


Even though depression is more widespread than ever, there is a silver lining. As more awareness of this mental health condition grows, more people can get the diagnosis and help they need. Those who have not been diagnosed or treated, however, may not know whether they need help.

Here are some symptoms and signs of depression to watch out for:

  • Persistent sadness or negativity
  • Hopelessness
  • Restlessness
  • Irritability
  • Changes in sleep patterns (oversleeping or too little sleep)
  • Changes in appetite (weight loss or gain)
  • Lower energy levels
  • Difficulty concentrating or memory loss
  • Loss of interest in pleasurable activities
  • Suicidal thoughts or attempts

These symptoms are only a fraction of the ways in which depression can hamper our functioning. Also keep in mind that there are 7 types of depression, each with its own manifestations and effects on the brain and body.

Finally, depression often co-occurs alongside other mental health concerns. For example, depression and anxiety co-exist 75% of the time. PTSD and substance use disorder also commonly occur with mood disorders, such as depression or bipolar disorder.

It’s crucial to seek medical help to diagnose this serious disorder. Untreated, it can wreak havoc on all areas of a person’s life, from work and school to family and physical health.

Most importantly, it’s critical to remember that depression is a symptom. You need to find out what’s causing it to treat it effectively. Be sure to find a mental health professional who looks at all the biological, psychological, social, and spiritual issues that may be contributing to depressive symptoms.

A comprehensive evaluation that includes lab work, brain SPECT imaging, psychological testing, and more can be invaluable. This can help determine the type of depression at work and its causes, which allows for more targeted treatments for depression. This is an especially helpful step when depression is associated with one of these hidden reasons, which are too often overlooked.

Depression and other mental health issues can’t wait. At Amen Clinics, we’re here for you. We offer in-clinic brain scanning and appointments, as well as mental telehealth, clinical evaluations, and therapy for adults, teens, children, and couples. Find out more by speaking to a specialist today at 888-288-9834 or visit our contact page here.


  1. My wife has depression and anxiety. Just a short time ago we were considering a trip to Atlant from south Florida. The cost was around$3,000. I recently found your office in nearby Ft Lauderdale but now the cost is over $5,000. We are seniors on a fixed income . Who can afford this?

    Comment by Walter Kalinoski — September 25, 2023 @ 5:05 AM

  2. I appreciate the recognition of thyroid disorders as a contributor to depression! My experience after referral of hundreds of clients to their PCP for thyroid testing is that American Medicine is woefully inadequate. Some physicians outright refuse to test. Some test TSH only, which does not identify the auto-immune form of thyroid disease. The auto-immune form of thyroid disease is the most common cause of low thyroid in the US so anti-body testing is a must. Furthermore, modern medicine does not even agree on what constitutes a "normal" TSH – some say 3, some say 5, some say 10. That's a pretty big spread. It is such a disservice to test TSH only and tell patients that their thyroid is "Normal". One can only say that factually if the auto-immune form of thyroid disease has been adequately ruled out. If physicians refuse to test, I refer clients to Direct Labs, Quest Labs, etc. where they can do the testing themselves and then take results to their physicians. I'm glad Dr. Amen is increasing awareness about the connection between thyroid and depression. I think it may not be enough to say "get your thyroid tested" until medicine does it adequately.

    Comment by Louise — September 25, 2023 @ 8:03 AM

  3. Don't forget the effect of turning the clocks back one hour in November!!!!!!!!!!

    Comment by Holly Matisis — September 25, 2023 @ 9:17 AM

  4. I had Major Depression most of my life. Then at age 74 I joined the Bredesen protocol and started taking binders for mold & mycotoxins in my body. The MDD is now in complete remission. That was 4 years ago.

    Comment by Lois Dorn — September 25, 2023 @ 10:20 AM

  5. whoah this blog is excellent i love reading your posts. Keep up the great work! You know, a lot of people are looking around for this information, you can help them greatly.

    Comment by gralion torile — November 26, 2023 @ 2:55 PM

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