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Does Stress Cause Depression?

Stress gets blamed for a lot of things. Did you gain a few pounds? Blame stress. Say something you regret. Blame stress. But what about something more serious like major depressive disorder? Stress often gets the blame for serious mental illness, but we know that our genetics play a role as well. Depression afflicts an estimated 280 million people worldwide, many of whom would point to stress as a contributing factor to their depression.

Photo by Anna Tarazevich/Pexels

Is it possible to tease apart the complex causes of disorders like major depressive disorder? Researchers have tried to do so, with limited success. Let's highlight some research that has benefited our understanding of this.

Do stressful life events cause major depression? Answering this question comes with several challenges. One of them is the chicken-or-egg question: how do we know that stress causes depression? Or whether someone's depressive mood and behavior caused them stress? One way to address this is through a prospective, longitudinal study in which stress and depression are measured in the same people over the years. This allows us to determine which came first, the stress or the depression.

To address this, researchers asked over 2,000 female twins about their stressful life experiences and symptoms of depression at three different times over about five years. Stressful life events included divorce, the death of a loved one, and job loss, among other events. The researchers took note of the timing of both the stressful event and the onset of the depression symptoms. Their findings should come as no surprise: stressful events often lead to the onset of depressive symptoms. When those who reported depression were asked whether something stressful happened to cause the depression or whether it came out of the blue, 85 percent said that the stressful event came first. None of them reported that depression came before the stressful experience.

Next, the researchers looked at the characteristics of the stressful events. At the risk of blaming the victim, events such as divorce could be partly due to the depressive nature of the individual. By contrast, events such as the death of a loved one should be independent of the depressive nature of the individual. Researchers found that even these independent stressful events, in which the individual had no role, led to the onset of depressive symptoms.

The researchers next took advantage of the fact that their participants were twins. This allows for the assessment of the impact of genetics on the stress-depression relationship. Monozygotic (identical) twins share 100 percent of their genes. Examining the relationship between stress and depression in these twins effectively controlled for the effects of genetics on the development of depression. Within these monozygotic twin pairs, researchers found that stressful life events predicted the onset of depressive symptoms. These findings provide strong support for the idea that stressful life events—even those we have no control over—can lead to the onset of major depression regardless of our genetic makeup.

It's not all doom and gloom, however. The good news is that of the over 2,000 women tested in the study over five years, only about 300 (7 percent) of them developed major depressive disorder. What are the characteristics of these 1,700 women who did not develop depression? The answer to this question may allow us to promote resilience to lessen the negative effects of depression.

A Doctor Writes About Why One Should Not Ignore Signs Of Stress And Burnout

I was dripping with sweat even though I was standing still. I was dizzy. Inside my chest, I felt something new, different, and terrifying. A stampede of wild horses. The air was being knocked out of me. I had a hard time catching my breath. I was in the cardiac intensive care unit in a city called "the most dangerous city in America" in 2007. But I wasn't a patient; I was the doctor. At that moment, I was calmly and methodically making my patient rounds, something I'd done every day for the previous two years.

I was the doctor in charge and fully in control, but in my body, things felt out of control. I was at a standstill in the doorway of a patient's room, trying hard to stop whatever was happening inside me, quite seriously wondering whether I should be the patient in that hospital room instead. The nurse I was working with immediately sensed something wasn't right. She told me to sit down and brought me some orange juice to drink. Seconds later, the feeling passed, and we both laughed it off. "It's probably just low blood sugar from working overnight and not eating enough," she said. I'd been on call the night before, and we'd had many hospital admissions. I'd had no time to eat a full meal, stay hydrated, or even use the bathroom – common occurrences for doctors in training. But still, something else seemed off, and the sensation had me shaking in my scrubs, literally. What had just happened to me?

I'd been working eighty hours a week in my medical training for the previous few years, spending every third night in the hospital on overnight calls. It was a coveted training program for the real-world exposure we received, an ideal learning environment for young doctors like me. But the unpredictable and harsh reality for doctors in training could be intense and sometimes shocking. One night, I saw a pregnant woman being wheeled on a gurney into the trauma ER with bullet wounds in her abdomen. We saw some gruesome stuff, but there wasn't a spare moment to pause, catch our breath, or process what we witnessed. We simply kept going. There was always another seriously ill patient who needed our attention.

If I had a few minutes to spare in the hospital, I'd grab a cold turkey sandwich and a supersized caffeinated drink from the cafeteria and eat on my feet while making notes in patient charts. I rarely saw sunshine, except through the hospital windows. I didn't exercise unless you count running from one patient room to the next. My sleep was erratic, at best. If things were quiet on overnight calls, I would catch a couple of hours of rest in the doctor-on-call room on a worn-out bunk bed. On busy nights, I didn't.

It's how the medical trainee world worked at that time. There was no spare moment to process anything, good or bad. We didn't have the right terminology to describe the emotional aspects of our medical trainee experience. The words "self-care," "stress," and "burnout" didn't exist in my vocabulary or anyone else's two decades ago in the clinical world. I never questioned any of it because I wanted to be counted as someone who could handle it all like I had been taught to do.

