The Mental And Physical Effects Of Depression

Reviewed by Rashonda Douthit, LCSW

Published 06/24/2022

Depression is one of the most prevalent mental ailments. According to the CDC, depression is a mood disorder that affects approximately 26 percent of adults in the United States, with women being diagnosed more than men. Depression can be devastating and result in many severe complications that may affect a person’s mental and physical health. Continue reading to learn more about the mental and physical effects of depression on the body.

An overview of depression

Depression is a complex mental health disorder that involves, feelings of sadness and hopelessness. Symptoms of depression can be brief, sometimes in response to trauma or grief. However, when the symptoms persist beyond two weeks, it could be an indication of a major depressive disorder. The symptoms can also indicate another mental health disorder, such as bipolar disorder or post-traumatic stress disorder (PTSD). The Diagnostic and Statistical Manual of Mental Disorders (DSM-5) highlights the following as signs of depression:

  • Gloomy mood (feelings of emptiness and unhappiness)
  • Lack of interest in previously enjoyable activities
  • Low energy or fatigue
  • Little or excessive sleep
  • Feeling guilty or worthless
  • Indeliberate weight loss or gain
  • Loss of appetite or binge eating
  • Difficulty concentrating

Symptoms depend on the patient and may to change over time. To get a diagnosis of depression, the patient must have experienced five or more symptoms within two weeks. The most common symptoms of depression are emotional, including guilt, sadness, irritability, and feeling hopeless. Other regular symptoms, such as difficulty concentrating on tasks are believed to be associated with the person’s state of mind.

The mental effects of depression

There are a number of theories about the cause of depression. It is thought to sometimes have a biological background and brain chemistry may play a major part. Studies have revealed how changes in the brain’s structure and chemicals can contribute to depression and how a depression diagnosis can alter the brain. These include:

Memory issues

The area of the brain called the hippocampus produces the hormone cortisol during stressful conditions, which includes phases of depression. When the brain gets overwhelmed with cortisol for extended periods, it can compromise or limit the development of new neurons in the hippocampus. This consequently causes a reduction in the size of the hippocampus, which in turn results in memory problems.

Changes to the amygdala

Cortisol flooding in the brain caused by depression can lead to the enlargement of the amygdala. This is the area of the brain responsible for emotional responses. When it enlarges and becomes more active, patients may experience sleep disturbances, hormonal changes, and changes in activity levels.

Inflammation of the brain

It is still unknown if inflammation triggers depression or depression contributes to inflammation. However, studies reveal a connection that people with depression have more inflammation in the brain. One research particularly discovered that people who have dealt with depression for over ten years have 30 percent more inflammation. Brain inflammation can aggravate depression, disrupt the activity of neurotransmitters that control mood, and have adverse effects on learning and memory.


Also known as reduced oxygen, hypoxia has been connected with depressive disorder. When the brain does not get the proper level of oxygen, the person may experience inflammation, damages or the death of brain cells. Consequently, these changes in the brain affect may memory, mood, and learning.

The physical effects of depression

Beyond the mental effects, depression can also have physical symptoms and result in permanent damages to the body due to the direct and indirect implications of dealing with this mental disorder. Some of the physical effects of depression include:


People living with depression may experience unpronounced aches and pains in their limbs, back, or joints. Some people suffer from general body pain, which can be chronic and disturbing. Someone dealing with chronic pain can definitely develop depression, but it is possible that physical and emotional pain can start from the same factor. Scientists are still trying to figure out the connection between depression and physical pain, including the influence they have on one another.

One postulation is that the two can be the result of disruptions of neurotransmitters like serotonin. Some people with pain and depression may notice improvements after taking an antidepressant that affects the reuptake of norepinephrine and serotonin in the brain. Another idea is that people with depression may experience pain in a different way. A study published in 2015 about pain processing discover that people diagnosed with major depressive disorder had a lower threshold and tolerance for pain compared to those without the condition.

Scientists also may have discovered a direct link between depression and lower back pain, a common type of pain in adults. A previous study showed that people with depression are 60 percent more likely to develop back pain than other people. Scientists continue to check the link between pain and depression, including theories concerning chronic inflammation, which may play a role in other physical signs of depression.

Sleeping disorders and depression

When mental health experts and doctors are trying to diagnose depression, sleep disorders are among the major signs they consider. Depressed people usually have a hard time sleeping. The issues may be difficulty sleeping or staying asleep, being unable to sleep restfully, or sleeping excessively. The connection between sleep and depression is a two-way thing because difficulty sleeping due to any cause (like sleep disorder) predisposes a person to develop depression.

Some research has indicated that disruptions to circadian rhythm (which disturbs sleep) can play a part in depression. Knowing how to check the sleep-wake cycle is an option that scientists are considering as they explore new treatment options for depression.

Gastrointestinal disorder

Depressed people may experience recurrent stomach disturbances such as bloating, diarrhea, constipation, or nausea. A viable explanation of these symptoms is related to a neurotransmitter in the brain and gut, known as serotonin. The neurochemical is associated with depression because it is believed to aid mood regulation, but researchers know it also helps to control digestive functions. The production and storage of the body’s serotonin mostly occur in the gut.

