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The global prevalence of depression and anxiety continues to increase. Sergey Filimonov/Stocksy
  • About 5% of the world’s adult population has depression, and about 40-50% of those with major depression will also experience anxiety.
  • Previous studies have linked depression and anxiety to an increased risk for certain diseases, including cancer.
  • Researchers from the University Medical Center Groningen have discovered evidence to challenge the theory that depression and anxiety increase a person’s cancer risk.

Depression affects about 5% of the world’s adult population. People with depression often have additional mental health issues, most notably anxiety.

Past research shows about 40-50% of people with anxiety will also have depression. And this percentage is similar for people with major depression who also experience anxiety.

Because of the profound impact they can have on the body, depression and anxiety have been linked to an increased risk for certain diseases, including heart diseases like heart attack and stroke, and dementia.

Additionally, previous studies have linked depression and anxiety to a higher risk of developing certain types of cancer.

Now, researchers from the University Medical Center Groningen have discovered evidence to challenge the theory that depression and anxiety increase a person’s cancer risk.

The study was recently published in the journal Cancer, a peer-reviewed journal of the American Cancer Society.

According to the study’s lead author Dr. Lonneke A. van Tuijl, who at the time of the study was a post-doctorate researcher in the Faculty of Medical Sciences at the University Medical Center Groningen and is now an assistant professor in the Department of Clinical Psychology at Utrecht University, it’s a long-held belief that depression and anxiety increase the risk for cancer, but previous studies on the subject are actually quite conflicting.

“Studies also differ in definitions and approaches, making it hard to derive an overall conclusion using more traditional methods,” she told Medical News Today.

“In the PSY-CA consortium, we aimed for more harmony across the included cohorts with how the constructs were defined and the analyses we used. For example, we ensured that we adjusted for smoking behavior and other known risk factors wherever possible,” she said.

For their study, Dr. van Tuijl and her team analyzed data from the International Psychosocial Factors and Cancer Incidence Consortium. This database includes information from 18 prospective study groups with more than 300,000 adults from the Netherlands, the United Kingdom, Norway, and Canada.

The researchers found no associations between depression and anxiety and, overall, breast, prostate, colorectal, and alcohol-related cancers during a follow-up of up to 26 years.

“We hypothesized an association and were a little surprised that this was not the case for overall, breast, prostate, colorectal, and alcohol-related cancers,” Dr. van Tuijl said. “However, the findings were so consistent and clear.”

Depression is a mental health condition where a person experiences a continual feeling of sadness that affects their ability to live their lives.

There are a number of different causes for depression, including:

Like depression, anxiety is also a mood disorder. With anxiety, a person constantly feels worried and nervous.

For some people, anxiety can be a sign of underlying depression. And for others, their anxiety may trigger their depression. It is not uncommon for a person to have both depression and anxiety.

The research team did find depression and anxiety were linked to a 6% higher risk of developing lung cancer and smoking-related cancers, and for anxiety symptoms rising to 24% increased risk for a depression diagnosis.

However, this risk was substantially reduced after adjusting for other cancer-related risk factors, including smoking, alcohol consumption, and body mass index (4% for anxiety symptoms and 8% for a diagnosis of depression).

Scientists believe lung and smoking-related cancer findings support the importance of addressing tobacco use and other unhealthy habits that may develop as a result of depression and/or anxiety.

“I hope that our findings will be used to provide relief to patients with cancer who attribute their diagnosis to previous depression or anxiety,” Dr. van Tuijl said.

“We presented our findings at a scientific conference last year, and an oncologist in the audience was pleased with our findings because it gave her something to provide as evidence to patients who were occupied with thoughts that their diagnoses (were) attributed to a previous depression or anxiety,” she said.

Additionally, Dr. van Tuijl said their next research will be further examining known risk factors and their relationship to depression and anxiety.

“For example, it could be that depression leads to more smoking, which in turn increases the risk for lung cancer,” she continued.

“Or, it could be that the association between anxiety and smoking-related cancers is only evident in people who are overweight. These two possibilities [are] something that we’re researching further in PSY-CA, and the results on this will be published soon,” she added.

After reviewing this study, Dr. Parvin Peddi, a board certified medical oncologist and director of Breast Medical Oncology for the Margie Petersen Breast Center at Providence Saint John’s Health Center and associate professor of medical oncology at Saint John’s Cancer Institute in Santa Monica, California, told Medical News Today these findings are consistent with what she sees in her clinic.

“Although some patients have underlying or previous history of depression/anxiety, many do not,” she explained.

“However, this is very common thinking for patients that they got cancer because of stress, anxiety, or depression, or that if they have ongoing stress, it will make it more likely for cancer to come back. It’s nice to have this study as evidence that this is not true and for patients to, of course, reduce anxiety/stress but not stress about the stress!”
— Dr. Parvin Peddi

Dr. Kristina Espinosa, an accredited clinical psychologist with Miami Cancer Institute, part of Baptist Health South Florida, agreed.

“These findings can offer some relief to our patients who may blame the state of their mental health for the reason they have cancer,” she told MNT. “As a mental health provider, the discussion of how chronic psychological distress can affect one’s outlook and coping ability is ever-evolving.”

“This research offers preliminary alignment with how a variety of factors influence health and illness. Mental health needs to be better understood for interventions to effectively target and reduce risks and increase overall well-being,” Dr. Espinosa added.

For readers looking for ways to lower their overall cancer risk, both Drs. Peddi and Espinosa suggest these tips:

“It is important to note that while these are considerations, other factors, such as genetics and environmental factors that are beyond one’s control, play a role in cancer risk. The key is to maximize prevention by taking the necessary lifestyle changes to reduce risk,” Dr. Espinosa said.