Many years before I felt those wild horses in my chest, a teacher at medical school had told me, "Pressure makes diamonds, Aditi. By the end of medical training, you're all going to be gleaming diamonds." I believed him. I became strongly rooted in that belief. I loved the thrilling intensity of my work, so I unknowingly bought into the resilience myth (see below) and persevered through every stage of my trainee experience because, hey . . . Diamond in the making here. But my body told a different story.

That day in the cardiac ICU was the first and last time I ever felt those wild horses during my waking hours. Instead, the palpitations followed me home and visited my body at night just as I was relaxed enough to fall asleep. I'd be jolted awake by the scary, out-of-the-blue sensations. After a half hour or more, I'd drift off to sleep, exhausted and in need of rest. Of course, I was terrified. But I kept it to myself. I thought it was a passing phase. I'd heard about medical student syndrome, a phenomenon where you feel your patients' symptoms. Since I was a doctor in the cardiac ICU taking care of people's hearts, maybe I had just become more aware of my own.

What I didn't know then that I do know now is that my bedtime-only palpitations were a classic manifestation of the delayed stress response.

Excerpted with permission from The 5 Resets: Rewire Your Brain and Body for Less Stress and More Resilience, Aditi Nerurkar, HarperCollins India.

Can Stress Make You Sick? Blood Pressure, Fever And More

When stress continues over a long period of time, the body is impacted in a number of ways, which can have an impact on additional illnesses or health conditions. "These mechanisms lead to burnout and wear-and-tear on the body," says Kelsey M. Latimer, Ph.D., a psychologist based in Palm Beach Gardens, Florida, and the founder of KLM Psychological Services, a concierge therapy provider. "Our mind becomes exhausted and our body starts to attack us."

Conditions impacted by stress include:

Heart Disease

Many studies show the impact stress can have on the heart. Research from 2019 notes that psychosocial stress, which is caused by social threats, such as exclusion or judgments by others, is associated with an increased risk of cardiovascular disease (CVD). It also notes the impact stress has on the cardiovascular system depends on the level and duration of stress, meaning that severe chronic stress may lead to higher risks .

A small 2020 study also suggests that stress isn't always considered when evaluating individuals at risk of cardiovascular disease, but that it should be taken more seriously as a potential inciting factor. The study notes people with stressful work situations, those with a history of abuse and past traumatic events have a higher occurrence of heart disease .

High Blood Pressure

A 2018 review examining the impact of stress on hypertension (high blood pressure) notes that chronic stress can lead to an increase in blood pressure . High blood pressure can put individuals at risk of serious conditions such as stroke and heart disease.

One 2019 study of 1,829 Black adults suggests that high levels of stress experienced over time led to an increased risk of developing high blood pressure. The study also noted that Black individuals may experience higher levels of stress caused by discrimination and socioeconomic factors, placing them at a higher risk of hypertension .

Anxiety and Depression

Anxiety is the body's response to stress. However, when anxiety continues long after the stressful situation has resolved and interferes with daily life, individuals may be diagnosed with an anxiety disorder. "If the stress reactions are not slowed, then the body eventually becomes exhausted," says Dr. Latimer. "This can lead to long-term changes such as anxiety/panic disorder or depression and other conditions that negatively impact our health."

While a number of different factors can cause depression, the Centers for Disease Control and Prevention (CDC) notes that stressful situations—such as unexpected diagnoses, financial difficulties, abuse, grief and major life changes—can all contribute to the development of the condition.

Thirty-three percent of adults who responded to the American Psychological Society's Stress in America survey suggested that they'd experienced sadness or depression as a result of stress, while 34% had felt anxious or nervous because of stress .

Insomnia

In 2022, a survey conducted by The Ohio State University Wexner Medical Center reported that almost one in five Americans had difficulty getting to sleep at night . The American Psychological Society's Stress in America survey also reported that 32% of adults who took part in the survey had experienced a change in their sleeping habits due to stress .

Meanwhile, a 2018 study examining the link between stress-induced worry and insomnia states that stressful and traumatic life events often had a notable impact on how well a person sleeps. The study also points to the dangers of not getting enough sleep, reporting a link between those with insomnia and metabolic disorders and cardiovascular disease .

Fertility Issues

Research suggests a link between stress and fertility issues, although it's not always clear which comes first. One study found a link between higher perceived self-reported stress and a slight reduction in pregnancy. The study also suggests that stress could lead to menstrual cycle changes and a lack of desire for sexual intercourse, both of which may impact a person's chances of getting pregnant .

A 2018 study examining the link between a person's quality of life and their fertility found that women experiencing higher levels of distress also experienced a small reduction in their ability to conceive. However, the study pointed out that more research is needed to establish whether fertility issues causes stress, vice versa or both .

Fever

A 2015 study in Temperature: Medical Physiology and Beyond explores the connection between stress and a rise in body temperature. The study suggests that stress may cause a psychogenic fever, defined as a psychosomatic condition in which a person's body temperature rises in times of chronic stress or when exposed to emotional events .

Still, research on the connection between stress and fever is limited, and much of the research is limited to case studies.

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