Scientists want to learn about the link between the gut and the brain, which could ultimately help them know the effect of mental and digestive health on each other. Aside from serotonin, microbes present in the gut are being evaluated for their possible role in moods and immunity – both of which affect depression.


Stress can weaken a person’s immune system, making them more prone to sickness. When someone with a weak immune system falls sick, recovery takes longer than normal. Certain infections, such as the common cold, are usually not serious. However, a compromised immune system can make the person vulnerable to developing complications due to an infection or getting an infection that fails to respond to treatment.

Researchers are still trying to trace the connection between immunity and depression. Some studies have suggested that chronic stress can trigger an inflammatory response that can alter the functions of the neurochemicals that regulate mood.

Psychomotor symptoms

Psychomotor means symptoms that cause people to feel like they are operating at a different pace than normal. For instance, depression can cause some people to think their thoughts are slower and their movement heavier than normal. Others experience symptoms at the bottom of the scale. They may feel restless, agitated, and unable to sit still. Mentally, they may notice intrusive thoughts and anxiety.

To a level, psychomotor symptoms are often more apparent as people grow older. However, although depression among seniors is also prevalent, it is not usual with aging. Therefore, the mental health professional must also consider the chance that psychomotor changes may be indications of depression and not part of aging.


People with depression usually feel they can never get a restful sleep, regardless of how long they sleep. They may struggle to get out of bed in the morning and find it hard to do daily routines like bathing or house chores. While it is possible that low energy is connected to poor sleep, studies have suggested that the link between fatigue and depression is far more intricate.

Fatigue is not just one of the most prevalent physical effects of depression, but it can be hard to manage as well. In a 2010 study, researchers found that despite taking antidepressants, fatigue persisted in up to 80 percent of people with major depression. Fatigue and depression may become part of a sequence, where persistent low energy and lack of motivation can exacerbate depression. Therefore, managing fatigue is an important aspect of developing an effective treatment plan for a patient diagnosed with depression.

Changes in weight and appetite

 Depression can independently cause people to feel like eating more or less than they usually do. People with depression may notice they have lost or gained weight unintentionally and without any logical explanation.

One factor that may play a part in weight gain is “emotional eating,” which is when people use food to manage the symptoms of depression. These actions can eventually cause weight gain. For people who are overweight or obese, changes in self-image, related health issues, and weight stigma and aggravate depression. The person’s weight or body mass index (BMI)  may explain the connection between weight and depression. For instance, a study in 2019 suggested a particular connection between higher levels of body fat mass and depression since the researchers could not see a link between depression and non-fat body mass.

Depression can also cause weight loss. Low energy, loss of motivation, and lack of appetite can make fixing means harder. Other factors, such as bowel symptoms, can cause weight loss in a depressed person. People with eating disorders such as anorexia nervosa usually develop depression or another mental disorder.

Weight loss caused by eating disorders can be dramatic and may lead to other physical symptoms. Multiple studies have postulated that malnutrition due to poor eating can worsen depression, but more research is required to back this theory. People who are not getting adequate meals for other reasons, like poverty, old age, or health conditions like cancer are also at higher risk of developing depression due to malnutrition. Appetite changes and the resulting weight gain or loss can also occur as a side effect of antidepressants.

High blood pressure

People with depression may experience stress regularly or for extended periods. Although it not the only culprit, chronic stress is known to play a part in high blood pressure or hypertension. Chronic stress, especially, has a connection to raised blood pressure. Consequently, hypertension elevates a person’s predisposition to cardiovascular disease, including strokes and heart attacks. With the increasing amount of evidence to back this, many scientists believe that depression is a contributing factor for cardiovascular disease.

Side effects of medications

Side effects can occur from taking over-the-counter or prescription drugs. Although they are often minor and improve as the body acclimates to the drug, some side effects can be severe and persistent. Medications for treating depression may have side effects, some of which can be physical. Some of the common side effects of antidepressants include blurred vision, dizziness, fatigue, insomnia, nausea, trouble concentrating, sexual dysfunction, and dry mouth.

If it becomes hard to cope with the side effects of medications, the person may eventually stop using them. For those using medications to manage depression, the side effects of antidepressants can inhibit treatment. The mental and emotional side effects of antidepressants can be unpleasant and may suggest that drugs are not the right intervention for you. If, after starting antidepressants, you notice that the symptoms of anxiety and depression worsens, consult your medical professional immediately.

In conclusion

Knowing that depression can have physical and mental effects can encourage people to seek treatment and make adjustments to improve the symptoms. When you visit the doctor to complain about physical symptoms, they may not instantly inquire about emotional signs. However, they will need to consider the emotional, physical and mental effects of the condition to make a correct diagnosis. Be sure to be detailed about how you feel.


Depression can be treated successfully. The mental health professional may recommend a combined treatment approach, including therapy, medications, and lifestyle changes. With the right treatment and support, a person can manage all the effects of depression and lead a normal life. Begin by taking an assessment test for depression.