Physiological Effects Of Depression: A Complete Guide

Depression is a serious mental condition that many people suffer from. A lot of people cannot seem to grasp the extent to which depression can control your thought processes, your emotions and feelings and your overall well-being. At the same time, many people put depression into just mental processes, however, any type of diagnosed clinical depression has a huge impact on the physical well-being of that person and the day-to-day functioning. What are the physiological effects of depression? What are the effects on the body such as the nervous system, digestive system, cardiovascular system, and the immune system? What are the effects on the brain and on our sleep? What are the physiological effects of depression in children? What are the differences between the physiological effects of depression and the physiological effects of anxiety? What are tips to help you through the physiological effects of depression?

Physiological Effects Of Depression
Physiological Effects Of Depression

What are the physiological effects of depression?

The physiological effects of depression are a serious issue that causes a person suffering from depression to feel physical effects from it- not just mental effects. Often people who are diagnosed with depression can’t perform as well in their work, social, or educational environments because of the overwhelming feelings of hopelessness, loneliness, and sadness that control them every day. These overwhelming feelings are harmful to someone feeling depressed because they end up missing out on important everyday routines and activities that would have helped them to achieve their goals otherwise if it weren’t for the depression. There are numerous internal body systems, such as the cardiovascular and nervous systems, that are responsible for one’s wellbeing. Depression plays with and alters the state of these systems which is what causes the physiological effects of depression.

What are the physiological effects of depression on the body

According to the American Psychology Foundation (2009), the neuropsychological changes that are seen when someone becomes sad or changes are actually neuro-vegetative signs of depression.

Physiological effects of depression: Nervous system

When we are depressed, our brain is unable to regulate our mood in a way that it should. When regularly regulated, it’s called euthymia; when badly regulated, it’s called dysthymia. Our fight-or-flight mode, from our sympathetic nervous system, is turned on, stays on, and releases cortisol– the stress hormone/neurotransmitter. Our parasympathetic nervous system is also activated sometimes which is what keeps us feeling like we don’t want to move, and why our movements can be slower when depressed- it activates our “rest and digest” mode.

Physiological effects of depression: Digestive system

People with depression experience a lot of problems and changes regarding their eating habits. Some might eat close to nothing or even fast for a bit, while others will go to the opposite end of the continuum and consume amounts of foods they wouldn’t have when they aren’t in the middle of a depressive episode. These sudden appetite changes can cause a lot of problems with the digestive system not only during the depressive episode but also later on in the development of some disorders and diseases. In both directions, there are negative consequences that can lead from this sudden eating change: Type 2 diabetes and obesity from overeating and some form of the eating disorder (anorexia nervosa, bulimia, and others) from restricting or even binging and purging food.

Physiological effects of depression: Cardiovascular system

People who are diagnosed with depression also often worry about many things and experience anxiety. In fact, many times depression and anxiety go hand in hand. High-stress levels contribute to many problems with the cardiovascular system. Your heart rate increases and blood vessels constrict and if you experience that for a prolonged period of time, your body thinks there is a threat present and is always ready. That continuous “fight or flight” state might lead to heart disease in the future. If you are experiencing this, try to think of some relaxation and meditation techniques that could help you slow down your heart rate and calm your breathing.

Many psychologists recommend having a specified “worry time” where instead of worrying all day long about simple and unimportant things, you distract yourself with other things and then worry once a day during a specific time frame. Writing all of your worries down helps as well. That way you can see which worries are less important and which you actually have to focus on. Managing stress is an important coping mechanism and everybody and, especially people diagnosed with depression and anxiety need to deal with adaptively.

Physiological effects of depression: Immune system

When we feel depressed, our immune system weakens- especially in the natural killer T-cells that protect the body from carcinogens (cancer-causing cells). With a weakened immune system, our body’s inflammatory response is also weakened. This along with increased incidences of heart disease, asthma, osteoarthritis, and autoimmune disorders.

What are the physiological effects of depression on the brain

Our brains have neurochemical systems that help us to regulate our moods. When these systems are working normally and as they should, they’re called euthymia. When we feel happy, the neurotransmitters in our brain are released and our brain activates our “feel good” hormones. When we feel sad, our neurotransmitters release hormones that keep us feeling sad.

There are three parts of the brain involved in depression: the hippocampus, the amygdala, and the prefrontal cortex.

The hippocampus is near the center of the brain. Its job is to store memories and regulate the production of cortisol– the stress hormone. During times of mental and physical stress, the body releases cortisol. The problems begin to occur when there are excessive amounts of cortisol released in the brain due to stress or a chemical imbalance in the body. Healthy brains produce neurons (brain cells) throughout life in a part of the hippocampus known as the dentate gyrus. Brains that suffer from depression have long-term exposure to high cortisol levels. These high levels of cortisol slow down the production of new neurons and actually cause the neurons already existing in the hippocampus to shrink. This shrinkage can lead to memory problems.

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Normally, cortisol levels are the highest in the morning and the lowest at night. With depression, cortisol levels are always high- even at night, which is why many people have issues falling asleep when depressed.

The amygdala‘s job is to help facilitate and guide our emotional responses to feelings such as fear and pleasure. When someone suffers from depression, their amygdala becomes enlarged and hyperactive as a response to the high levels of continuous cortisol.

The prefrontal cortex is in the very front part of the brain. Its job is to regulate emotions, from memories, and make decisions. When the body produces too much cortisol, the prefrontal cortex shrinks- just like the neurons in the hippocampus. 

