Causes of Depression

What causes depression?

Depression can be caused by different things in different people. Someone with a family history may develop major depression after a divorce while someone else with a serotonin imbalance may develop the disorder in spite of having no family history or major stressors. Most often, a combination of genetic, environmental, and physiological factors determine whether or not a person develops depression.


Physiological causes

The neurotransmitters serotonin, norepinephrine, and dopamine have been linked to depression1. These important messengers send signals from one part of the brain to another. Serotonin is tied to mood, appetite, sleep, and sexual desire. Dopamine is responsible for reward-seeking and pleasure. And norepinephrine helps regulate the body’s reaction to stress. Some people with depression have imbalanced levels of one or more of these vital neurotransmitters.

Hormones are another physiological factor behind depression. In those with hypothyroidism, depression may develop as the result of decreased thyroid hormone levels in the body. Pregnancy, PMS, and menopause are other conditions that can alter the body’s hormone levels and contribute to depression.

Recent research by One Mind Institute-funded scientists is revealing still more physiological risk factors for depression. Dr. Scott Russo’s research has linked inflammation and a hyperactive immune system as potential depression causes. Dr. Conor Liston’s research has started to distinguish different subtypes of depression based on measured patterns of brain electrical activity, each potentially with a different cause.


Is depression genetic?

Scientists believe that there is a genetic component to depression2. To test this, researchers looked at sets of twins. In identical twins where one twin had depression, the other had a significantly higher chance of developing depression than the general population. This remained true even in situations where identical twins weren’t raised together. In fraternal twins, the probability decreased but still remained higher than in the general population. This suggests that genes do play a role in depression. However, the fact that identical twins-- who share 100% of each other’s DNA-- did not always both develop depression, indicates that genes are only a piece of the puzzle.


Do environmental factors cause depression?

While physiological and genetic components play into depression, a person’s environment is also important3. Major life changes, substance abuse, loss, financial issues, physical abuse, and a host of other environmental stress factors can increase a person’s risk of developing depression.

There are a number of ways to treat depression, including through therapy and medication. However, due to the variety of potential causes, there is no one-size-fits-all treatment plan.

Overcoming depression may mean having patience and working closely with your doctor to determine what forms of treatment are right for you.


Are there any cures for depression? Dr. Scott Russo explains reasons for hope for better treatments and therapies.



  1. Nemade, R., PH. D, Staats Reiss, N., PH. D, & Dombeck, M. (2007, September 19). Biology Of Depression - Neurotransmitters. Retrieved June 8, 2016, from
  2. Levonsin, D. F., M.D., & Nichols, W. E., M.D. (n.d.). Major Depression and Genetics. Retrieved June 9, 2016, from
  3. All About Depression: Causes. (n.d.). Retrieved June 10, 2016, from

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