Depression disorder is a serious sickness. The World Health Organization (WHO) characterizes it as one of the most disabling diseases in the world. Its statistics speak of its widespread existence and how serious this problem has become.

The root cause of depression is not known but inferences are drawn and it appears that more than one factor is involved in causing depression.

You can get depression due to a variety of reasons and they are explained here. Again, you may see depression at any age including in teens (college students), young adults, and the elderly.

Many researchers are of the opinion that depression results from certain chemical changes in the brain.

Research also tells us that many factors contribute to the onset of depression. They can include a genetic vulnerability, hormonal changes in the body, certain chronic medical conditions, anxiety, a chain of stressful events, sorrow, and difficult living conditions.

They can also include your lifestyle habits, stress threshold, and social relationships. Anyone can develop depression including kids.

Any of these factors alone or in combination can precipitate changes in the brain chemicals that can lead to the development of depression symptoms.

And while researchers know a lot more now than ever before about how the brain controls mood, their perception of the biology of depression is yet incomplete.

Facts about depression in men and women

Depression in men and women tells us some interesting facts. According to estimates, 21% of women and 12% of men in the United States will experience depression at some point in their lifetime.

It affects about one in five women and one in ten men at some stage in their lifetime.

Women are twice as likely to develop depression as compared to men. They are more prone to develop this disorder due to stressful life events and seasonal changes.

Certain events during their life make them more prone to getting depressed. It could be during menstruation and after giving birth. Postpartum depression is fairly common.

Women are more likely to experience more intense symptoms such as feelings of guilt and would want to commit suicide. But, statistics for depression in women show that they kill themselves less often than men. And because of biological differences, treatment in women differs.

According to the National Institutes of Mental Health (NIMH), four times more depressed men die from suicide than depressed women.

Depression is of various types and each has its own causes and risk factors.

Causes and risk factors 

Research indicates that there are many different causes of depression and this order can not always be prevented. Causes and factors that can contribute to depression include:

  • Biological changes
  • Brain chemicals
  • Genetics
  • Hormones
  • Stressful events
  • Gender
  • Social factors
  • Certain diseases
  • Certain medicines
  • Lifestyle habits

Biological changes

Certain physical changes do occur in the brain, which leads to depression but what those changes are is still not known. Certain parts of the brain do not function as they should.

Amygdala, the thalamus, and the hippocampus are the areas of the brain that play a significant role in depression. It is their improper functioning that is believed to contribute to the development of depression.

Brain imaging studies such as positron emission tomography (PET), single-photon emission computed tomography (SPECT), and functional magnetic resonance imaging (fMRI) now allows for a closer study of the brain.

fMRI has shown that the appearance of the brain of a person with depression looks different than the normal brain appearance. Research indicates that the hippocampus is 9% to 13% smaller in depressed people compared with those who were not depressed.

But the real reason for depression and these changes still lies undetected.

Brain chemicals – Neurotransmitters

Neurotransmitters are naturally occurring chemicals in the brain, which are responsible for mood sentiment and that relay messages from one neuron to another neuron.

They include

  • Acetylcholine
  • Serotonin
  • Norepinephrine
  • Dopamine
  • Glutamate
  • Gamma-aminobutyric acid (GABA)

These are the chemicals that the brain cells or the nerve cells use to communicate. In depression, changes in the levels of these chemicals are seen and are believed to have a direct bearing on depression.


Research indicates that if you have a family history showing depression in your biological family members, the chances of you developing depression are high. However, the genes responsible for this cause of depression are yet to be identified.

The fact remains that those with depression have a different genetic makeup, but not all people with this genetic makeup develop depression leading to the belief that a combination of factors is responsible for this mood disorder. However, depression is also seen to occur in people without any family history.

Therefore, an important aim of the research is to determine the function of each gene. This will help to know the relationship between biology and environment that leads to the development of depression in some people but not others.


Certain factors cause an imbalance in the body’s hormones, which can trigger depression. Such hormonal imbalances are seen in thyroid diseases.

Women are more susceptible to this cause due to the hormonal changes that occur due to premenstrual syndrome (PMS), menstruation, perimenopause, menopause, and the postpartum period.

Stressful events

Some events can be too great to bear and can cause depression, such as

  • death of a loved one
  • news of a fatal disease such as cancer, heart disease, or AIDS in you or a loved one
  • financial loss or crisis
  • a divorce
  • loss of job
  • social loneliness or lack of social support as seen in the elderly.

Stress triggers a chain of chemical reactions in the body, which can cause undesirable changes. If it is short-lived, the body usually returns to its normal state.

But when stress is chronic and long-lasting, changes in the body and brain can persist for a long time.

Gender: women are more prone

As explained in statistics, women are twice more likely to have depression than men. This could possibly be due to hormonal changes, which are seen in women during different periods of life such as during the onset of puberty, pregnancy, and menopause.

Social factors

People belonging to the minority group are at a greater risk of developing depression due to being discriminated against. Immigrants too feel isolated due to the language barrier.

Certain diseases and disorders

Certain health conditions such as hypogonadism in men can lead to depression. Some chronic diseases too can cause depression.

Such diseases include but are not limited to diabetes, heart disease, kidney disease, arthritis, HIV/AIDS, lupus, multiple sclerosis, and psoriasis.

Several studies suggest that diabetes doubles the risk of depression and the risk increases as diabetes complications develop.

Medical illnesses could be the cause of up to 10% to 15% of all depressions.

Certain medications

Certain drugs prescribed for high blood pressure, sleeping pills, steroids, oral contraceptives, and drugs prescribed for high cholesterol, and acne are some examples of medications that can make you depressed.

Other medications that can trigger depression include barbiturates, vigabatrin, topiramate, flunarizine, corticosteroids, mefloquine, efavirenz, and interferon-α.

Such medications should be used with caution in patients at risk for depression.

Lifestyle habits

There is compelling evidence from research that shows the relationship between depression and various individual lifestyle factors. These include wrong dietary practices, physical inactivity, not getting proper sleep, excessive alcohol intake, chronic tobacco smoking, and illicit drug use.

Causes in children and teens

Certain traumatic events, which have occurred in early childhood, can make you more susceptible to depression.

Such events may be the loss of a parent in early childhood, an experience of physical or sexual abuse, long-term bullying, academic problems, and lack of attention and love.

Causes in the elderly

  • Of the above-explained causes, certain ones are more pertinent to elderly people.
  • Fear of death, anxiety over financial problems or financial instability, and health issues.
  • Loneliness due to staying alone. loss of a spouse, same-age friends, and relatives due to their death.
  • Decreased mobility due to chronic illnesses
  • Chronic pain due to an incurable disease and insufficient funds for treatment
  • Reduced sense of purpose due to retirement