This enlargement and hyperactivity of the amygdala, along with the hyperactive neuron shrinking activity in other parts of the brain, can cause sleeping problems and activity issues. The body releases irregular amounts of hormones and other neurochemicals into the body which can lead to bigger problems later on.

What are the physiological effects of depression on our sleep?

Depression is characterized by changes in your sleep patterns. Many patients vary between having insomnia or sleeping all day. These sleeping changes can cause pains, headaches, migraines and other negative symptoms. It is important to try and get your sleep schedule back on track because sleep is a vital physiological process that is important in people’s well-being and for every-day functioning.

What are the physiological effects of depression in children

With children and teens, it’s important to treat depression as soon as possible to avoid detrimental issues later on in life. Some symptoms children show when depressed are:

Cognitive Symptoms:

  • Impaired thinking
  • Issues completing tasks completely
  • Issues academically (dyslexia and/or dyscalculia)
  • Negative world outlook
  • Attention problems (ADHD)
  • Difficulty organizing thoughts (on paper or speaking)

Physical symptoms:

  • Extreme sleepiness, always tired
  • Changes in weight
  • Appetite change
  • Low energy levels
  • Change in appearance
  • Always fidgeting
  • Acting agitated
  • Stomachaches, headaches, etc. that don’t respond to treatment (such as ibuprofen)
  • Slow and sluggish in responses, movement, and speech

Some long-term effects of childhood and teen depression are:

  • Family problems later on
  • Self-harm, self-mutilation actions
  • Increased risk for physical health problems (such as adult ADHD or anxiety)
  • Panic disorders or social phobias
  • Substance abuse (whether drugs and/or alcohol)
  • Poor emotional health
  • Suicidal thoughts, conduct
  • Interpersonal relationship issues

Physiological effects of depression vs physiological effects of anxiety

The physiological effects of depression can get confused with anxiety symptoms. Depression and anxiety are two birds from the same branch. Often, they go hand-in-hand with each other- they’re rather similar in many aspects. However, there are some differences, too.


  • Both conditions cause a rise in cortisol levels which can affect our cognitive thinking and overall wellbeing in the long run.
  • People are at a greater risk for developing chronic medical conditions if they suffer from either anxiety and/or depression.
  • Both conditions cause a severity in symptoms and greater risk of death when ill compared to someone who doesn’t suffer from either anxiety or depression.
  • Both disorders are related to our emotional functioning within the amygdala.
  • Both anxiety and depression can cause physical addiction or substance abuse to try and quell the dark, strong feelings.
  • Both conditions are known to cause heart disorders and obesity.
  • Both disorders use medical treatment and psychotherapy to be treated. For example, using anti-anxiety medication and/or antidepressants to help aide the conditions’ severity.
  • Appetite changes are normal with both conditions.


  • Anxiety activates the sympathetic nervous system which causes our blood flow to increase, heart rate to rise, and our muscles to tense. Anxiety prepares us to confront danger.
  • Depression tends to have less physical symptoms than anxiety.
  • Depression causes a lack of drive while anxiety causes an increased drive.
  • Anxiety causes a lot of emotions while depression is known for its complete lack of emotion.

Tips to help improve the physiological effects of depression

In addition to therapy and medication, such as antidepressants, there are many ways to help ease the severity of one’s physiological effects of depression.

  • Sleep. A lack of sleep, such as sleep apnea and insomnia, has been shown to reduce brain function which can, in turn, contribute to depression. Luckily, sleeping disorders are quite treatable. Plus, the treatments can actually help reverse the brain damage done from the lack of sleep and improve brain functions.
  • Stay connected with friends, family, and activities to keep from the typically isolated feeling people often get when depressed. Being social and having a support system is mood boosting on many different levels which can lead to a decrease in depression.
  • Get a checkup. While this seems like a given if you’re struggling with depression, long-standing health conditions can contribute not only to your brain fitness but also be a secondary cause for your depression. For example, obesity and being overweight can reduce brain function and subsequently contribute to one’s depression. High cholesterol, hypertension, anemia, concussions, and diabetes can also affect testosterone levels (in men) and lower levels of Vitamin B12.
  • Eat well. Try the Mediterranean diet, which is high in Omega 3s (fish oil is a great source) and low in cholesterol and fat. Plus, the diet includes lots of nuts and fruits. If anything, try taking fish oil supplements to help improve brain function and reduce depression symptoms.
  • Get “up and at ‘em”. Movement and exercise are good for the brain- that’s a no-brainer. Exercise is not only a natural mood booster with the natural release of endorphins, but it’s also a great treatment for depression because of it. Try walking 30 minutes a day. If you want to build up to your 30 minutes, try walking five minutes a day for five days, adding two minutes every other day until you reach 30 minutes a day, five days a week.
  • Try to de-stress. Stress is a major “brain drainer” and can, therefore, be a big contributor to depression and reduction of cognitive function. When feeling stressed, try to meditate, do yoga, or breathing exercises. A good breathing exercise to try is to close your eyes, breath in for seven seconds, hold your breath for seven seconds, and breath out for seven seconds. This exercise induces a response from the parasympathetic nervous system which will calm you down.

Apart from the physiological effects of depression, it has many other negative symptoms and is also highly correlated with substance use disorders. If you suffer from any of these physical symptoms or are feeling down, please seek help whether it be with somebody who you know or a professional. You do not need to suffer alone!

Let us know what you think in the comments below!

This article was written by Anna Bohren in collaboration with  Valerie Sidelkivska.

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